FIG. 7 provides an exploded view of a chamber body portion 400. The first item of equipment seen in the view of FIG. 7 is a top cover 470. The top cover 470 is centrally located within the processing area 404, and protrudes through the chamber lid (not seen). The top cover 470 serves as a plate to support certain gas delivery equipment. This equipment includes a gas box 472 which receives gas through a gas supply conduit (not seen). (The conduit is inserted through opening 478 in the bottom 409 of the chamber body 402, as seen in FIG. 5). The gas box 472 feeds gas into a gas input 476. The gas input 476 defines an arm that extends over to the center of the top cover 470. In this way, processing and cleaning gases may be introduced centrally into the processing area 404 above the substrate.

An RF power is supplied to the gas box 472. This serves to generate plasma from the processing gases. A constant voltage gradient 474 is disposed between the gas box 472 and the gas input 476. The constant voltage gradient 474, or “CVG,” controls the power level as the gas moves from the gas box 472 towards the grounded pedestal within the processing area 404.

Immediately below the top cover 470 is a blocker plate 480. The blocker plate 480 defines a plate concentrically placed below the top cover 470. The blocker plate 480 includes a plurality of bolt holes 482. The bolt holes 482 serve as a through-opening through which screws or other connectors may be placed for securing the blocker plate 480 to the top cover 470. A spacing is selected between the blocker plate 480 and the top cover 470. Gas is distributed in this spacing during processing, and then delivered through the blocker plate 480 by means of a plurality of perforations 484. In this way, processing gases may be evenly delivered into the processing area 404 of the chamber 400. The blocker plate 480 also provides a high pressure drop for gases as they are diffused.

Below the blocker plate 480 is a shower head 490. The shower head 490 is concentrically placed below the top cover 470. The shower head 490 includes a plurality of nozzles (not seen) for directing gases downward onto the substrate (not seen). A face plate 496 and isolator ring 498 are secured to the shower head 490. The isolator ring 498 electrically isolates the shower head 490 from the chamber body 402. The isolator ring 498 is preferably fabricated from a smooth and relatively heat resistant material, such as Teflon or ceramic.

Disposed below the shower head 490 is a top liner, or “pumping liner” 410. In the embodiment of FIG. 7, the pumping liner 410 defines a circumferential body having a plurality of pumping holes or apertures 412 disposed there around and through the circumferential body of the pumping liner. During a wafer processing process, a vacuum is pulled from a back side of the top liner 410, drawing gases through the pumping holes 412 and into a channel portion 425 (seen more clearly in FIGS. 6A and 6B). The pumping holes 412 provide the primary flow path for processing gases, as depicted in the schematic view of FIG. 3.

Turning to the enlarged cross sectional views of FIGS. 6A and 6B, features of the top liner 410 can be more readily seen. FIG. 6A provides an enlarged view of cross-sectional area 6A from FIG. 6. Similarly, FIG. 6B provides an enlarged view of area 6B from FIG. 6. The pumping liner 410 is visible in each of these enlarged figures.

The pumping liner 410 defines a circumferential body 410′, and serves to hold a plurality of pumping holes or apertures 412. In the arrangement of FIG. 7, the pumping liner 410 includes an upper lip 414 on an upper surface area (810 in FIG. 8), and a lower shoulder 416 along a lower surface area (812 in FIG. 8). In some embodiments, the upper surface area 810 and the lower surface area 812 are parallel to each other and when implemented in chamber 200 lie in horizontal planes, i.e., the upper surface area 810 and lower surface area 812 of pumping liner 410 lie in planes that are horizontal, i.e., perpendicular to a gravitational vector. In one aspect, the upper lip 414 extends outwardly from the radius of the top liner 410, while the lower shoulder 416 extends radially inward. The upper lip 414 is circumferentially disposed. For this reason, the upper lip 414 is visible in both FIG. 6A and FIG. 6B. However, the lower shoulder 416 does not circumferentially encompass top liner 410, but is left open in the area of upper pumping port liner 442.

Returning to FIG. 4, the chamber 400 next comprises a circumferential liner 420. In the arrangement of FIG. 7, the liner 420 has a profile of an inverted “C”. In addition, the liner 420 includes a channel portion 425. For these reasons, the liner 420 is designated as a “C-channel liner.” The inverted “C” configuration is seen more clearly in the enlarged cross sectional view of FIG. 6B. With continuing reference to FIG. 6B, the C-channel liner 420 has an upper arm 421, a lower arm 423, and an intermediate inner body 422. The upper arm 421 has an upper shoulder 424 formed therein. The upper shoulder 424 is configured to receive the upper lip 414 of the pumping liner 410. At the same time, the lower arm 423 is configured to receive the lower shoulder 416 of the top liner 410. This interlocking arrangement between the top liner 410 and the C-channel liner 420 provides a circuitous interface that substantially reduces unwanted parasitic pumping. In this way, as gases are exhausted from the processing area 404 of the chamber 400 and through the pumping holes 412 of the pumping liner 410, gas is preferentially evacuated through the channel portion 425 of the C-channel liner 420.

In the process kit 40 arrangement of FIGS. 6A, 6B and 7, the upper shoulder 424 is circumferentially disposed along the upper arm 421. For this reason, the upper shoulder 424 is visible in both FIG. 6A and FIG. 6B. However, the lower lip 426 does not circumferentially encompass the C-channel liner 420, but is also left open in the area of the upper pumping port liner 442. Thus, a radial portion is left open to form a pumping port liner opening 429.

As indicated from the cutaway perspective view provided in FIG. 6, areas 6A and 6B show opposite ends of the chamber 400. The cutaway end from area 6A includes gas exhaust ports, referred to as “pumping port liners” 442, 444. An upper pumping port liner 442 is provided below the channel portion 425 of the C-channel liner 420. A lower pumping port liner 444 is then provided in fluid communication with the upper pumping port liner 442. Gas may then be exhausted out of the lower pumping port liner 444 and away from the processing chamber 400 by means of an exhaust system.

To further limit parasitic pumping at the area of the pumping port liners 442, 444, a seal member 427 is provided at the interface between the C-channel liner 420 and the upper pumping port liner 442, and at the interface between the top liner 410 and the upper pumping port liner 442. The seal member is visible at 427 in both FIG. 7 and FIG. 6B. Preferably, the seal member 427 defines a circular ring that encompasses the upper pumping port liner 442. The seal member 427 is preferably fabricated from a Teflon material or otherwise includes a highly polished surface. The seal 427 further enables the C-channel liner 420 to interlock with the pumping ports 442, 444 and to limit gas leakage.

Referring back to FIG. 7, a middle liner 440 is next disposed below the C-channel liner 420. The middle liner 440 resides in the process area 404 at the level of the slit 432. It can be seen from FIG. 7 that the middle liner 440 is a C-shaped liner, and is not circular. The open area in the middle liner 440 is configured to receive wafers as they are imported into the process chamber 400. The middle liner 440 can be partially seen in both FIG. 6A and FIG. 6B, residing below C-channel liner 420 and top liner 410.

Also visible in FIG. 7 is a bottom liner 450. In the arrangement of FIG. 7, the bottom liner 450 is disposed in the chamber 400 below the middle liner 440. The bottom liner 450 resides between middle liner 440 and bottom surface 409 of chamber 400.

Additional process kit items seen in FIG. 7 include a filler member 430 and a pressure equalization port liner 436. The filler member 430 is placed around the middle 440 and bottom 450 liners in order to fill space between the outer diameters of these liners 440, 450 and the surrounding chamber body 402. The presence of the filler member 430 aides in channeling the collection of carbon residues behind the liners 440, 450 by keeping residues from forming behind the liners 440, 450.

It is noted that the filler member 430, like the middle liner 440, is not completely circumferential. In this respect, an open portion is retained in the filler member 430 to provide fluid communication between the two process areas 404. The pressure equalization port liner 436 controls the fluid communication between the two process areas 404 by defining a sized orifice. The presence of the pressure equalization port liner 436 insures that pressures between the two process areas 404 remain the same.

It is also noted at this point that the filler member 430, the pressure equalization port liner 436, and the upper 442 and lower 444 pumping port liners are preferably coated with a highly smoothed material. An example is a polished aluminum coating. Other examples of materials provided with a very smooth surface include polymer coatings, Teflon, ceramics and quartz.

To further aide in the reduction of deposition on chamber parts, a slit valve liner 434 is provided along the slit 432. The slit valve liner 434 is likewise fabricated from a highly smoothed material such as those mentioned above.

During a deposition or etching process, the processing areas 404 is typically heated. To this end, a heater is provided with the pedestal for supporting wafers. A heater pedestal is seen at 462 in the chamber arrangement 400 of FIG. 7.

Referring again to FIG. 7, a pedestal assembly 460 is provided. The pedestal assembly 460 serves to support a substrate during processing. The pedestal assembly 460 includes not only the heater plate 462, but also a shaft 468, a pin lift 464 and a lift hoop 466 disposed there around. The pin lift 464 and lift hoop 466 aide in selectively raising the wafer above the heater plate 462. Pin holes 467 are disposed within the heater plate 462 to receive lift pins (not shown).

It is understood that the chamber 400 of FIG. 7 is illustrative, and that the improvements to the top liner in accordance with the present disclosure are viable in any deposition chamber capable of performing CVD or PECVD. Thus, other embodiments of the present disclosure may be provided. For example, the pumping liner 410 may have an inner diameter that is smaller than the inner diameter of the C-channel liner 420. This reduced dimension for the pumping liner 410 serves to reduce the inner diameter of the pumping port 405, thereby increasing velocity of gases moving out of the inner chamber 404 and through the pumping port 405. Increased gas velocity is desirable, as it reduces opportunities for carbonaceous residue buildup on chamber surfaces. It is also desirable that the liners be fabricated from a material having a highly smooth surface. This serves to reduce amorphous carbon deposition from accumulating on the surface. Examples of such material again include polished aluminum, polymer coating, Teflon, ceramics, and quartz.

It is also noted that carbon builds up on colder surfaces faster than on warmer surfaces. Because of this phenomenon, carbon tends to preferentially build up on the pumping system associated with the deposition chamber. The pumping systems are preferably heated to a temperature greater than 80° C. to reduce preferential build-up. Alternatively, or in addition, a cold trap can be integrated into the pumping system to collect unreacted carbon by-product. The cold trap can be cleaned or replaced at regular maintenance intervals.

Referring to FIG. 8, as described above pumping liner 410 includes a plurality of apertures 412 passing through a body 814 of pumping liner 410. Body 814 includes an inner circumferential surface 816 extending between upper surface area 810 and lower surface area 812. Body also includes an outer circumferential surface 818 extending between upper surface area 810 and lower surface area 812. Apertures 412 pass through body 814 between inner circumferential surface 816 and outer circumferential surface 818. As described below in more detail with reference to FIGS. 9 and 10, in accordance with some embodiments of the present disclosure, spacing between apertures 412 that are adjacent (i.e., next to) to each other is unequal or uneven. Spacing between adjacent apertures as used in the present disclosure refers to a distance between a centerline of a pair of two adjacent apertures as measured along the inner circumferential surface 816 or outer circumferential surface 818 of pumping liner 410. Unequal or uneven spacing refers to a situation when a distance between a centerline of a first pair of two adjacent apertures as measured along the inner circumferential surface 816 or outer circumferential surface 818 of pumping liner 410 is different than a distance between the centerline of a second pair of two adjacent apertures as measured along the inner circumferential surface 816 or outer circumferential surface 818 of pumping liner 410. Alternatively, in accordance with embodiments of the present disclosure, unequal or uneven spacing between a centerline of two adjacent apertures means a pitch between a centerline of a first pair of two adjacent apertures and a pitch between the centerline of a second pair of two adjacent apertures is different.

Referring to FIG. 9, an exhaust port 910 is schematically illustrated near the top of the illustrated pumping liner 410. Exhaust port 910 serves as a conduit through which process gas which has passed from the processing chamber 200 through apertures 412 of pumping liner 410 and into channel portion 425 can be exhausted from channel portion 425. Referring to FIG. 10, aperture 1016 is illustrated as being the closet aperture to exhaust port 910. In the embodiment of FIG. 10, aperture 1016 is closer to exhaust port 910 than apertures 1018, 1020 and 1022. Similarly, aperture 1016 is closer to exhaust port 910 than apertures 1030, 1032 and 1034.

Referring to FIG. 10, a pitch between adjacent apertures refers to the central angle 1013 (angle formed by two radii 1015 and 1017 with the vertex being at the center 1019 of the circular pumping liner 410) formed by the centerlines of adjacent apertures 1032 and 1034 and the center of the circular pumping liner 410. A pitch between adjacent apertures 1016 and 1018 is identified by reference numeral 1010. A pitch between adjacent apertures 1018 and 1020 is identified by reference numeral 1012. A pitch between adjacent apertures 1020 and 1022 is identified by reference numeral 1014. Changes in the central angle 1013 result in proportional changes in the intercepted minor arcs 1021 and 1023 defined by the arc between the centerlines of adjacent apertures 1032 and 1034 as measured on the respective outer circumferential surface 818 and inner circumferential surface 816.

Referring to FIGS. 9 and 10, the following description of the unequal or uneven spacing between adjacent apertures in accordance with embodiments described herein is provided with reference to the unequal pitch between adjacent apertures; however, the description applies equally to the distance between adjacent apertures as measured along the inner circumferential surface 816 or the outer circumferential surface 818 of pumping liner 410. In accordance with embodiments of FIG. 10, a pitch 1010 between first aperture 1016 and second aperture 1018 (which are adjacent to each other) defining first aperture pair 1024 is unequal to a pitch 1012 between second aperture 1018 and third aperture 1020 (which are adjacent to each other) defining second aperture pair 1026, which is adjacent to (directly next to) the first aperture pair 1024. In accordance with embodiments of the present disclosure, the pitch 1012 between second aperture 1018 and third aperture 1020 defining second aperture pair 1026 is unequal to the pitch 1014 between third aperture 1020 and fourth aperture 1022 defining third aperture pair 1028. In accordance with some embodiments of the present disclosure, an amount by which pitch 1010 differs from pitch 1012 and an amount pitch 1012 differs from pitch 1014 are equal. In other words, in accordance with embodiments of the present disclosure where pitch 1014 is less than pitch 1012 which is less than pitch 1010, the amount by which pitch 1012 is less than pitch 1010 is equal to the amount pitch 1014 is less than pitch 1012. Stated differently, in accordance with some embodiments of the present disclosure, the spacing between adjacent apertures 412 of pumping linear 410 decreases at regular intervals as the apertures become further removed from exhaust port to the point where an aperture that is furthest from exhaust port 910 is reached, (e.g., aperture 912 in FIGS. 9 and 10). At such point the spacing between adjacent apertures 412 of pumping linear 410 increase at regular intervals as the apertures become closer to exhaust port 910. In accordance with other embodiments of the present disclosure, spacing between adjacent apertures 412 of pumping linear 410 can increase at regular intervals as the apertures become further removed from exhaust port 910 to the point where an aperture that is furthest from exhaust port 910 is reached (e.g., aperture 912 in FIG. 9). In accordance with such alternative embodiments, at such point the spacing between adjacent apertures 412 of pumping linear 410 decreases at regular intervals as the apertures become closer to exhaust port 910. Examples of regular intervals by which the spacing between adjacent apertures increases or decreases include 0.05°, 0.1°, 0.2°, 0.3°, 0.4°, 0.5° or more, with 0.4° providing desired process gas velocity and process gas pressure profiles within the processing chamber. The relative inequality of spacing between adjacent apertures of a pumping liner is in accordance with embodiments of the present invention is chosen to affect the velocity profile of process gases within the processing chamber and the pressure profile of the process gases within the processing chamber to be more uniform across the work piece surface in the processing chamber compared to when spacing of apertures around the circumference of the pumping liner are equal. Embodiments of the present disclosure are not limited to a pumping liner where spacing between adjacent apertures increases or decreases at intervals. The regular intervals by which the spacing between adjacent apertures increases or decreases can differ from the described specific angular regular intervals. Described mathematically, the pitch between adjacent apertures of a first aperture pair is X degrees (°) and a pitch between adjacent apertures of a second aperture pair that is adjacent to the first aperture pair (e.g., first aperture pair 1024 and second aperture pair 1026 or second aperture pair 1026 and third aperture pair 1028) is X−0.05° to 0.5°. In other embodiments, the pitch between adjacent apertures of a first aperture pair is X degrees (°) and a pitch between adjacent apertures of a second aperture pair that is adjacent to the first aperture pair (e.g., first aperture pair