CROSS REFERENCE TO RELATED APPLICATION

This application is entitled to the benefit of U.S. Provisional Patent Application Ser. Nos. 61/280,441 filed on Nov. 3, 2009, 61/283,324 filed on Dec. 2, 2009, 61/283,479 filed on Dec. 4, 2009, 61/283,694 filed on Dec. 8, 2009, 61/284,160 filed on Dec. 14, 2009, 61/284,448 filed on Dec. 21, 2009, and 61/399,096 filed on Jul. 6, 2010, which are all incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates generally to semiconductor wafer processing equipments, and more particularly to apparatuses and methods for polishing and cleaning semiconductor wafers.

BACKGROUND OF THE INVENTION

Local and global planarization of semiconductor wafers becomes increasingly important as more metal layers and interlayer dielectric layers are stacked on the wafers. A preferred method to planarize the wafers is a polishing method, where a surface of a semiconductor wafer is polished using a slurry solution supplied between the wafer and a polishing pad. The polished wafer is cleaned using chemicals and deionized (DI) water and then dried before the wafer is further processed in an apparatus for deposition of metallic or dielectric layers or photolithography.

In general, a wafer processing apparatus for polishing semiconductor wafers includes a polishing apparatus and a cleaning apparatus. The polishing apparatus generally comprises multiple polishing tables where polishing pads are placed and multiple polishing heads that support and press the wafers against the polishing pads. The cleaning apparatus generally comprises multiple cleaning chambers for cleaning semiconductor wafers and a dry chamber for drying the cleaned wafers. The wafers polished in the polishing apparatus are cleaned sequentially through the multiple cleaning chambers and then dried in the dry chamber.

One of the most important performance factors of a wafer processing apparatus for polishing and cleaning semiconductor wafers is productivity. For high productivity, a wafer processing apparatus can comprise two cleaning apparatuses because productivity of a wafer processing apparatus can be limited by low productivity of a single cleaning apparatus. When integrating two cleaning apparatuses with a polishing apparatus, the arrangement of the polishing apparatus and the cleaning apparatuses becomes important to efficiently polish and clean multiple semiconductor wafers. In addition, the footprint of a wafer processing apparatus must also be considered since a wafer processing apparatus with a large footprint requires a larger clean room to house the equipment, which translates into greater cost of operation.

Another important performance factor of a wafer processing apparatus for polishing and cleaning semiconductor wafers is ease of maintenance. For easy maintenance, the arrangement of polishing and cleaning apparatuses in a wafer processing apparatus becomes important to provide enough space for engineers to access the polishing and cleaning apparatuses in order to maintain them.

One of the most important performance factors of a cleaning apparatus used in a wafer processing apparatus for polishing and cleaning semiconductor wafers is productivity. For high productivity of a wafer processing apparatus, productivity of a cleaning apparatus needs to be improved because productivity of a wafer processing apparatus can be limited by low productivity of a cleaning apparatus.

One of the most important performance factors of a polishing apparatus used in a wafer processing apparatus for polishing and cleaning semiconductor wafers is productivity. For higher productivity, a polishing apparatus typically requires more polishing tables and more polishing heads. As the numbers of polishing tables and polishing heads included in a polishing apparatus are increased, the efficient arrangement of the polishing tables and the polishing heads becomes important to design a polishing apparatus providing efficient polishing of semiconductor wafers with a small footprint.

Another important performance factor of a polishing apparatus used in a wafer processing apparatus for polishing and cleaning semiconductor wafers is defectivity. Defectivity can be caused by large foreign particles dropping onto polishing pads from moving parts used to transfer polishing heads between the polishing pads. For low defectivity, a polishing apparatus requires an efficient design to protect polishing pads from the foreign particles.

In view of these issues, what is needed is an apparatus and method for polishing and cleaning semiconductor wafers with high productivity, small footprint, sufficient maintenance space and low defectivity.

SUMMARY OF THE INVENTION

An apparatus for polishing an object in accordance with an embodiment of the present invention comprises at least one polishing surface, at least one polishing head assembly comprising at least one polishing head, at least one object transfer station and a transport mechanism configured to transport the at least one polishing head assembly between the at least one polishing surface and the at least one object transfer station. The transport mechanism comprises a support structure comprising an opening disposed over the at least one polishing surface and the at least one object transfer station, at least one inner guide rail supported by the support structure, wherein the at least one inner guide rail is surrounded by the opening, at least one first guide block slidibly coupled to the at least one inner guide rail, at least one outer guide rail supported by the support structure, wherein the at least one outer guide rail surrounds the opening, at least one second guide block slidibly coupled to the outer guide rail, at least one head supporting member mounted to the at least one first guide block and the at least one second guide block, wherein the at least one head supporting member supports the at least one polishing head assembly, and at least one drive mechanism coupled to the at least one head supporting member, wherein the at least one drive mechanism is configured to transport the at least one polishing head assembly coupled to the at least one head supporting member between the at least one polishing surface and the at least one object transfer station.

Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrated by way of example of the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a polishing apparatus in accordance with an embodiment of the present invention.

FIG. 2 is a top view of a polishing module used in the polishing apparatus of FIG. 1.

FIG. 3 is a side view of the polishing module of FIG. 2.

FIGS. 4(a) and 4(b) are tops view of polishing apparatuses in accordance with embodiments of the present invention.

FIG. 5 is a top view of a wafer processing apparatus in accordance with an embodiment of the present invention.

FIG. 6 is a cross-sectional view of a cleaning apparatus used in the wafer processing apparatus of FIG. 5.

FIG. 7 is a top view of a wafer processing apparatus in accordance with an embodiment of the present invention.

FIGS. 8(a) and 8(b) are top views of cleaning apparatuses in accordance with embodiments of the present invention.

FIGS. 9 and 10 are top views of polishing apparatuses in accordance with embodiments of the present invention.

FIGS. 11-13 are top views of wafer processing apparatuses in accordance with embodiments of the present invention.

FIG. 14 is a top view of a polishing apparatus in accordance with an embodiment of the present invention.

FIGS. 15(a) and 15(b) are top views of a pivoting wafer transfer device and washing devices used in the polishing apparatus of FIG. 14.

FIG. 16 is a top view of a wafer processing apparatus in accordance with an embodiment of the present invention.

FIG. 17 is a vertical cross-sectional view of a rotation mechanism in accordance with an embodiment of the present invention.

FIGS. 18 and 19 are plan views of the rotation mechanism of FIG. 17 seen from cross sections 600L1 and 600L2 of the rotation mechanism of FIG. 17, respectively.

FIG. 20 is a vertical cross-sectional view of the rotation mechanism in accordance with an embodiment of the invention.

FIG. 21 is a plan view of the rotation mechanism of FIG. 20 seen from a cross section 600L3 of the rotation mechanism of FIG. 20.

FIG. 22 is a cross-sectional view of a guide rail, a guide block and air nozzles of the rotation mechanism of FIG. 20 in accordance with an embodiment of the present invention.

FIG. 23 is a top view of the rotation mechanism of FIG. 20 seen from a cross section 600L4 of the rotation mechanism of FIG. 20.

FIG. 24 is a perspective sectional side view of the rotation mechanism of FIG. 20.

FIG. 25 is a top view of a polishing apparatus in accordance with an embodiment of the present invention.

FIGS. 26(a)-26(h) are sequential top views of the polishing apparatus of FIG. 25 to show a sequence of polishing wafers in accordance with an embodiment of the present invention.

FIG. 27-29 are top views of wafer processing apparatuses in accordance with embodiments of the present invention.

FIG. 30 is a cross-sectional view of a cleaning apparatus in accordance with an embodiment of the present invention.

FIGS. 31(a)-31(u) are sequential top views of the cleaning apparatus of FIG. 30 to show a method of processing wafers in accordance with an embodiment of the present invention.

FIGS. 32(a) and 32(b) are side views of a wafer output stage in accordance with an embodiment of the present invention.

FIGS. 33-35 are top views of wafer processing apparatuses in accordance with embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, a polishing apparatus 5 in accordance with an embodiment of the present invention is described. FIG. 1 is a top view of the polishing apparatus 5. The polishing apparatus 5 comprises a first polishing module 10, a second polishing module 10â€² and a wafer transfer device 40. The polishing apparatus 5 comprises an enclosure 11 to isolate the polishing modules 10 and 10â€² from the environment. The first polishing module 10 comprises three polishing heads 20a-20c, two polishing surfaces 14a and 14b, and one wafer transfer station 18. The second polishing module 10â€² comprises three polishing heads 20aâ€²-20câ€², two polishing surfaces 14aâ€² and 14bâ€², and one wafer transfer station 18â€². The wafer transfer device 40 is a device to supply wafers to be polished from a wafer source to the wafer transfer stations 18 and 18â€² and to transfer polished wafers from the wafer transfer stations 18 and 18â€² to a wafer storage. The first and second polishing modules 10 and 10â€² are situated in the polishing apparatus 5 such that they are substantially symmetric across an imaginary plane 410.

In the following description of the polishing apparatus 5, only the components of the first polishing module 10 are described. The components of the second polishing module 10â€² are not described separately because the components of the first polishing module are used in the same manner as the components of the second polishing module. The components used in the second polishing module 10â€² are designated with an additional prime symbol (â€²) after the same reference numbers used to designate the components used in the first polishing module 10, similar to the designations of the first and second polishing modules 10 and 10â€². For example, the first polishing heads of the first and second polishing modules 10 and 10â€² are designated as 20a and 20aâ€², respectively.

With reference to FIGS. 2 and 3, the configuration of the polishing module 10 is further described. FIGS. 2 and 3 are top and side views of the polishing module 10, respectively. The polishing surfaces 14a and 14b of the first polishing module 10 are supported on respective polishing tables 13a and 13b and rotated by respective rotation mechanisms about respective rotational axes 15a and 15b. Polyurethane pads can be used as the polishing surfaces 14a and 14b of the polishing module 10. The polishing surfaces 14a and 14b are situated in the polishing module 10 such that an imaginary plane A connecting the rotational axes 15a and 15b is parallel to a depth direction of the polishing module 10, as indicated in FIG. 1.

As shown in FIG. 3, the first polishing head 20a is coupled to an end of a shaft 21a. The other end of the shaft 21a is coupled to a rotational-and-vertical drive mechanism 22a, which controls rotational and vertical motions of the first polishing head 20a. The rotational-and-vertical drive mechanism 22a is coupled to an end of an arm 24a. The other end of the arm 24a is coupled to a rotation mechanism 26. The first polishing head 20a, the shaft 21a, and the rotational-and-vertical drive mechanism 22a form a first polishing head assembly. In the same manner as the first polishing head 20a is coupled to the rotation mechanism 26, the second and third polishing heads 20b and 20c are coupled to the rotation mechanism 26 through respective shafts 21b and 21c, respective rotational-and-vertical drive mechanisms 22b and 22c and respective arms 23b and 23c. The second polishing head 20b, the shaft 21b, and the rotational-and-vertical drive mechanism 22b form a second polishing head assembly. The third polishing head 20c, the shaft 21c, and the rotational-and-vertical drive mechanism 22c form a third polishing head assembly.

The rotation mechanism 26 is overhead mounted above the polishing tables 13a and 13b to a top frame structure (not shown in FIGS. 2 and 3) of the polishing apparatus 5. The rotation mechanism 26 is configured to rotationally transport the polishing heads 20a-20c about a rotation axis 28 between the wafer transfer station 18 and the polishing surfaces 14a and 14b along a circular path 28a. Thus, the rotation mechanism 26 can be considered as a transport mechanism configured to transport polishing head assemblies, which include polishing heads. The circular path 28a is a trajectory of centers 23a-23c of the polishing heads 20a-20c during the rotation about the rotation axis 28 as shown in FIGS. 1 and 2.

The wafer transfer station 18 and the first and second polishing surfaces 14a and 14b are disposed angularly about the rotation axis 28 such that angles from a center 18c of the wafer transfer station 18 to the respective rotation axes 15a and 15b of the first and second polishing surfaces 14a and 14b about the rotation axis 28 may be equal to each other and in the range from 100 to 110 degree. Any device that can transfer wafers with the polishing heads 20a-20c can be used as the wafer transfer station 18.

For polishing wafers, the polishing heads 20a-20c with the wafers are transferred to the polishing surfaces 14a and 14b about the rotation axis 28 by the rotation mechanism 26 and then pressed against the polishing surfaces 14a and 14b. The polishing heads 20a-20c are rotated about the respective rotation axes 23a-23c and the polishing surfaces 14a and 14b are also rotated about the respective rotation axes 15a and 15b. Slurry is supplied onto the polishing surfaces 14a and 14b during this polishing process.

As shown in FIGS. 1 and 2, the polishing surfaces 14a and 14b, the wafer transfer station 18 and the rotation axis 28 are configured and disposed in the polishing module 10 such that the polishing module 10 can have two polishing positions P11 and P12 on the first polishing surface 14a and two polishing positions P21 and P22 on the second polishing surface 14b. In order to polish the wafers held by the polishing heads 20a-20c on the first polishing surface 14a, each of the centers 23a-23c of the polishing heads 20a-20c is positioned on either the position P11 or P12. In order to polish the wafers held by the polishing heads 20a-20c on the second polishing surface 14b, each of the centers 23a-23c of the polishing heads 20a-20c is positioned on either the position P21 or P22.

Still referring to FIG. 2, the positions of P11, P12, P21 and P22 are further described using circumferences of the polishing heads 20a-20c and the polishing surfaces 14a and 14b. As shown in FIG. 2, the polishing heads 20a-20c can be positioned on the first polishing surface 14a such that the circumferences of the polishing heads 20a-20c can have same tangents with the circumference of the first polishing surface 14a at two points 14X and 14X* wherein the point 14X is adjacent to the wafer transfer station 18, and the point 14X* is opposite to the point 14X. The points 14X and 14X* are points on the circumference of the first polishing surface 14a. The polishing heads 20a-20c can be positioned on the second polishing surface 14b such that the circumferences of the polishing heads 20a-20c can have same tangents with the circumference of the second polishing surface 14b at two points 14Y and 14Y* wherein the point 14Y* is adjacent to the wafer transfer station 18, and the point 14Y is opposite to the point 14Y*. The points 14Y and 14Y* are points on the circumference of the second polishing surface 14b. When the circumference of one of the polishing heads 20a-20c has a tangent at either the point 14X or 14X*, the center of that polishing head will be positioned at the polishing position P11 or P12 respectively on the first polishing surface 14a. When the circumference of one of the polishing heads 20a-20c has a tangent at either the point 14Y or 14Y*, the center of that polishing head will be positioned at the polishing position P21 or P22 respectively on the second polishing surface 14b.

In the description of the polishing apparatus 5, positioning the centers 23a-23c of the polishing heads 20a-20c at the polishing position P11 means that the centers 23a-23c can be positioned on the circular path 28a within 1 inch distance range from P11 toward P12; positioning the centers 23a-23c at the polishing position P12 means that the centers 23a-23c can be positioned on the circular path 28a within 1 inch distance range from P12 toward P21; positioning the centers 23a-23c at the polishing position P21 means that the centers 23a-23c can be positioned on the circular path 28a within 1 inch distance range from P21 toward P22; and positioning the centers 23a-23c at the polishing position P22 means that the centers 23a-23c can be positioned on the circular path 28a within 1 inch distance range from P22 toward P21. During the polishing process on the polishing positions P11-P22, the centers 23a-23c of the polishing heads 20a-20c can be oscillated clockwise one inch and counterclockwise one inch to and from P11, P12, P21 and P22 respectively about the rotation axis 28 by the rotation mechanism 26.

Turning back to FIG. 1, the polishing surfaces 14a-14bâ€² of the polishing apparatus 5 are coupled with respective pad conditioning devices 80a-80bâ€² and respective slurry supply arms 90a-90bâ€². Each pad conditioning device 80, i.e., each of the pad conditioning devices 80a-80bâ€², comprises a pivoting mechanism 82, an arm 84 and a conditioning disc 86. The pivoting mechanism 82 is configured to pivot the conditioning disc 86 between the center of the polishing surface 14 and a parking position 87 about an axis 81. Each slurry supply arm 90, i.e., each of the slurry supply arms 90a-90bâ€², comprises a pivoting mechanism 92 and an arm 94. The pivoting mechanism 92 pivots the arm 94 to a central area of the polishing surface 14 about an axis 91.

Depending on the locations of the pad conditioning devices 80a-80bâ€² and the slurry arms 90a-90bâ€² relative to the polishing surfaces 14a-14bâ€², polishing positions on the polishing surfaces 14a-14bâ€² are determined. For example, the polishing apparatus 5 shown in FIG. 1 is configured such that the first polishing module 10 uses P11 and P22 as its polishing positions on the first and second polishing surfaces 14a and 14b respectively; and the second polishing module 10â€² uses P11â€² and P22â€² as its polishing positions on the first and second polishing surfaces 14aâ€² and 14bâ€² respectively.

With different locations of the pad conditioning devices 80a-80bâ€² and the slurry arms 90a-90bâ€² relative to the polishing surfaces 14a and 14bâ€² and different arrangement of the polishing modules 10 and 10â€², different polishing positions can be used as shown in FIGS. 4(a) and 4(c). FIG. 4(a) shows a modified version of the polishing apparatus 5 in accordance with an embodiment of the present invention, which is configured such that the first polishing module 10 uses P12 and P21 as it polishing positions on the first and second polishing surfaces 14a and 14b respectively; and the second polishing module 10â€² uses P12â€² and P21â€² as it polishing positions on the first and second polishing surfaces 14aâ€² and 14bâ€² respectively. FIG. 4(b) shows another modified version of the polishing apparatus 5 in accordance with an embodiment of the present invention, which is configured such that the first polishing module 10 uses P12 and P21 as its polishing positions on the first and second polishing surfaces 14a and 14b respectively; and the second polishing module 10â€² uses P11â€² and P22â€² as its polishing positions on the first and second polishing surfaces 14aâ€² and 14bâ€² respectively.

With reference to FIG. 5, a wafer processing apparatus 100 in accordance with an embodiment of the present invention is described. FIG. 5 is a top view of the wafer processing apparatus 100. The wafer processing apparatus 100 comprises two cleaning apparatuses 120 and 120â€², the polishing apparatus 5, a factory interface 64, a wafer input stage 16a, two cleaner buffers 16b and 16bâ€² (equivalent to â€œcleaner interface stagesâ€ used in U.S. Provisional Patent Applications from which this application claims priority), and two wafer output stages 16c and 16câ€².

The cleaner buffers 16b and 16bâ€² are devices where polished wafers are placed by the wafer transfer device 40. The first cleaner buffer 16b is positioned at a first end 120x of the first cleaning apparatus 120 which is adjacent to the polishing apparatus 5. The second cleaner buffer 16bâ€² is positioned at a first end 120xâ€² of the second cleaning apparatus 120â€² which is adjacent to the polishing apparatus 5. The cleaner buffers 16b and 16bâ€² may be enclosed in the respective cleaning apparatuses 120 and 120â€² as one of the components of the respective cleaning apparatuses 120 and 120â€². Respective second ends 120y and 120yâ€² of the first and second cleaning apparatuses 120 and 120â€² are positioned adjacent to the factory interface 64. The wafer output stages 16c and 16câ€² are positioned at the respective second ends 120y and 120yâ€² of the first and second cleaning apparatuses 120 and 120â€².

The polishing apparatus 5 is disposed in the back side of the wafer processing apparatus 100 such that the respective imaginary planes A and Aâ€² of the polishing modules 10 and 10â€² are parallel to a depth direction of the wafer processing apparatus 100. The cleaning apparatuses 120 and 120â€² are disposed between the factory interface 64 and the polishing apparatus 5 such that longer sides 120a and 120aâ€² of the cleaning apparatuses 120 and 120â€² are parallel to the depth direction of the wafer processing apparatus 100. The cleaning apparatuses 120 and 120â€² are disposed such that there is a space 120S, which is surrounded by the factory interface 64, the cleaning apparatuses 120 and 120â€², and the polishing apparatus 5. The wafer input stage 16a and the wafer transfer device 40 are positioned in the space 120S.

The factory interface 64 includes a cassette 60 and a wafer transfer device 50. The cassette 60 is a device to store wafers to be processed and the wafers that have been processed. The wafer transfer device 50 transfer wafers from the cassette 60 to the wafer input stage 16a and from the wafer output stages 16c and 16câ€² of the cleaning apparatuses 120 and 120â€² to the cassette 60. The factory interface 64 may further comprise a linear track 52. The wafer transfer device 50 is coupled to the linear track 52 such that the wafer transfer device 50 can move linearly along the track 52. The linear track 52 is positioned parallel to a width direction of the wafer processing apparatus 100, as indicated in FIG. 5.

The wafer input stage 16a is a device where wafers that will be transferred by the wafer transfer device 40 are placed by the wafer transfer device 50. The wafer input stage 16a may be coupled to a stage transfer device 77 such that the wafer input stage 16a can move between a wafer receiving position RP1 and a wafer release position RP2 by the stage transfer device 77. The wafer receiving position RP1 is adjacent to the factory interface 64 such that the wafer input stage 16a can receive wafers from the wafer transfer device 50. The wafer release position RP2 is adjacent to the wafer transfer device 40 such that the wafer input stage 16a can release the wafers to the wafer transfer device 40.

The wafer transfer device 40 is positioned in a space surrounded by the wafer transfer stations 18 and 18â€², the cleaner buffers 16b and 16bâ€², and the wafer release position RP2. The wafer transfer device 40 may be mounted to a linear track 42. The linear track 42 is designed and disposed such that the wafer transfer device 40 can move between the wafer release position RP2, the cleaner buffers 16b and 16bâ€², and the wafer transfer stations 18 and 18â€² of the polishing apparatus 5.

With reference to FIG. 6, the cleaning apparatuses 120 and 120â€² are further described. FIG. 6 is a cross sectional view of a cleaning apparatus 120 that can be used as the cleaning apparatuses 120 and 120â€². The cleaning apparatus 120 comprises a cleaning module 124 and a fluid control system 126. The fluid control system 126 controls supply and drain of chemical fluid to and from the cleaning module 124. The cleaning module 124 comprises wafer stages 124a-124d. Wafers are placed on the cleaner buffer 16b by the wafer transfer device 40. An internal wafer transfer device 122 transfers the wafers from the cleaner buffer 16b to the wafer output stage 16c through the wafer stages 124a-124d sequentially. The cleaned and dried wafers are removed from the wafer output stage 16c by the wafer transfer device 50.

The internal wafer transfer device 122 comprises multiple grippers 162a-162e and a vertical-and-lateral transfer mechanism 164. The first gripper 162a transfers a wafer from the cleaner buffer 16b through a first position CP1 and a second position CP2 to the first wafer stage 124a. The second gripper 162b transfers the wafer from the first wafer stage 124a through the second position CP2 and a third position CP3 to the second wafer stage 124b. The third gripper 162c transfers the wafer from the second stage 124b through the third position CP3 and a fourth position CP4 to the third wafer stage 124c. The fourth gripper 162d transfers the wafer from the third stage 124c through the fourth position CP4 and a fifth position CP5 to the fourth wafer stage 124d. The fifth gripper 162e transfers the wafer from the fourth stage 124d through the fifth position CP5 and a sixth position CP6 to the wafer output stage 16c.

Turning back to FIG. 5, a method of processing wafers in the wafer processing apparatus 100 is described. A first wafer W1 is transferred from the cassette 60 to the wafer input stage 16a at the wafer receiving position RP1 by the wafer transfer device 50. The wafer input stage 16a is transferred from the wafer receiving position RP1 to the wafer release position RP2 by the stage transfer device 77. The wafer W1 is transferred from the wafer input stage 16a to the wafer transfer station 18 of the first polishing module 10 by the wafer transfer device 40. The wafer W1 is picked from the wafer transfer station 18 by the first polishing head 20a of the first polishing module 10. The wafer W1 is polished on the first and second polishing surfaces 14a and 14b, and then placed on the wafer transfer station 18 by the first polishing head 20a. The wafer W1 is transferred from the wafer transfer station 18 to the cleaner buffer 16b of the first cleaning apparatus 120 by the wafer transfer device 40, further transferred from there through the cleaning module 124 to the wafer output stage 16c by the internal wafer transfer device 122 and then transferred from the wafer output stage 16c to the cassette 60 by the wafer transfer device 50.

A second wafer W2 is transferred from the cassette 60 to the wafer input stage 16a in the same way as the first wafer W1. The wafer W2 is then transferred from the wafer input stage 16a at the wafer release position RP2 to the wafer transfer station 18â€² of the second polishing module 10â€² by the wafer transfer device 40. The wafer W2 is picked from the wafer transfer station 18â€² by the first polishing head 20aâ€² of the second polishing module 10â€². The wafer W2 is polished on the first and second polishing surfaces 14aâ€² and 14bâ€², and then placed on the wafer transfer station 18â€² by the first polishing head 20aâ€². The wafer W2 is transferred from the wafer transfer station 18â€² to the cleaner buffer 16bâ€² of the second cleaning apparatus 120â€² by the wafer transfer device 40, further transferred from there through the cleaning module 124â€² to the wafer output stage 16câ€² by the internal wafer transfer device 122â€² and then transferred from the wafer output stage 16câ€² to the cassette 60 by the wafer transfer device 50.

In general, a first group of wafers such as the first wafer W1 are processed through one of the polishing modules 10 and 10â€² and one of the cleaning apparatuses 120 and 120â€²; and a second group of wafers such as the second wafer W2 are processed through the other of the polishing modules 10 and 10â€² and the other of the second cleaning apparatuses 120 and 120â€².

With reference to FIG. 7, a modified embodiment 100a of the wafer processing apparatus 100 is described. FIG. 7 is a top view of the modified wafer processing apparatus 100a. The wafer processing apparatus 100a is similar to the wafer processing apparatus 100 shown in FIG. 5. A difference is that the cleaning apparatuses 120 and 120â€² are situated at the same side in the wafer processing apparatus 100a and the wafer input stage 16a and the wafer transfer device 40 are positioned at the opposite side. The cleaning apparatuses 120 and 120â€² are situated such that both of the cleaner buffers 16b and 16bâ€² of the cleaning apparatuses 120 and 120â€² are adjacent to the first polishing surface 14a of the first polishing module 10 of the polishing apparatus 5. The wafer transfer device 40 is configured to transfer wafers from the wafer input stage 16a to the wafer transfer stations 18 and 18â€²; and from the wafer transfer stations 18 and 18â€² to at least one of the first and second cleaner buffers 16b and 16bâ€².

In an embodiment, the cleaning apparatuses 120 and 120â€² used in the wafer processing apparatuses 100a are configured to share the cleaner buffer 16b as described with reference to FIG. 8(a), which is a top view of the cleaning apparatuses 120 and 120â€². In this embodiment, the cleaning apparatuses 120 and 120â€² comprise a stage transfer device 79 to which the shared cleaner buffer 16b is slidibly coupled. The stage transfer device 79 is configured to transfer the cleaner buffer 16b between a first transfer position TP1 and a second transfer position TP1â€². The second transfer position TP1â€² is a position where the cleaner buffer 16b receives wafers from the wafer transfer device 40 and the internal wafer transfer device 122â€² of the second cleaning apparatus 120â€² receives the wafers from the cleaner buffer 16b. The first transfer position TP1 is a position where the internal wafer transfer device 122 of the first cleaning apparatus 120 receives the wafers from the cleaner buffer 16b after the cleaner buffer 16b receives the wafers at the second transfer position TP1â€² from the wafer transfer device 40 and then is transferred to the first transfer position TP1 by the stage transfer device 79.

In an alternative embodiment of the stage transfer device 79, a wafer relay device 172 can be used as shown in FIG. 8(b), which is a top view of the cleaning apparatuses 120 and 120â€². The wafer relay device 172 comprises a linear track 173, a gripping device 174 and a pair of grippers 175a and 175b. The grippers 175a and 175b are coupled to the gripping device 174, which is configured to open and close the grippers 175a and 175b. The gripping device 174 is coupled to the linear track 173 such that the gripping device 174 and therefore the grippers 175a and 175b can move between the cleaner buffers 16b and 16bâ€² on the linear track 173. In an operation, the wafer transfer device 40 transfers a first wafer to the cleaner buffer 16bâ€² of the second cleaning apparatus 120â€² from one of the wafer transfer stations 18 and 18â€². The first wafer is then transferred from the cleaner buffer 16bâ€² by the internal wafer transfer device 122â€² of the second cleaning apparatus 120â€². After the first wafer is transferred from the cleaner buffer 16bâ€² by the internal wafer transfer device 122â€² of the second cleaning apparatus 120â€², the wafer transfer device 40 transfers a second wafer to the cleaner buffer 16bâ€² from the other of the wafer transfer stations 18 and 18â€². The second wafer is then gripped by the grippers 175a and 175b and transferred to the cleaner buffer 16b of the first cleaning apparatus 120 by the wafer relay device 172 such that the internal wafer transfer device 122 of the first cleaning apparatus 120 can take the second wafer from the cleaner buffer 16b.

With reference to FIG. 9, a polishing apparatus 5a in accordance with an embodiment of the present invention is described. FIG. 9 is a top view of the polishing apparatus 5a. The polishing apparatus 5a is similar to the polishing apparatus 5 shown in FIG. 1. A difference is the orientation of the polishing modules 10 and 10â€². In the polishing apparatus 5a, the polishing modules 10 and 10â€² are oriented such that the plane A of the first polishing module 10 is perpendicular to a depth direction of the polishing apparatus 5a and only the plane Aâ€² of the second polishing module 10â€² is parallel to the depth direction of the polishing apparatus 5a, as indicated in FIG. 9. In another embodiment, an angle Q between the plane A and the plane Aâ€² in the polishing apparatus 5a can be any angle in the range of 80 to 95 degree. In another embodiment, the angle Q can have be any angle in the range of 60 to 90 degree. In an embodiment, the first polishing module 10 in the polishing apparatus 5a uses P12 and P22 as its polishing positions on the first and second polishing surfaces 14a and 14b respectively; and the second polishing module 10â€² in the polishing apparatus 5a uses P12â€² and P22â€² as its polishing positions on the first and second polishing surfaces 14a and 14aâ€² respectively.

With reference to FIG. 10, a polishing apparatus 5b in accordance with a modified embodiment of the present invention is described. FIG. 10 is a top view of the polishing apparatus 5b. The polishing apparatus 5b is similar to the polishing apparatus 5a shown in FIG. 9. A difference is that the second polishing module 10â€² may be disposed in the polishing apparatus 5b such that the rotation axis 15bâ€² of the second polishing surface 14bâ€² of the second polishing module 10â€² is disposed further away from the plane A of the first polishing module 10 and closer to the wafer transfer station 18 of the first polishing module 10 than it is disposed in the polishing apparatus 5a in order to make the width of the polishing apparatus 5b smaller. Another difference is that the polishing apparatus 5b may use P21â€² as its polishing position on the second polishing surface 14bâ€² of the second polishing module 10â€² while the polishing apparatus 5a uses P22â€². The polishing apparatuses 5a and 5b can be also configured to use other polishing positions that were used in the polishing apparatus 5 as described with reference to FIGS. 1 and 2. For example, the polishing apparatuses 5a and 5b can be configured to use P11, P22, P11â€² and P22â€²; P12, P21, P12â€² and P21â€²; and P11, P22, P21â€² and P21â€² as their polishing positions.

The polishing apparatus 5a and 5b can be used in the wafer processing apparatus 100 as a replacement of the polishing apparatus 5 shown in FIG. 1. As an example, the wafer processing apparatus 100 comprising the polishing apparatus 5a is described with reference to FIG. 11, which is a top view of the wafer processing apparatus 100 comprising the polishing apparatus 5a. The polishing apparatus 5a is situated in the wafer processing apparatus 100 such that the plane Aâ€² of the second polishing module 10â€² is parallel to the depth direction of the wafer processing apparatus 100. In addition, the second polishing module 10â€² which has the greater depth than the first polishing module 10 is situated adjacent to the first end 120xâ€² of the second cleaning apparatus 120â€²; and the first polishing module 10 which has the smaller depth than the second polishing module 10â€² is situated at the opposite side. The wafer transfer device 40 and the wafer input stage 16a are positioned in the space 120S between the first and second cleaning apparatuses 120 and 120â€². Because the depth of the first polishing module 10 is smaller than the depth of the second polishing module 10â€², there is an empty space 130 between the first polishing module 10 and the first cleaning apparatus 120. Thus, an engineer can access the wafer transfer device 40 and the wafer input stage 16a disposed at the space 120S through this empty space 130 to maintain them.

The polishing apparatuses 5a and 5b can be used in the wafer processing apparatus 100a shown in FIG. 7 as a replacement of the polishing apparatus 5. As an example, the wafer processing apparatus 100a comprising the polishing apparatus 5a is described with reference to FIG. 12, which is a top view of the wafer processing apparatus 100a comprising the polishing apparatus 5a. The second polishing module 10â€² of the polishing apparatus 5a is situated adjacent to the first ends 120x and 120xâ€² of the first and second cleaning apparatuses 120 and 120â€² such that the first and second cleaning apparatuses 120 and 120â€² are situated between the second polishing module 10â€² and the factory interface 64. The wafer transfer device 40 can be mounted on the linear track 42 such that the wafer transfer device 40 can move between about the cleaner buffer 16b of the first cleaning apparatus 120 and about the wafer transfer stations 18 and 18â€² of the polishing modules 10 and 10â€². The wafer transfer device 40 transfers wafers from the wafer input stage 16a to the wafer transfer stations 18 and 18â€²; and from the wafer transfer stations 18 and 18â€² to at least one of the cleaner buffers 16b and 16bâ€². An advantage of the wafer processing apparatus 100a comprising the polishing apparatus 5a is that there is a large space that can be used to maintain the wafer processing apparatus 100a between the first polishing module 10 and the factory interface 64. In an embodiment, the cleaning apparatuses 120 and 120â€² comprises the stage transfer device 79 or the wafer relay device 172, which were described with reference to FIGS. 8(a) and 8(b).

With reference to FIG. 13, a wafer processing apparatus 100b in accordance with an embodiment of the present invention is described. FIG. 13 is a top view of the wafer processing apparatus 100b. The wafer processing apparatus 100b comprises the cleaning apparatuses 120 and 120â€² and a polishing apparatus such as the polishing apparatus 5b shown in FIG. 10. The cleaning apparatuses 120 and 120â€² are disposed adjacent to each other between the first polishing module 10 of the polishing apparatus 5b and the factory interface 64 such that the second ends 120y and 120yâ€² of the cleaning apparatuses 120 and 120â€² are adjacent to the factory interface 64 and the first ends 120x and 120xâ€² of the cleaning apparatuses 120 and 120â€² face the first polishing module 10 of the polishing apparatus 5b across the wafer transfer device 40.

The polishing apparatus 5b is disposed such that there are a space 111a between the first polishing module 10 of the polishing apparatus 5b and the first ends 120x and 120xâ€² of the cleaning apparatuses 120 and 120â€²; a space 111c between the second polishing module 10â€² of the polishing apparatus 5b and the factory interface 64; and a wafer transfer path 111b between the second polishing module 10â€² of the polishing apparatus 5b and the first end 120xâ€² of the second cleaning apparatus 120â€². The wafer transfer path 111b connects the spaces 111a and 111c for wafer transfer between the spaces 111a and 111c. The polishing apparatus 5b may be disposed such that a distance 120D* from the second polishing module 10â€² to the factory interface 64 is shorter than a distance 120D from the first ends 120x and 120xâ€² of the cleaning apparatuses 120 and 120â€² to the factory interface 64.

The wafer transfer device 40 is disposed in the space 111a such that the wafer transfer device 40 can transfer wafers from the wafer transfer stations 18 and 18â€² to at least one of the cleaner buffers 16b and 16bâ€² of the first and second cleaning apparatuses 120 and 120â€². The space 111a also provides a space for an engineer to maintain the cleaning apparatuses 120 and 120â€² and the polishing apparatus 5b.

A buffer 16a* is disposed around the wafer transfer path 111b such that the wafer transfer device 40 can take wafers from the buffer 16a*. The buffer 16a* is a device to keep the wafers transferred by a second wafer transfer device 40*. The buffer 16a* may be configured to accommodate wafers vertically.

The second wafer transfer device 40* is disposed in the space 111c. The second wafer transfer device 40* is configured to transfer wafers to be polished from the wafer input stage 16a disposed adjacent to the factory interface 64 to the buffer 16a*. The second wafer transfer device 40* may be mounted to a linear track 42*.

In an operation of the wafer processing apparatus 100b, wafers to be polished are transferred from the wafer input stage 16a to the buffer 16a* by the second wafer transfer device 40*; transferred from the buffer 16a* to at least one of the wafer transfer stations 18 and 18â€² of the polishing apparatus 5b by the wafer transfer device 40â€²; polished in the polishing apparatus 5b by at least one of the polishing heads 20a-20câ€²; transferred back to at least one of the wafer transfer stations 18 and 18â€² by the at least one of the polishing heads 20a-20câ€²; and transferred from the at least one of the wafer transfer stations 18 and 18â€² to at least one of the cleaner buffers 16b and 16bâ€² of the cleaning apparatuses 120 and 120â€² by the wafer transfer device 40.

Alternatively, the wafer processing apparatus 100b may be configured such that the wafer transfer device 40 transfers the wafers polished in the polishing apparatus 5b back to the buffer 16a* instead of transferring them to the cleaner buffers 16b and 16bâ€². In this embodiment, the wafer transfer device 40* transfers the wafers from the buffer 16a* to at least one of the cleaner buffers 16b and 16bâ€².

With reference to FIG. 14, a polishing apparatus 5c in accordance with an embodiment of the present invention is described. The polishing apparatus 5c is similar to the polishing apparatus 5 shown in FIG. 1. A difference is that the polishing apparatus 5c comprises a pivoting wafer transfer device 180 as a replacement of the wafer transfer stations 18 and 18â€² of the polishing apparatus 5. In addition, the polishing apparatus 5c can further comprise a first washing device 118 and a second washing device 118â€².

The pivoting wafer transfer device 180 is configured to transfer wafers with the polishing heads 20a-20c of the first polishing module 10 at a first transfer position 20P; with the wafer transfer device 40 at a parking position; and with the polishing heads 20aâ€²-20câ€² of the second polishing module 10â€² at a second transfer position 20Pâ€². The first transfer position 20P is a position where the wafer transfer station 18 of the first polishing module 10 was situated in the polishing apparatus 5 shown in FIG. 1; the second transfer position 20Pâ€² is a position where the wafer transfer station 18â€² of the second polishing module 10â€² was situated in the polishing apparatus 5 shown in FIG. 1; and the parking position is a position where a loader 188 of the pivoting wafer transfer device 180 is positioned among the wafer transfer device 40, the first transfer position 20P and the second transfer position 20Pâ€².

The first washing device 118 is disposed about the transfer position 20P and can spray DI water to the polishing heads 20a-20c and the wafers held by the polishing heads 20a-20c when the polishing heads 20a-20c are positioned at the transfer position 20P. The second washing device 118â€² is disposed about the transfer position 20Pâ€² of the second polishing module 10â€² and can spray DI water to the polishing heads 20aâ€²-20câ€² and the wafers held by the polishing heads 20aâ€²-20câ€² when the polishing heads 20aâ€²-20câ€² are positioned at the transfer position 20Pâ€².

With reference to FIGS. 15(a) and 15(b), the pivoting wafer transfer device 180 and the wafer washing devices 118 and 118â€² are further described. FIGS. 15(a) and 15(b) are side views of the pivoting wafer transfer device 180 and the washing devices 118 and 118â€². In FIG. 15(a), the loader 188 is positioned at the parking position and the polishing heads 20a and 20aâ€² are positioned at the first and second transfer positions 20P and 20Pâ€² respectively over the respective washing devices 118 and 118â€². In FIG. 15(b), the loader 188 is positioned at the first transfer position 20P under the first polishing head 20a.

The pivoting wafer transfer device 180 comprises the loader 188, an arm 186, a shaft 184, a pivoting-and-vertical drive mechanism 182 and a pivoting axis 181. The loader 188 is a device to transfer wafers with the polishing heads. The load 188 is coupled to an end of the arm 186. The other end of the arm 186 is coupled to an end of the shaft 184 as shown in FIGS. 15(a) and 15(b). The other end of the shaft 184 is coupled to the pivoting-and-vertical drive mechanism 182. The pivoting-and-vertical drive mechanism 182 is configured to move the loader 188 up and down by moving the shaft 184 up and down; and configured to pivot the loader 188 by pivoting the shaft 184 about the pivoting axis 181.

A procedure of transferring wafers to the polishing heads 20a and 20aâ€² by the loader 188 is described using the polishing head 20a as an example with reference to FIGS. 14, 15(a) and 15(b). The procedure comprises steps of (1) transferring a first wafer from the wafer transfer device 40 to the loader 188 positioned at the parking position; (2) pivoting the loader 188 to the first transfer position 20P; (3) moving the loader 188 upward to the polishing head 20a; (4) transferring the first wafer to the polishing head 20a; (5) moving the loader 188 down from the polishing head 20a; and (6) pivoting the loader 188 back to the parking position. The pivoting wafer transfer device 180 transfers a second wafer to the polishing head 20aâ€² in the same manner as the pivoting wafer transfer device 180 transferred the first wafer to the polishing head 20a.

In an embodiment, as shown in FIG. 14, in order to avoid interference between the loader 188 and the polishing heads 20a-20c and 20aâ€²-20câ€² when the loader 188 is pivoted to the transfer positions 20P and 20Pâ€², the polishing modules 10 and 10â€² in the polishing apparatus 5c preferably uses P12 and P12â€² as its polishing positions to polish the wafers on the first polishing surfaces 14a and 14aâ€² of the polishing modules 10 and 10â€² respectively.

The polishing apparatus 5c shown in FIG. 14 can be used in the wafer processing apparatus 100a shown in FIG. 7 as a replacement of the polishing apparatus 5. FIG. 16 is a top view of the wafer processing apparatus 100a comprising the polishing apparatus 5c. The polishing apparatus 5c and the cleaning apparatuses 120 and 120â€² are disposed in the wafer processing apparatus 100a such that the first polishing surface 14a of the polishing module 10 is adjacent to the first ends 120x and 120xâ€² of the cleaning apparatuses 120 and 120â€². The wafer transfer device 40 is positioned adjacent to the loader 188 of the pivoting wafer transfer device 180 and the first end 120xâ€² of the cleaning apparatus 120â€². The wafer transfer device 40 transfers wafers from the wafer input stage 16a to the loader 188; and from the loader 188 to at least one of the cleaner buffers 16b and 16bâ€².

With reference to FIGS. 17, 18 and 19, a rotation mechanism 600 that can be used as the rotation mechanism 26 of the polishing module 10 shown in FIGS. 2 and 3 is described. FIG. 17 is a vertical cross-sectional view of the rotation mechanism 600 in accordance with an embodiment of the present invention. FIGS. 18 and 19 are plan views of the rotation mechanism 600 seen from cross sections 600L1 and 600L2 shown in FIG. 17 respectively.

Referring to FIGS. 17 and 18, the rotation mechanism 600 comprises a top support 600a, an outer cylindrical support 600b, an inner cylindrical support 600c, and a circular bottom support 600d. The supports 600a, 600b and 600c with or without the support 600d form a support structure of the rotation mechanism 600. The outer and inner cylindrical supports 600b and 600c are mounted to and suspended from the top support 600a such that there is an annular shaped opening 650 between respective lower ends of the outer and inner cylindrical supports 600b and 600c. The outer cylindrical support 600b comprises at least one opening 602, through which the rotation mechanism 600 can be maintained and air can be exhausted from the rotation mechanism 600.

An annular gear 630 is mounted coaxially to the inner cylindrical support 600c about the rotation axis 28. After the gear 630 is mounted, the circular bottom support 600d is mounted to the lower end of the inner cylindrical support 600c such that the bottom support 600d encloses a space 600S surrounded by the inner cylindrical support 600c. The inner space 600S is used for fluid supply channels such as vacuum and pressurized air, electrical power supply cables and data communication cables.

A first annular rim 605 is mounted to the lower end of the outer cylindrical support 600b such that the first annular rim 605 surrounds the annular opening 650. An annular outer guide rail 640a is mounted to the first annular rim 605 and an annular inner guide rail 640b is mounted to the bottom support 600d such that the outer and inner annular guide rails 640a and 640b surround the annular opening 650. Second and third annular rims 608a and 608b are mounted to the outer and inner guide rails 640a and 640b respectively such that they surround the annular opening 650.

A first group of nozzles 610a are mounted to the first annular rim 605 along the first annular rim 605 such that the first group of nozzles 610a can inject pressurized air toward an annular opening 655a (shown in FIG. 17) between the outer cylindrical support 600b and an annular shield 655. A second group of nozzles 610b are mounted to the second annular rim 608a along the second annular rim 608a such that the second group of nozzles 610b can inject pressurized air toward the annular opening 655a (through a space over the outer annular guide rail 640a). A third group of nozzles 610c are mounted to the third annular rim 608b along the third annular rim 608b such that the third group of nozzles 610c can inject pressurized air upwardly toward an annular opening 655b (shown in FIG. 17) between the inner cylindrical support 610c and the annular shield 655 (through a space over the inner annular guide rail 640b). A fourth group of nozzles 610d are mounted to the bottom support 600d along a perimeter of the bottom support 600d such that the fourth group of nozzles 610d can inject pressurized air upwardly toward the annular opening 655b. A fifth group of nozzles 610e may be mounted to the second annular rim 608a along the second annular rim 608a such that the fifth group of nozzles 610e can inject pressurized air toward the annular opening 650. A sixth group of nozzles 610f may be mounted to the third annular rim 608b along the third annular rim 608b such that the sixth group of nozzles 610f can inject pressurized air toward the annular opening 650. Each group of nozzles 610a-610f is connected to a source of the pressurized air (not shown in FIG. 17) through a respective pressure control device such that pressure and flow rate of the pressurized air injected from each group of nozzles can be controlled individually.

Referring to FIG. 17 and FIG. 19, the annular shield 655 is disposed over the opening 650 as shown in FIG. 17 such that it covers the opening 650; an outer radial end of the annular shield 655 is disposed over at least a portion of the outer rail 640a; and an inner radial end of the annular shield 655 is disposed over at least a portion of the inner rail 640b. The annular shield 655 is mounted to the outer cylindrical support 600b through mounting plates 656 as shown in FIG. 19. The annular shield 655 is not connected to the inner cylindrical support 600c. The annular shield 655 may be configured to have the openings 655a between the outer annular support 600b and the annular shield 655. The openings 655a are used to exhaust air from the first and second groups of nozzles 610a and 610b as shown in FIG. 17. The annular shield 655 is also configured such that there is the annular opening 655b between the annular shield 655 and the inner annular support 600c. The opening 655b is used to exhaust air from the third and fourth groups of nozzles 610c and 610d as shown in FIG. 17. The annular shield 655 and the first, second, third and fourth groups of nozzles 610a-610d are used to isolate the annular opening 650 from a space above the annular shield 655. Air injected from the nozzles 610a-610d is used to protect dirty air from flowing into the opening 650 and to blow particles, which may be generated from the guide rails 640a and 640b, to the openings 655a and 655b.

With reference to FIGS. 20 and 21, head supports 615a-615c of the rotation mechanism 600 are described. FIG. 20 is a vertical cross sectional view of the rotation mechanism 600 along a vertical plane Z shown in FIG. 21. FIG. 21 is a plan view of the rotation mechanism 600 seen from a cross section 600L3 shown in FIG. 20. The rotational-and-vertical drive mechanisms 22a-22c of the polishing heads 20a-20c described with reference to FIGS. 2 and 3 are mounted to the head supports 615a-615c respectively. Thus, the head supports 615a-615c are used as head supporting members that support polishing head assemblies, which include polishing heads. As the head supports 615a-615c are similar to each other, details of the head supports 615a-615c are described using the first head support 615a as an example.

The head support 615a is configured such that its outer radial end is positioned over the outer guide rail 640a and movably coupled to the outer guide rail 640a through at least one guide block 645a. The guide block 645a, which is fixedly mounted to the outer radial end of the head support 615a, is movably coupled to the outer guide rail 640a. The head support 615a is also configured such that its inner radial end is positioned over the inner guide rail 640b and movably coupled to the inner guide rail 640b through at least one guide block 647a. The guide blocks 647a, which is fixedly mounted to the inner radial end of the head support 615a, is movably coupled to the inner guide rail 640b. When the head supports 615a-615c are assembled to the rotation mechanism 600, the annular opening 650 is exposed between the head supports 615a-615c as shown in FIG. 21.

With reference to FIG. 22, the head support 615a, the guide rail 640a or 640b, the guide block 645a or 647a and the air nozzles 610a, 610b and 610e or 610c, 610d and 610f of the rotation mechanism 600 of FIG. 20 are further described. FIG. 22 shows a cross-sectional view of the head support 615a, the guide rail 640a or 640b, the guide block 645a or 647a and the air injection nozzles 610a, 610b and 610e or 610c, 610d and 610f of the rotation mechanism 600. The head support 615a may be configured to comprise outer and inner portions 616 and 616* downwardly extended from the outer and inner radial ends of the head support 615a respectively. The portions 616 and 616* are mounted to the respective guide blocks 645a and 647a. The portions 616 and 616* comprise at least one opening 644 through the portions 616 and 616* respectively. The outer portion 616 is positioned between the first and second groups of nozzles 610a and 610b. The second group of nozzles 610b is configured to inject pressurized air through the openings 644. The first group of nozzles 610a is configured to inject pressurized air upwardly. The inner portion 616* is positioned between the third and fourth groups of nozzles 610c and 610d. The third group of nozzles 610c is configured to inject pressurized air through the openings 644. The fourth group of nozzles 610d is configured to inject pressurized air upwardly. The fifth and sixth group of nozzles 610e and 610f are configured to inject pressurized air toward the annular opening 650 in order to supply clean air to wafer processing area under the annular opening 650. In an alternative embodiment, the first and fourth groups of nozzles 610a and 610d may be configured to suction the air injected from the second and third groups of nozzles 610b and 610c respectively.

With reference to FIGS. 20 and 23, the rotation mechanism 600 is further described. FIG. 23 is a plan view of the rotation mechanism 600 seen from a cross section 600L4 shown in FIG. 20. The annular shield 655 is disposed over the head supports 615a-615c. Thus, the annular shield 655 is used as a shield member that shields the opening 650 from the gear 630. A servo motor 642a, which is used to rotate the first head support 615a about the rotation axis 28, is mounted to the first head support 615a as shown in FIG. 20. A gear 643a which is attached to a spinning part of the motor 642a is coupled to the gear 630. When the motor 642a rotates the gear 643a, the gear 643a revolves around the gear 630. A revolution force of the gear 643a is transmitted to the head support 615a such that the head support 615a rotates around the gear 630 on the guide rails 640a and 640b about the rotation axis 28. Respective gears 643b and 643c of servo motors 642b and 642c to drive the head supports 615b and 615c are also coupled with the gear 630 as shown in FIG. 23 such that the head supports 615b and 615c can rotate around the gear 630 on the guide rails 640a and 640b about the rotation axis 28. Thus, the servo motor 642a with the gear 642a and the gear 630 can be considered as one drive mechanism to rotate or transport the connected polishing head assembly. Angular positions of the head supports 615a-615c relative to the rotation axis 28 are controlled individually by a controller 670.

Referring to FIG. 20, the rotation mechanism 600 is further described. The inner cylindrical support 600c comprises outlet port 680a. The outlet port 680a provides an interface with a channel assembly 682a. The channel assembly 682a is connected to fluid sources such as vacuum and pressurized air, electric power source and a controller through the outlet port 680a. The outlet port 680a is connected to an inlet port 680a*, which is mounted to the head support 615a, through the channel assembly 682a. The inlet port 680a* provides an interface with the servo motor 642a and the rotational-and-vertical drive mechanism 22a which will be mounted to the head support 615a.

The channel assembly 682a is suspended from the top support 600a using at least one bendable support 684a. When the head support 615a reciprocates clockwise and counterclockwise about the rotation axis 28 in order to transfer the polishing head 20a coupled to the rotational-and-vertical drive mechanism 22a between the polishing surfaces 14a and 14b and the wafer transfer station 18, the bendable support 684a supports the channel assembly 682a in a bendable manner such that stretching of the channel assembly 682a is not disturbed by the support 684a. The outlet and inlet ports and the channel assemblies of the second and third head supports 615b and 615c have similar configuration with those of the first head support 615a.

With reference to FIG. 24, the rotation mechanism 600 having the polishing heads 20a-20c is described. FIG. 24 is a perspective sectional side view of the rotation mechanism 600. The polishing heads 20a-20c are coupled to the head supports 615a-615c respectively through the respective shafts 21a-21c and the respective rotational-and-vertical drive mechanisms 22a-22c. Therefore the first polishing head assembly comprising the rotational-and-vertical drive mechanism 22a and the first polishing head 20a is coupled to the first head support 615a; the second polishing head assembly comprising the rotational-and-vertical drive mechanism 22b and the second polishing head 20b is coupled to the second head support 615b; and the third polishing head assembly comprising the rotational-and-vertical drive mechanism 22c and the third polishing head 20c is coupled to the third head support 615c.

The polishing heads 20a-20c can be transferred among the first and second polishing surfaces 14a and 14b and the wafer transfer station 18 by rotating the respective gears 643a-643c using the respective motors 642a-642c. The inlet ports 680a*-680c* are coupled to the respective rotational-and-vertical drive mechanisms 22a-22c and the respective polishing heads 20a-20c to supply vacuum, pressurized air and electrical power and to communicate with them.

With reference to FIG. 25, a polishing apparatus 5c* in accordance with an embodiment of the present invention is described. FIG. 25 is a top view of the polishing apparatus 5c*. The polishing apparatus 5c* comprises a single polishing module 110 and the wafer transfer device 40. The polishing module 110 is modified from the polishing module 10 shown in FIGS. 2 and 3 such that the polishing module 110 further comprises a third polishing surface 14c, a fourth polishing head 20d and a second wafer transfer station 18* over the polishing module 10.

The three polishing surfaces 14a-14c and the two wafer transfer stations 18 and 18* of the polishing module 110 are angularly disposed about the rotation axis 28 in a sequence of the first wafer transfer station 18, the first polishing surface 14a, the second polishing surface 14b, the third polishing surface 14c and the second wafer transfer station 18*. The second wafer transfer station 18* is disposed such that the center 18c* of the second wafer transfer station 18* is also positioned on the circular path 28a. The polishing module 110 is configured such that the polishing heads 20a-20d can transfer wafers with any of the wafer transfer stations 18 and 18* and polish wafers on any of the polishing surfaces 14a-14c. The wafer transfer device 40 transfers the wafers with the first and second wafer transfer stations 18 and 18*.

In an operation of the polishing apparatus 5c*, the wafer transfer device 40 sequentially supplies wafers to the first transfer station 18; the polishing heads 20a-20d are sequentially transferred from the second wafer transfer station 18* to the first wafer transfer station 18 in order to sequentially load the wafers from the first transfer station 18; the polishing heads 20a-20d are sequentially transferred from the first wafer transfer station 18 through the polishing surfaces 14a-14c after loading the wafers; the wafers held by the polishing heads 20a-20d are sequentially polished on the polishing surfaces 14a-14c; the polishing heads 20a-20d are sequentially transferred from the third polishing surface 14c to the second wafer transfer station 18*; the wafers are sequentially unloaded from the polishing heads 20a-20d to the second transfer station 18*; and the wafers are sequentially removed from the second transfer station 18* by the wafer transfer device 40.

With reference to FIGS. 26(a)-26(h), another method of processing wafers in the polishing apparatus 5c* is described. FIGS. 26(a)-26(h) are sequential top views of the polishing apparatus 5c* to show a sequence of polishing wafers in accordance with an embodiment of the present invention. The method comprises steps of:

(1) positioning the first, second, third and fourth polishing heads 20a-20d at the first wafer transfer station 18, the second wafer transfer station 18*, the third polishing surface 14c and the second polishing surface 14b respectively; transferring a first wafer W1 to the first wafer transfer station 18 by the wafer transfer device 40; and loading the wafer W1 to the first polishing head 20a from the first wafer transfer station 18 as shown in FIG. 26(a);

(2) transferring the first polishing head 20a from the first wafer transfer station 18 to the first polishing surface 14a; transferring the second polishing head 20b from the second wafer transfer station 18* to the first wafer transfer station 18 such that the second wafer transfer station 18* is cleared to receive the third polishing head 20c; polishing the wafer W1 on the first polishing surface 14a by the first polishing head 20a; and transferring a second wafer W2 to the second wafer transfer station 18* by the wafer transfer device 40 as shown in FIG. 26(b);

(3) transferring the third polishing head 20c to the second wafer transfer station 18*; and loading the wafer W2 to the third polishing head 20c from the second wafer transfer station 18* as shown in FIG. 26(c);

(4) transferring the third polishing head 20c from the second wafer transfer station 18* to the third polishing surface 14c; transferring the second polishing head 20b from the first wafer transfer station 18 to the second wafer transfer station 18* such that the first wafer transfer station 18 is cleared to receive the first polishing head 20a; and polishing the wafer W2 on the third polishing surface 14c by the third polishing head 20c as shown in FIG. 26(d);

(5) transferring the first polishing head 20a from the first polishing surface 14a to the first wafer transfer station 18; and unloading W1 from the first polishing head 20a to the first wafer transfer station 18 as shown in FIG. 26(e);

(6) transferring the wafer W1 from the first wafer transfer station 18 by the wafer transfer device 40; supplying a third wafer W3 to the first wafer transfer station 18 by the wafer transfer device 40; and loading the wafer W3 to the first polishing head 20a as shown in FIG. 26(f);

(7) transferring the first polishing head 20a from the first wafer transfer station 18 to the first polishing surface 14a; transferring the second polishing head 20b from the second wafer transfer station 18* to the first wafer transfer station 18; and polishing W3 on the first polishing surface 14a by the first polishing head 20a as shown in FIGS. 26(g); and

(8) transferring the third polishing head 20c from the third polishing surface 14c to the second wafer transfer station 18*; and unloading the wafer W2 from the third polishing head 20c to the second wafer transfer station 18* as shown in FIG. 26(h).

The wafer W2 is then transferred from the second wafer transfer station 18* by the wafer transfer device 40 and a fourth wafer W4 is supplied to the second wafer transfer station 18* by the wafer transfer device 40. The wafer W4 is processed in the same way as the wafer W2 was processed on the third polishing surface 14c by the third polishing head 20c.

As understandable from the method described with reference to FIGS. 26(a)-26(h), the polishing apparatus 5c* is configured to carry out the above method by positioning the fourth polishing head 20d over the second polishing surface 14b during the entire process; by reciprocating the first polishing head 20a between the first wafer transfer station 18 and the first polishing surface 14a in order to polish a first group of wafers on the first polishing surface 14a by the first polishing head 20a; by reciprocating the third polishing head 20c between the second wafer transfer station 18* and the third polishing surface 14c in order to polish a second group of wafers on the third polishing surface 14c by the third polishing head 20c; and by reciprocating the second polishing head 20b between the first and second wafer transfer stations 18 and 18* such that the second polishing head 20b dose not disturb the reciprocating motions of the first and third polishing heads 20a and 20c.

The polishing apparatus 5c* shown in FIG. 25 can be used in the wafer processing apparatus 100a shown in FIG. 12 as a replacement of the polishing apparatus 5a. FIG. 27 is a top view of the wafer processing apparatus 100a comprising the polishing apparatus 5c*. In the wafer processing apparatus 100a, the polishing apparatus 5c* is disposed such that the third and second polishing surfaces 14c and 14b are aligned to the cleaning apparatuses 120 and 120â€² in the depth direction of the wafer processing apparatus 100a; and the third polishing surface 14c is positioned adjacent to the first ends 120x and 120xâ€² of the cleaning apparatuses 120 and 120â€². The wafer transfer device 40 and the wafer input stage 16a are disposed at the opposite side of the cleaning apparatuses 120 and 120â€². The wafer transfer device 40 may be mounted on the linear track 42 such that the wafer transfer device 40 can be transferred between the wafer input stage 16a and the wafer transfer stations 18 and 18* of the polishing apparatus 5c*. The wafer transfer device 40 transfers wafers from the wafer input stage 16a to the wafer transfer stations 18 and 18* and from the wafer transfer stations 18 and 18* to at least one of the cleaner buffers 16b and 16bâ€².

The polishing apparatus 5c* shown in FIG. 25 can be also used in the wafer processing apparatus 100b shown in FIG. 13 as a replacement of the polishing apparatus 5b. FIG. 28 is a top view of the wafer processing apparatus 100b comprising the polishing apparatus Sc*. The polishing apparatus 5c* is disposed in the wafer processing apparatus 100b such that the wafer transfer device 40 disposed adjacent to the first ends 120x and 120xâ€² of the cleaning apparatuses 120 and 120â€² is surrounded by the first ends 120x and 120xâ€² of the cleaning apparatuses 120 and 120â€², the first and second wafer transfer stations 18 and 18* of the polishing apparatus 5c* and the buffer 16a*. The buffer 16a* is disposed between the first end 120xâ€² of the cleaning apparatus 120â€² and the polishing apparatus Sc*. The polishing apparatus 5c* is also disposed in the wafer processing apparatus 100b such that the third polishing surface 14c faces the factory interface 64 across the second wafer transfer device 40* disposed in the space 111c. In an operation, the second wafer transfer device 40* transfers wafers from the wafer input stage 16a to the buffer 16a*; the wafer transfer device 40 transfers the wafers from the buffer 16a* to the wafer transfer stations 18 and 18* of the polishing apparatus 5c* and from the wafer transfer stations 18 and 18* to at least one of the cleaner buffers 16b and 16bâ€² of the cleaning apparatuses 120 and 120â€².

With reference to FIG. 29, a wafer processing apparatus 200 in accordance with an embodiment of the present invention is described. FIG. 29 is a top view of the wafer processing apparatus 200. The wafer processing apparatus 200 comprises the factory interface 64, two cleaning apparatuses 120V and 120Vâ€², two polishing modules 110a and 110aâ€², the wafer transfer device 40, and the wafer input stage 16a. Each of the two polishing modules 110a and 110aâ€² is modified from the polishing module 110 shown in FIG. 25 by removing the second wafer transfer station 18* from the polishing module 110. Each of the polishing modules 110a and 110aâ€² may comprise one, two or three polishing heads instead of comprising all of the four polishing heads 20a-20d.

The wafer input stage 16a is disposed between a first end 120Vx of the first cleaning apparatus 120V and a second end 120Vyâ€² of the second cleaning apparatus 120Vâ€² such that the wafer transfer device 50 of the factory interface 64 can transfer wafers to the wafer input stage 16a. The wafer input stage 16a may be configured to accommodate the wafers vertically or horizontally.

The wafer transfer device 40 transfers wafers to be polished from the wafer input stage 16a to wafer transfer stations 18 and 18â€² of the polishing modules 110a and 110aâ€² and transfers polished wafers from the wafer transfer stations 18 and 18â€² to respective cleaner buffers 16Vb and 16Vbâ€² of the cleaning apparatuses 120V and 120Vâ€². The wafer transfer device 40 may be mounted on the linear track 42 which extends between the wafer transfer stations 18 and 18â€² and the wafer input stage 16a.

The first cleaning apparatus 120V is disposed adjacent to the factory interface 64 such that (1) its longer side 120Va is parallel to a longer side 64a of the factory interface 64 and therefore parallel to a width direction of the wafer processing apparatus 200; and (2) the first end 120Vx of the first cleaning apparatus 120V is adjacent to the wafer input stage 16a and a second end 120Vy of the first cleaning apparatus 120V which is opposite to the first end 120Vx is disposed adjacent to a second end 64y of the factory interface 64.

The cleaner buffer 16Vb of the first cleaning apparatus 120V is disposed in the first end 120Vx of the first cleaning apparatus 120V such that the wafer transfer device 40 can transfer wafers to the cleaner buffer 16Vb; and a wafer output stage 16Vc is disposed in the second end 120Vy of the first cleaning apparatus 120V such that the wafer transfer device 50 of the factory interface 64 can transfer the wafers from the wafer output stage 16Vc.

The second cleaning apparatus 120Vâ€² is disposed either in the left side or in the right side of the wafer processing apparatus 200 such that (1) its longer side 120Vaâ€² is parallel to a depth direction of the wafer processing apparatus 200; and (2) a second end 120Vyâ€² of the second cleaning apparatus 120Vâ€² is disposed adjacent to a first end 64x of the factory interface 64 such that the wafer transfer device 50 of the factory interface 64 can transfer wafers from a wafer output stage 16Vcâ€² disposed in the second end 120Vyâ€² of the second cleaning apparatus 120Vâ€². A cleaner buffer 16Vbâ€² of the second cleaning apparatus 120Vâ€² is disposed in a first end 120Vxâ€² of the second cleaning apparatus 120Vâ€² which is opposite to the second end 120Vyâ€² of the cleaning apparatus 120Vâ€² such that the wafer transfer device 40 can transfer wafers to the cleaner buffer 16Vbâ€².

With reference to FIG. 30, the cleaning apparatus 120V is further described. The cleaning apparatus 120V can be used as the second cleaning apparatus 120Vâ€². That is, the second cleaning apparatus 120Vâ€² can be identical to the cleaning apparatus 120V. FIG. 30 shows a cross sectional view of the cleaning apparatus 120V in accordance with an embodiment of the present invention. The cleaning apparatus 120V comprises a cleaning module 124V to clean and dry the wafers. The cleaning module 124V comprises cleaning chambers 125Va-125Vd and two dry chambers 125Vx and 125Vy. The cleaning chambers 125Va-125Vd are configured to clean wafers by spraying DI water and chemicals to the wafers placed on respective wafer stages 124Va-124Vd. The dry chambers 125Vx and 125Vy are configured to dry the wafers placed on respective wafer stages 124Vx and 124Vy by spinning the wafers or using isopropyl alcohol (IPA) chemical. The cleaning apparatus 120V further comprises a fluid control system 126V under the cleaning module 124V. The fluid control system 126V controls supply and drain of chemical fluid to and from the cleaning module 124V.

The cleaning apparatus 120V further comprises two internal wafer transfer devices 122a and 122b. The first internal wafer transfer device 122a comprises four gripping devices 70a-70d. Each gripping device comprises a gripper 71 and a vertical-and-gripping drive mechanism 72. The vertical-and-gripping drive mechanism 72 is configured to move the gripper 71 vertically as shown in FIG. 30 by the arrow V and to open and close the gripper 71 to hold a wafer W and release the wafer W. The gripping devices 70a-70d are fixedly mounted to a supporting member 73a, which is coupled to a linear drive mechanism 74a.

The linear drive mechanism 74a is configured to reciprocate the supporting member 73a between a wafer taking position WT1 and a wafer release position WT2 as shown in FIG. 30 by the arrow L1. When the supporting member 73a is positioned at WT1, the gripping devices 70a-70d are positioned at gripper positions C1-C4 respectively. When the supporting member 73a is positioned at WT2, the gripping devices 70a-70d are positioned at gripper positions C2-C5 respectively. The gripper positions C1-C5 are vertically aligned to the cleaner buffer 16Vb and the wafer stages 124Va-124Vd of the cleaning chambers 125Va-125Vd respectively.

The second internal wafer transfer device 122b comprises two gripping devices 70x and 70y. The gripping devices 70x and 70y are fixedly mounted to respective supporting members 73x and 73y, which are slidibly coupled to a liner drive mechanism 74b. The linear drive mechanism 74b is configured to reciprocate the supporting member 73x and therefore the gripping device 70x between fifth, sixth and seventh gripper positions C5-C7 and a parking position 70xp as shown in FIG. 30 with the arrow L2; and to reciprocate the supporting member 73y and therefore the gripping device 70y between the sixth, seventh and eighth gripper positions C6-C8 and a parking position 70yp as shown in FIG. 30 with the arrow L3. The linear drive mechanism 74b is configured to transfer the gripping devices 70x and 70y individually. Alternatively, each of the gripping devices 70x and 70y can be coupled to respective linear drive mechanism instead of being coupled to the same linear drive mechanism 74b such that the gripping devices 70x and 70y can be controlled by the respective linear drive mechanisms. When the gripping devices 70x and 70y are positioned at C5-C8, the gripping devices 70x and 70y are vertically aligned to the wafer stage 124Vd of the fourth cleaning chamber 125Vd, wafer stages 124Vy and 124Vx of the second and first dry chambers 125Vy and 125Vx, and the wafer output stage 16Vc respectively.

With reference to FIGS. 31(a)-31(u), a method of transferring and cleaning wafers in the cleaning apparatus 120V is described. FIGS. 31(a)-31(u) are sequential top views of the cleaning apparatus 120V. The method comprises steps of:

(1) positioning the supporting member 73a of the first internal wafer transfer device 122a at the position WT1; positioning the gripping devices 70x and 70y at the respective parking positions 70xp and 70yp; transferring a first wafer W1 to the cleaner buffer 16Vb by the wafer transfer device 40 (not shown in FIGS. 31(a)-31(u)); lowering the gripping device 70a to the cleaner buffer 16Vb; gripping the wafer W1 from the cleaner buffer 16Vb; and moving the gripping device 70a upward as shown in FIG. 31(a);

(2) transferring the supporting member 73a to the position WT2; transferring a second wafer W2 to the cleaner buffer 16Vb by the wafer transfer device 40; lowering the gripping device 70a to the first cleaning chamber 125Va; placing the wafer W1 to the first cleaning chamber 125Va; moving the gripping device 70a upward; and cleaning the wafer W1 in the first cleaning chamber 125Va as shown in FIG. 31(b);

(3) returning the supporting member 73a to the position WT1; lowering the gripping devices 70b and 70a to the first cleaning chamber 125Va and the cleaner buffer 16Vb respectively; gripping the wafers W1 and W2 from the first cleaning chamber 125Va and the cleaner buffer 16Vb respectively; and moving the gripping devices 70b and 70a upward as shown in FIG. 31(c);

(4) transferring the supporting member 73a to the position WT2; transferring a third wafer W3 to the cleaner buffer 16Vb by the wafer transfer device 40; lowering the gripping devices 70b and 70a to the second and first cleaning chambers 125Vb and 125Va respectively; placing the wafers W1 and W2 to the second and first cleaning chambers 125Vb and 125Va respectively; moving the gripping devices 70b and 70a upward; and cleaning the wafers W1 and W2 in the respective cleaning chambers as shown in FIG. 31(d);

(5) returning the supporting member 73a to the position WT1; lowering the gripping devices 70c-70a to the second and first cleaning chambers 125Vb and 125Va and the cleaner buffer 16Vb respectively; gripping the wafers W1-W3 from the second and first cleaning chambers 125Vb and 125Va and the cleaner buffer 16Vb respectively; and moving the gripping devices 70c-70a upward as shown in FIG. 31(e);

(6) transferring the supporting member 73a to the position WT2; transferring a fourth wafer W4 to the cleaner buffer 16Vb by the wafer transfer device 40; lowering the gripping devices 70c-70a to the third, second and first cleaning chambers 125Vc-125Va respectively; placing the wafers W1-W3 to the third, second and first cleaning chambers 125Vc-125Va respectively; moving the gripping devices 70c-70a upward; and cleaning the wafers W1-W3 in the respective cleaning chambers as shown in FIG. 31(f);

(7) returning the supporting member 73a to the position WT1; lowering the gripping devices 70d-70a to the third, second and first cleaning chambers 125Vc-125Va and the cleaner buffer 16Vb respectively; gripping the wafers W1-W4 from the third, second and first cleaning chambers 125Vc-125Va and the cleaner buffer 16Vb respectively; and moving the gripping devices 70d-70a upward as shown in FIG. 31(g);

(8) transferring the supporting member 73a to the position WT2; lowering the gripping devices 70d-70a to the fourth, third, second and first cleaning chambers 125Vd-125Va respectively; placing the wafers W1-W4 to the fourth, third, second and first cleaning chambers 125Vd-125Va respectively; moving the gripping devices 70d-70a upward; and cleaning the wafers W1-W4 in the respective cleaning chambers as shown in FIG. 31(h);

(9) returning the supporting member 73a to the position WT1; transferring the gripping device 70x of the second internal wafer transfer device 122b to the position C5; lowering the gripping devices 70x and 70d-70b to the fourth, third, second and first cleaning chambers 125Vd-125Va respectively; gripping the wafers W1-W4 from the fourth, third, second and first cleaning chambers 125Vd-125Va respectively; and moving the gripping devices 70x and 70d-70b upward as shown in FIG. 31(i);

(10) transferring the supporting member 73a of the first internal wafer transfer device 122a to the position WT2; transferring the gripping device 70x of the second internal wafer transfer device 122b to the position C7; lowering the gripping devices 70x and 70d-70b to the first dry chamber 125Vx, the fourth, third and second cleaning chambers 125Vd-125Vb respectively; placing the wafers W1-W4 to the respective chambers; moving the gripping devices 70x and 70d-70b upward; and drying the wafer W1 and cleaning the wafers W2-W4 in the respective chambers as shown in FIG. 31(j);

(11) returning the supporting member 73a of the first internal wafer transfer device 122a to the position WT1; transferring the gripping device 70x to the position C5; lowering the gripping devices 70x, 70d and 70c to the fourth, third and second cleaning chambers 125Vd-125Vb respectively; gripping the wafers W2-W4 from the respective chambers; and moving the gripping devices 70x, 70d and 70c upward as shown in FIG. 31(k);

(12) transferring the supporting member 73a to the position WT2; transferring the gripping device 70x to the position C6; lowering the gripping devices 70x, 70d and 70c to the second dry chamber 125Vy, the fourth cleaning chamber 125Vd and the third cleaning chamber 125Vc respectively; placing the wafers W2-W4 to the respective chambers; moving the gripping devices 70x, 70d and 70c upward; and drying the wafer W2 and cleaning the wafers W3 and W4 in the respective chambers as shown in FIG. 31(l);

(13) returning the supporting member 73a to the position WT1; transferring the gripping device 70x to the position C5; transferring the gripping device 70y of the second internal wafer transfer device 122b to the position C7; lowering the gripping devices 70y, 70x and 70d to the first dry chamber 125Vx and the fourth and third cleaning chambers 125Vd and 125Vc respectively; gripping the wafers W1, W3 and W4 from the respective chambers; and moving the gripping devices 70y, 70x and 70d upward as shown in FIG. 31(m);

(14) transferring the supporting member 73a to WT2; transferring the gripping device 70y to C8; transferring the gripping device 70x to C7; lowering the gripping devices 70y, 70x and 70d to the wafer output stage 16Vc, the first dry chamber 125Vx and the fourth cleaning chamber 125Vd respectively; placing W1, W3 and W4 to the wafer output stage 16Vc, the first dry chamber 125Vx and the respective chambers respectively; moving the gripping devices 70y, 70x and 70d upward; and drying W3 in the first dry chamber 125Vx and cleaning W4 in the fourth cleaning chamber 125Vd as shown in FIG. 31(n);

(15) returning the supporting member 73a to the position WT1; transferring the gripping device 70x to C5; transferring the gripping device 70y to the position C6; lowering the gripping devices 70y and 70x to the second dry chamber 125Vy and the fourth cleaning chamber 125Vd respectively; gripping the wafers W2 and W4 from the respective chambers; moving the gripping devices 70y and 70x upward; and transferring the wafer W1 from the wafer output stage 16Vc by the wafer transfer device 50 (not shown in FIGS. 31(a)-31(u)) as shown in FIG. 31(o);

(16) transferring the gripping device 70y to the position C8; transferring the gripping device 70x to the position C6; lowering the gripping devices 70y and 70x to the wafer output stage 16Vc and the second dry chamber 125Vy respectively; placing the wafers W2 and W4 to the wafer output stage 16Vc and the second dry chamber 125Vy respectively; moving the gripping devices 70y and 70x upward; and drying the wafer W4 in the second dry chamber 125Vy as shown in FIG. 31(p);

(17) transferring the gripping device 70x to its parking position 70xp; transferring the gripping device 70y to the position C7; lowering the gripping device 70y to the first dry chamber 125Vx; gripping the wafer W3 from the first dry chamber 125Vx; moving the gripping device 70y upward; and transferring the wafer W2 from the wafer output stage 16Vc by the wafer transfer device 50 as shown in FIG. 31(q);

(18) transferring the gripping device 70y to the position C8; lowering the gripping device 70y to the wafer output stage 16Vc; placing the wafer W3 to the wafer output stage 16Vc; and moving the gripping device 70y upward as shown in FIG. 31(r);

(19) transferring the gripping device 70y to the position C6; lowering the gripping device 70y to the second dry chamber 125Vy; gripping the wafer W4 from the second dry chamber 125Vy; moving the gripping device 70y upward; and transferring the wafer W3 from the wafer output stage 16Vc by the wafer transfer device 50 as shown in FIG. 31(s);

(20) transferring the gripping device 70y to the position C8; lowering the gripping device 70y to the wafer output stage 16Vc; placing the wafer W4 to the wafer output stage 16Vc; and moving the gripping device 70y upward as shown in FIGS. 31(t); and

(21) transferring the gripping device 70y to its parking position 70yp; and transferring the wafer W4 from the wafer output stage 16Vc by the wafer transfer device 50 as shown in FIG. 31(u).

In the method described above, placing the wafers to the dry and cleaning chambers 125Vx, 125Vy and 125Vd-125Va means placing the wafers on the respective wafer stages 124Vx, 124Vy and 124Vd-124Va of the dry and cleaning chambers.

In this sequential manner, a first group of the wafers cleaned in the cleaning chambers 125Va-125Vd are dried in the first dry chamber 125Vx and a second group of the wafers cleaned in the cleaning chambers 125Va-125Vd are dried in the second dry chamber 125Vy.

In an embodiment, the cleaning apparatus 120V may comprise more than two dry chambers between the wafer output stage 16Vc and the last cleaning chamber such as the fourth cleaning chamber 125Vd. In this embodiment, the gripping device 70x of the second internal wafer transfer device 122b transfers wafers from the last cleaning chamber to the plurality of dry chambers, and the gripping device 70y of the second internal wafer transfer device 122b transfers the wafers from the plurality of dry chambers to the wafer output stage 16Vc.

In an embodiment, the second internal wafer transfer device 122b comprises either one of the gripping devices 70x and 70y and is configured such that the one of the gripping devices can transfer wafers from the fourth cleaning chamber 125Vd to the dry chambers 125Vy and 125Vx and from the dry chambers 125Vy and 125Vx to the wafer output stage 16Vc.

In an embodiment, the cleaner buffer 16Vb may be also disposed in a cleaning chamber configured to spray DI water or chemicals to a wafer placed on the cleaner buffer 16Vb.

In an embodiment, the cleaning apparatus 120V may comprise two, three or five cleaning chambers between the dry chamber 125y and the cleaner buffer 16Vb, In this embodiment, the first internal wafer transfer device 122a comprises two, three or five gripping devices 70 respectively.

In the wafer processing apparatuses 100, 100a and 100b described with reference to FIGS. 5, 7, 11-13, 17, 27 and 28, the cleaning apparatuses 120 and 120â€² configured to transfer and process the wafers with the surfaces of the wafers laid horizontal as shown in FIG. 6 were used. However, it is also possible that a cleaning apparatus configured to transfer and process the wafers with the surfaces of the wafers standing vertical such as the cleaning apparatus 120V can be used as replacements of the cleaning apparatuses 120 and 120â€².

Turning back to FIG. 29, the wafer processing apparatus 200 is further described. In an embodiment, the wafer output stage 16Vcâ€² of the second cleaning apparatus 120Vâ€² shown in FIG. 29 may further comprise a pivoting device 16P as shown in FIGS. 32(a) and 32(b), which are side views of the wafer output stage 16Vcâ€² comprising the pivoting device 16P when a wafer is positioned at first and second angles respectively. The pivoting device 16P is configured to pivot the wafer placed on the wafer output stage 16Vcâ€² between the first and second angles about a pivoting axis 16cx which passes vertically through a diameter of the wafer. In an operation, the wafer output stage 16Vcâ€² receives the wafer from the internal wafer transfer device 122Vâ€² of the second cleaning apparatus 120Vâ€² at the first angle as shown in FIG. 32(a) and then the wafer is pivoted to the second angle by the pivoting device 16P about the pivoting axis 16cx as shown in FIG. 32(b). The wafer transfer device 50 transfers the wafer from the wafer output stage 16Vcâ€² after the wafer is positioned at the second angle. A difference between the first and second angles may be 90 degree.

The cleaner buffer 16Vbâ€² of the second cleaning apparatus 120Vâ€² may also comprise the pivoting device 16P. The cleaner buffer 16Vbâ€² receives a wafer from the wafer transfer device 40 at a third angle and then is pivoted to the first angle by the pivoting device 16P. The internal wafer transfer device 122Vâ€² of the second cleaning apparatus 120Vâ€² transfers the wafers from the cleaner buffer 16Vbâ€² after the cleaner buffer 16Vbâ€² changes the orientation to the first angle from the third angle.

Referring to FIG. 29, the layout of the polishing modules 110a and 110aâ€² in the wafer processing apparatus 200 is further described. The second polishing module 110aâ€² is disposed in the back side of the wafer processing apparatus 200 such that (1) the first polishing surface 14aâ€² is adjacent to the first end 120Vxâ€² of the second cleaning apparatus 120Vâ€²; (2) the second polishing surface 14bâ€² is disposed at a corner of the wafer processing apparatus 200 in the back side of the wafer processing apparatus 200; (3) the third polishing surface 14câ€² is disposed in the back side of the wafer processing apparatus 200 such that it faces the first polishing surface 14a of the first polishing module 110a across a line 200L; and (4) the wafer transfer station 18â€² faces the wafer transfer station 18 of the first polishing module 110a across the line 200L.

The first polishing module 110a is disposed in the opposite side of the second polishing module 110aâ€² across the line 200L such that (1) the second and third polishing surfaces 14b and 14c face the first cleaning apparatus 120V across a space SP1; (2) the third polishing surface 14c faces the second cleaning apparatus 120Vâ€² across a space SP2; (3) the first polishing surface 14a faces the third polishing surface 14câ€² of the second polishing module 110aâ€² across the line 200L; and (4) the wafer transfer station 18 is adjacent to the wafer transfer station 18â€² of the second polishing module 110aâ€² and the wafer transfer device 40.

The space SP1 is disposed between the first cleaning apparatus 120V and the first polishing module 110a such that an engineer can access to the first cleaning apparatus 120V through the space SP1 to maintain the first cleaning apparatus 120V. The space SP2 is disposed between the first polishing module 110a and the second cleaning apparatus 120Vâ€². The space SP2 is surrounded by the wafer input stage 16a, the second cleaning apparatus 120Vâ€², the first polishing module 110a, the first cleaning polishing apparatus 120V and the space SP1. The wafer transfer device 40 is disposed in the space SP2.

Still referring to FIG. 29, a method of processing wafers in the wafer processing apparatus 200 is described. The method comprises steps of (1) transferring a first wafer W1 from the cassette 60 to the wafer input stage 16a by the wafer transfer device 50; (2) transferring the wafer W1 from wafer input stage 16a to the wafer transfer station 18 of the first polishing module 110a by the wafer transfer device 40; (3) loading the wafer W1 from the wafer transfer station 18 to the first polishing head 20a of the first polishing module 110a; (4) transferring the first polishing head 20a from the wafer transfer station 18 to the polishing surfaces 14a-14c sequentially about the rotation axis 28 in order to polish the wafer W1 on the polishing surfaces 14a-14c; (5) transferring the first polishing head 20a to the wafer transfer station 18 after polishing the wafer W1; (6) unloading the wafer W1 to the wafer transfer station 18; (7) transferring the wafer W1 from the wafer transfer station 18 to the cleaner buffer 16Vb of the first cleaning apparatus 120V by the wafer transfer device 40; (8) transferring the wafer W1 from the cleaner buffer 16Vb to the wafer output stage 16Vc of the first cleaning apparatus 120V through the cleaning module 124V by the internal wafer transfer device 122V of the first cleaning apparatus 120V in order to clean and dry the wafer W1; and (9) transferring the wafer W1 from the wafer output stage 16Vc to the cassette 60 by the wafer transfer device 50.

The method further comprises steps of (1) transferring a second wafer W2 from the cassette 60 to the wafer input stage 16a by the wafer transfer device 50; (2) transferring the wafer W2 from wafer input stage 16a to the wafer transfer station 18â€² of the second polishing module 110aâ€² by the wafer transfer device 40; (3) loading W2 from the wafer transfer station 18â€² to the first polishing head 20aâ€² of the second polishing module 110aâ€²; (4) transferring the first polishing head 20aâ€² from the wafer transfer station 18â€² to the polishing surfaces 14aâ€²-14câ€² sequentially about the rotation axis 28â€² in order to polish the wafer W2 on the polishing surfaces 14aâ€²-14câ€²; (5) transferring the first polishing head 20aâ€² to the wafer transfer station 18â€² after polishing W2; (6) unloading the wafer W2 to the wafer transfer station 18â€²; (7) transferring the wafer W2 from the wafer transfer station 18â€² to the cleaner buffer 16Vbâ€² of the second cleaning apparatus 120Vâ€² by the wafer transfer device 40; (8) transferring the wafer W2 from the cleaner buffer 16Vbâ€² to the wafer output stage 16Vcâ€² of the second cleaning apparatus 120Vâ€² through the cleaning module 124Vâ€² by the internal wafer transfer device 122Vâ€² of the second cleaning apparatus 120Vâ€² in order to clean and dry the wafer W2; and (9) transferring the wafer W2 from the wafer output stage 16Vcâ€² to the cassette 60 by the wafer transfer device 50.

According to a modified embodiment of the wafer processing apparatus 200, the wafer input stage 16a may be disposed inside the first cleaning apparatus 120V such that the wafer input stage 16a is disposed between the second end 120Vyâ€² of the second cleaning apparatus 120Vâ€² and the cleaner buffer 16Vb of the first cleaning apparatus 120V. In an embodiment the wafer input stage 16a may be positioned over or under the cleaner buffer 16Vb of the first cleaning apparatus 120V.

In another modified embodiment, the wafer processing apparatus 200 may further comprises the second wafer transfer device 40* and the buffer 16a*, which are shown in FIG. 28, in the space SP2 of the polishing apparatus 200 shown in FIG. 29. The second wafer transfer device 40* is disposed between the wafer input stage 16a and the buffer 16a*, and configured to transfer wafers from the wafer input stage 16a to the buffer 16a* and from the buffer 16a* to the cleaner buffer 16Vb of the first cleaning apparatus 120V. The buffer 16a* is disposed between the first and second wafer transfer devices 40 and 40* such that the buffer 16a* can be also reached by the first wafer transfer device 40. The buffer 16a* accommodates wafers transferred by the first and second wafer transfer devices 40 and 40* vertically or horizontally.

In an operation of the wafer processing apparatus 200 further comprising the second wafer transfer device 40* and the buffer 16a*, wafers to be polished are transferred from the wafer input stage 16a to the buffer 16a* by the second wafer transfer device 40* and then transferred from there to the wafer transfer stations 18 and 18â€² of the polishing modules 110a and 110aâ€² by the wafer transfer device 40. After the wafers are polished at one of the polishing modules 110a and 110aâ€², a first group of the polished wafers are transferred from one of the wafer transfer stations 18 and 18â€² to the buffer 16a* by the wafer transfer device 40 and then further transferred from the buffer 16a* to the cleaner buffer 16Vb of the first cleaning apparatus 120V by the second wafer transfer device 40* in order to clean and dry the wafers in the first cleaning apparatus 120V. A second group of the polished wafers are transferred from the other of the wafer transfer stations 18 and 18â€² to the cleaning buffer 16Vbâ€² of the second cleaning apparatus 120Vâ€² by the wafer transfer device 40 in order to clean and dry the wafers in the second cleaning apparatus 120Vâ€².

With reference to FIG. 33, a wafer processing apparatus 300 in accordance with an embodiment of the present invention is described. FIG. 33 is a top view of the wafer processing apparatus 300. The wafer processing apparatus 300 comprises the factory interface 64, the wafer transfer device 40 and a polishing apparatus 305. The polishing apparatus 305 comprises two polishing modules 110a and 110aâ€² used in the wafer processing apparatus 200 shown in FIG. 29. At least one cleaning and dry chambers (not shown in FIG. 33) can be disposed between the factory interface 64 and the polishing apparatus 305 in order to clean and dry wafers polished in the polishing apparatus 305.

The polishing surfaces 14a-14câ€² of the polishing modules 110a and 110aâ€² are disposed such that a line N1 connecting the rotational axes 15a and 15b of the first and second polishing surfaces 14a and 14b of the first polishing module 110a is substantially parallel to a depth direction of the wafer processing apparatus 300; a line N2 connecting the rotational axes 15b and 15c of the second and third polishing surfaces 14b and 14c of the first polishing module 110a is substantially parallel to a width direction of the wafer processing apparatus 300; a line N3 connecting the rotational axes 15aâ€² and 15bâ€² of the first and second polishing surfaces 14aâ€² and 14bâ€² of the second polishing module 110aâ€² is substantially parallel to the width direction; a line N4 connecting the rotational axes 15bâ€² and 15câ€² of the second and third polishing surfaces 14bâ€² and 14câ€² of the second polishing module 110aâ€² is substantially parallel to the depth direction; the polishing surfaces 14aâ€² and 14bâ€² of the second polishing module 110aâ€² are disposed opposite to the factory interface 64 in the back side of the wafer processing apparatus 300; the first polishing surface 14a of the first polishing module 110a, the third polishing surface 14câ€² of the second polishing module 110aâ€² and the wafer transfer stations 18 and 18â€² are disposed between the line N2 and the line N3; and the third polishing surface 14c of the first polishing module 110a, the first polishing surface 14aâ€² of the second polishing module 110aâ€² and the wafer transfer stations 18 and 18â€² are disposed between the line N1 and the line N4.

The wafer transfer device 40 is disposed around the third polishing surfaces 14c and 14câ€² of the first and second polishing modules 110a and 110aâ€² such that the wafer transfer device 40 can transfer wafers to and from the wafer transfer stations 18 and 18â€² of the polishing modules 110a and 110aâ€² through a space G2 between the respective third polishing surfaces 14c and 14câ€² of the first and second polishing modules 110a and 110aâ€².

With reference to FIG. 34, a wafer processing apparatus 500 in accordance with an embodiment of the invention is described. FIG. 34 is a top view of the wafer processing apparatus 500. The wafer processing apparatus 500 comprises a cleaning apparatus 520, two polishing modules 10a and 10aâ€², the factory interface 64, the wafer transfer device 40, a wafer transfer device 40C, the wafer input stage 16a, the buffer 16a*, and the cleaner buffer 16b. The polishing module 10 shown in FIG. 1 can be used as the polishing modules 10a and 10aâ€².

The cleaning apparatus 520 comprises three cleaning chambers 125a-125c and two dry chambers 125x and 125y. However, the cleaning apparatus 520 may comprise six cleaning chambers 125a-125c and 125aâ€²-125câ€² and four dry chambers 125x, 125y, 125xâ€² and 125yâ€² (the cleaning chambers 125aâ€²-125câ€² and the dry chambers 125xâ€² and 125yâ€² are not shown in FIG. 34). The cleaning chambers 125aâ€²-125câ€² may be stacked on the cleaning chambers 125a-125c. The dry chambers 125xâ€² and 125yâ€² may be stacked on the dry chambers 125x and 125y.

The cleaning apparatus 520 is disposed adjacent to the factory interface 64 such that a longer side 520a of the cleaning apparatus 520 is parallel to the longer side 64a of the factory interface 64; and the cleaning apparatus 520 is sandwiched between the factory interface 64 and a linear track 42C which is also disposed parallel to the longer side of the factory interface 64. The wafer transfer device 40C is mounted on the linear track 42C such that the wafer transfer device 40C can transfer wafers from the cleaner buffer 16b to the cleaning chambers 125a-125c and from the cleaning chambers 125a-125c to the dry chambers 125x and 125y. The wafer transfer device 40C is configured to comprise first and second arms 41a and 41b such that the first arm 41a is used to transfer wafers to be cleaned from the cleaner buffer 16b to the cleaning chambers 125a-125c and the second arm 41b is used to transfer wafers cleaned in the cleaning chambers 125a-125c to the dry chambers 125x and 125y. The wafer transfer device 40C is also configured to transfer wafers from the wafer input stage 16a to the buffer 16a*. The wafer input stage 16a is disposed between the cleaning chamber 125a and the dry chamber 125x which are adjacent to each other or disposed over any of the cleaning chambers 125a-125c and the dry chambers 125x and 125y such that the wafer transfer device 50 of the factory interface 64 can transfer wafers to the wafer input stage 16a and the wafer transfer device 40C can transfer wafers from the wafer input stage 16a.

The cleaning chambers 125a-125c and the dry chambers 125x and 125y are configured to have respective first openings toward the wafer transfer device 40C such that the cleaning chambers 125a-125c and the dry chambers 125x and 125y can receive wafers from the wafer transfer device 40C through the respective first openings. The dry chambers 125x and 125y are further configured to have respective second openings toward the wafer transfer device 50 such that the wafer transfer device 50 can take the wafers from the dry chambers 125x and 125y through the respective second openings.

The polishing modules 10a and 10aâ€² and the wafer transfer device 40 are disposed opposite to the factory interface 64 across the wafer transfer device 40C. The buffer 16a* and the cleaner buffer 16b are disposed between the wafer transfer device 40C and the wafer transfer device 40. The wafer transfer device 40 transfers wafers from the buffer 16a* to the wafer transfer stations 18 and 18â€² of the polishing modules 10a and 10aâ€² and from the wafer transfer stations 18 and 18â€² to the cleaner buffer 16b.

The first polishing module 10a is disposed such that a line connecting the rotation axes 15a and 15b of the polishing surfaces 14a and 14b is substantially parallel to a depth direction of the wafer processing apparatus 500, the first polishing surface 14a is adjacent to the linear track 42C, and the wafer transfer station 18 is adjacent to the wafer transfer station 18â€² of the second polishing module 10aâ€² and the wafer transfer device 40.

The second polishing module 10aâ€² is disposed in the back side of the wafer processing apparatus 500 such that a line connecting the rotation axes 15aâ€² and 15bâ€² of the polishing surfaces 14aâ€² and 14bâ€² is substantially parallel to a width direction of the wafer processing apparatus 500; distances from the rotational axes 15aâ€² and 15bâ€² of the polishing surfaces 14aâ€² and 14bâ€² of the second polishing module 10aâ€² to the factory interface 64 is greater than a distance from the rotation axis 15b of the second polishing surface 14b of the first polishing module 10a to the factory interface 64; the wafer transfer station 18â€² faces the wafer transfer device 40; and there is a space SP4 between the second polishing module 10aâ€² and the linear track 42C. The space SP4 provides a space for the wafer transfer device 40, the buffer 16a* and the cleaner buffer 16b. The space SP4 also provides a space through which an engineer can access the polishing modules 10a and 10aâ€² and the cleaning apparatus 520 in order to maintain them.

With reference to FIG. 35, a wafer processing apparatus 600 in accordance with an embodiment of the present invention is described. FIG. 35 is a top view of the wafer processing apparatus 600. The wafer processing apparatus 600 comprises two cleaning apparatuses 620 and 620â€², the factory interface 64 and the wafer transfer device 40C. The wafer transfer device 40C is mounted on the linear track 42C.

Each of the cleaning apparatuses 620 and 620â€² comprises the cleaner buffer 16b, multiple cleaning chambers 125a-125c, the dry chamber 125x and multiple internal wafer transfer devices 127. The cleaning chambers 125a-125c are disposed between the cleaner buffer 16b and the dry chamber 125x. The internal wafer transfer devices 127 are disposed and configured to transfer wafers between the cleaner buffer 16b and the cleaning and dry chambers 125a-125c and 125x.

The first cleaning apparatus 620 is disposed adjacent to the factory interface 64 such that a longer side 620a of the cleaning apparatus 620 is substantially parallel to the longer side 64a of the factory interface 64; and the first cleaning apparatus 620 is sandwiched between the factory interface 64 and the linear track 42C which is also disposed parallel to the longer side of the factory interface 64. The second cleaning apparatus 620â€² is disposed such that the linear track 42C is sandwiched between the first and second cleaning apparatuses 620 and 620â€²; and a longer side 620aâ€² of the second cleaning apparatus 620â€² is substantially parallel to the longer side 620a of the first cleaning apparatus 620.

The wafer processing apparatus 600 further comprises the wafer input stage 16a, the buffer 16a*, the wafer output stage 16c, a second buffer 16b* and the wafer transfer device 40. The wafer input stage 16a and the wafer output stage 16c are disposed about the first cleaning apparatus 620 such that the wafer transfer device 50 of the factory interface 64 can transfer wafers to the wafer input stage 16a and from the wafer output stage 16c; and the wafer transfer device 40C can transfer wafers from the wafer input stage 16a and to the wafer output stage 16c. The wafer input stage 16a and the wafer output stage 16c may be disposed over any of the wafer stages 16b, 124a-124c and 124x of the first cleaning apparatus 620.

The buffer 16a* and the second buffer 16b* are disposed about the second cleaning apparatus 620â€² such that the wafer transfer device 40C can transfer wafers to the buffer 16a* and from the second buffer 16b*; and the wafer transfer device 40 can transfer wafers from the buffer 16a* and to the second buffer 16b*. The buffer 16a* and the second buffer 16b* may be disposed over any of the wafer stages 16bâ€², 124aâ€²-124câ€² and 124xâ€² of the second cleaning apparatus 620â€².

The wafer processing apparatus 600 uses the same polishing modules 10a and 10aâ€² used in the wafer processing apparatus 500 shown in FIG. 34. The wafer transfer device 40 transfers wafers from the buffer 16a* to the wafer transfer stations 18 and 18â€² of the polishing modules 10a and 10aâ€² and from there to the second buffer 16b* and the cleaner buffer 16bâ€² of the second cleaning apparatus 620â€².

A method of processing wafers in the wafer processing apparatus 600 comprises steps of:

(1) transferring a first wafer W1 from the cassette 60 to the wafer input stage 16a by the wafer transfer device 50; transferring the wafer W1 from the wafer input stage 16a to the buffer 16a* by the wafer transfer device 40C; and transferring the wafer W1 from the buffer 16a* to the wafer transfer station 18 of the first polishing module 10a by the wafer transfer device 40;

(2) loading the wafer W1 to the first polishing head 20a of the polishing module 10a from the wafer transfer station 18; transferring the first polishing head 20a to the first and second polishing surfaces 14a and 14b; returning the first polishing head 20a to the wafer transfer station 18; and unloading the wafer W1 from the first polishing head 20a to the wafer transfer station 18;

(3) transferring the wafer W1 from the wafer transfer station 18 to the second buffer 16b* by the wafer transfer device 40; and transferring W1 from the second buffer 16b* to the cleaner buffer 16b of the first cleaning apparatus 620 by the first arm 41a of the wafer transfer device 40C;

(4) transferring the wafer W1 from the cleaner buffer 16b through the cleaning chambers 125a-125c to the dry chamber 125x by the internal wafer transfer devices 127 in order to clean the wafer W1 in the cleaning chambers 125a-125c and dry W1 in the dry chamber 125x; and

(5) transferring the wafer W1 from the dry chamber 125x of the first cleaning apparatus 620 to the cassette 60 by the wafer transfer device 50.

The method of processing wafers in the wafer processing apparatus 600 further comprises steps of: (1) transferring a second wafer W2 from the cassette 60 to the buffer 16a* in the same manner as the first wafer W1 is transferred to the buffer 16a*; and transferring W2 from the buffer 16a* to the wafer transfer station 18â€² of the second polishing module 10aâ€² by the wafer transfer device 40;

(2) loading the wafer W2 to the first polishing head 20aâ€² of the polishing module 10aâ€² from the wafer transfer station 18â€²; transferring the first polishing head 20aâ€² to the first and second polishing surfaces 14aâ€² and 14bâ€²; returning the first polishing head 20aâ€² to the wafer transfer station 18â€²; and unloading the wafer W2 from the first polishing head 20aâ€² to the wafer transfer station 18â€²;

(3) transferring the wafer W2 from the wafer transfer station 18â€² to the cleaner buffer 16bâ€² of the second cleaning apparatus 620â€² by the wafer transfer device 40; and transferring the wafer W2 from the cleaner buffer 16bâ€² through the cleaning chambers 125aâ€²-125câ€² to the dry chamber 125xâ€² by the internal wafer transfer devices 127 in order to clean the wafer W2 in the cleaning chambers 125aâ€²-125câ€² and dry the wafer W2 in the dry chamber 125xâ€²; and

(4) transferring the wafer W2 from the dry chamber 125xâ€² to the wafer output stage 16c by the second arm 41b of the wafer transfer device 40C; and transferring the wafer W2 from the wafer output stage 16c to the cassette 60 by the wafer transfer device 50.

While the present invention has been described with reference to the embodiments thereof, it will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described above, but it is intended to cover modifications within the inventive concept. As an example, although various apparatuses and methods have been described for polishing and cleaning semiconductor wafers, these apparatuses and methods may be used to polish and clean objects other than semiconductor wafers.