BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a pressure control system, especially for a pressure control system of a wafer polishing apparatus.

2. Description of Related Art

As shown in FIG. 1, a traditional pressure control system of a wafer polishing apparatus includes a main input air pressure regulator 1a, an air branch conduit 2a, a plurality of air pipes 3a, and a plurality of air pressure controlling devices 4a. The air branch conduit 2a is connected with the main input air pressure regulator la, one end of each of air pipes 3a is connected with the air branch conduit 2a, another end of each of air pipes 3a has a plurality of branches 31a connected with the air pressure controlling devices 4a respectively, and the air pressure controlling devices 4a are for controlling the pressure outputted from a polishing head of the wafer polishing apparatus to a wafer.

In order to making the pressure outputted from each of polishing heads to the wafer is high enough, ideally the pressure value inputted to each of the air pressure controlling devices 4a should be maintained to be 25 psi, so that the quality of polishing the wafer can be ensured. In fact because the branches 31a are connected with each other, leaping air phenomenon is happened between the air pressure controlling devices 4a and the pressure values of the air pressure controlling devices 4a are not the same, some pressure values are higher than 25 psi, and others are lower than 25 psi. When the pressure value of the air pressure controlling device 4a is lower than 25 psi, the wafer will leave out the wafer polishing apparatus. However, when the pressure value of the air pressure controlling device 4a is higher than 30 psi to exceed the rated pressure of the air pressure controlling device 4a, the air pressure controlling devices 4a is damaged and the life of the air pressure controlling device 4a is reduced.

Hence, the inventors of the present invention believe that the shortcomings described above are able to be improved and finally suggest the present invention which is of a reasonable design and is an effective improvement based on deep research and thought.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a pressure control system of a wafer polishing apparatus, and the pressure control system increase the yield of polishing wafers, and prevent the wafer polishing apparatus from being damaged.

To achieve the above object, the present invention provides a pressure control system of a wafer polishing apparatus. The pressure control system includes a main input air pressure regulator, an air branch conduit, a plurality of first pipes, a plurality of auxiliary air pressure regulators, a plurality of second pipes, and a plurality of air pressure controlling devices. The air branch conduit is connected with the main input air pressure regulator. The first pipes are connected between the air branch conduit and the auxiliary air pressure regulators. The second pipes are connected between the auxiliary air pressure regulators and the air pressure controlling devices.

The advantages of the present invention are described below: the auxiliary air pressure regulators can control the pressure of each of the second pipes, so that the air-leakage phenomenon is not happened between the air pressure controlling devices, and the stability of each of the air pressure controlling devices is higher and the yield of polishing wafers is increased. Besides, the auxiliary air pressure regulators can maintain the air pressure of each of the second pipes to be in the normal rated range, the auxiliary air pressure regulators can prevent the air pressure inputting to the air pressure controlling apparatus from being too high, so that increases the life of the air pressure controlling apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is the framework of the pressure control system of the wafer polishing apparatus according to the related art.

FIG. 2 is the framework of the pressure control system of the wafer polishing apparatus according to the present invention.

FIG. 3 is a plan view of the pressure control system according to the present invention.

FIG. 4 is a perspective view of the auxiliary air pressure regulator according to the present invention.

FIG. 5 is a cross-sectional view of the auxiliary air pressure regulator according to the present invention.

FIG. 6 is another embodiment of the pressure control system according to the present invention.

FIG. 7 is a first view of the output pressure comparison between the air pressure controlling apparatus of the present invention and the air pressure controlling apparatus of the related art.

FIG. 8 is a second view of the output pressure comparison between the air pressure controlling apparatus of the present invention and the air pressure controlling apparatus of the related art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Refer to FIG. 2 and FIG. 3, the pressure control system of the wafer polishing apparatus includes a main input air pressure regulator 1, an air branch conduit 2, a plurality of first pipes 3, a plurality of auxiliary air pressure regulators 4, a plurality of second pipes 5, and a plurality of air pressure controlling devices 6. The air branch conduit 2 is connected to the main input air pressure regulator 1, one end of each of the first pipes 3 is connected to the air branch conduit 2, and the air branch conduit 2 makes the main input air pressure regulator 1 outputs 25 psi pressure to each of the first pipe 3. Another end of each of the first pipes 3 which is apart from the air branch conduit 2 has a plurality of branches 31, the branches 31 are connected with the auxiliary air pressure regulators 4 respectively, two ends of each of the second pipes 5 are connected between each of the auxiliary air pressure regulators 4 and each of the air pressure controlling devices 6, and the air pressure controlling devices 6 can control a pressure outputted from a polishing head 7 of the wafer polishing apparatus to a surface of a wafer.

Refer to FIG. 4 and FIG. 5, each of the auxiliary air pressure regulators 4 includes a body 41, an air intake pipe 42, and an air outtake pipe 43, and the body 41 has a first pressure chamber 411, a second pressure chamber 412 and an air valve 413 formed therein. The air intake pipe 42 is connected with the body 41 and the branches 31(shown in FIG. 2), and the air intake pipe 42 is connected with the first pressure chamber 411. The air outtake pipe 43 is connected with the body 41 and the second pipes 5 (shown in FIG. 2), and the air outtake pipe 43 is connected with the second pressure chamber 412. When the air of the first pressure chamber 414 flows to the second pressure chamber 412, the air of the first pressure chamber 414 must pass through an air hole 414 firstly. The air valve 413 is mounted inside the body 41, and the air valve 413 has a first spring 4131. When the first spring 4131 moves upwardly, the air valve 413 stuffs the air hole 414 to stop the air of the first pressure chamber 414 flowing to the second pressure chamber 412.

A first manometer 44 and a second manometer 45 are connected with the body 41, the first manometer 44 connects with the first pressure chamber 411, the second manometer 45 connects with the second pressure chamber 412, and the first manometer 44 and the second manometer 45 can display the air pressure of the first pressure chamber 411 and the air pressure of the second pressure chamber 412.

An upside of the body 41 is connected with a top cover 46, a receiving chamber 461 is mounted inside the top cover 46, a knob 47 is screwed with the upside of the top cover 46, wherein the knob 47 has a screw 471, the screw 471 is screwed with the upside of the top cover 46 and inserts into the receiving chamber 461. A second spring 462 is mounted inside the receiving chamber 461, a first washer 463 is connected between an upside of the second spring 462 and the screw 471, and the screw 471 presses on the first washer 463.

A colloid film 48 is arranged between an underside of the top cover 46 and the body 41, a second washer 481 is connected between an underside of second spring 462 and the colloid film 48, and the second spring 462 presses on the second washer 481.

When the knob 47 is rotated by a user, the screw 471 will press on the second spring 462, so that the vertical position of the second washer 481 can be controlled. When the pressure outputted from the second spring 462 which is up to the second washer 481 is higher than the air pressure of the first pressure chamber 411 and the air pressure of the second pressure chamber 412, the air valve 413 will be moved downwardly via the second spring 462 and the air hole 414 will be opened. On contrary, when the pressure outputted from the second spring 462 which is up to the second washer 481 is lower than the air pressure of the first pressure chamber 411 and the air pressure of the second pressure chamber 412, the air valve 413 will be moved upwardly via the first spring 4131 and the air hole 414 will be closed, so that the air pressure of second pressure chamber 412 can be regulated via controlling the state (open/close) of the air hole 414.

As shown in FIG. 6, another embodiment of the present invention is presented, each of the auxiliary air pressure regulators 4 has one air intake pipe 42 and a plurality of air outtake pipes 43, the air intake pipes 42 are connected with the first pipes 3 respectively, and the outtake pipes 43 are connected with the second pipes 5 respectively.

As shown in FIG. 7, when the air pressure outputted from the main input air pressure regulator 1 is 30 psi, a user regulates the auxiliary air pressure regulators 4 to control the pressure value of each of the air pressure controlling devices 6 outputted to a polishing head 7. The pressure values are controlled by the auxiliary air pressure regulators 4 to be not over the steady state pressure value seriously (as shown in solid line), but the pressure value controlled by the pressure control system of the related art is over the steady state pressure value (as shown in dash line).

As shown in FIG. 8, when the air pressure outputted from the main input air pressure regulator 1 is decreased from 30 psi to 25 psi, the auxiliary air pressure regulators 4 can regulate the output pressure from each of the air pressure controlling devices 6 to maintain to be a steady state value (as shown in dash line), but the output pressure from the air pressure controlling device of the related art is decreased (as shown in solid line).

The advantages of the pressure control system of the present invention are described below:

1. The auxiliary air pressure regulator 4 controls the pressure of each of the second pipes 5, so that the air-leakage phenomenon is not happened between the air pressure controlling apparatuses 6 via the auxiliary air pressure regulators 4, the auxiliary air pressure regulator 4 can control air pressure of each of the second pipes 5 to maintain to be in a steady state value, even if the air pressure outputted from the main input pressure regulator 1 is changed, the output pressure from the air pressure controlling apparatus 6 will not be changed seriously, so that the stability of each air pressure controlling apparatus 6 is higher and the yield of polishing wafers is increased.

2. The auxiliary air pressure regulator 4 controls the pressure of each of the second pipes 5, so that each of the air pressure controlling device 6 is capable of outputting enough pressure to the polishing head 7, so that the polishing head 7 can output enough pressure to the wafer and the wafer can't leave out the polishing apparatus during a polishing process.

3. The pressure of each of the second pipes 5 can be controlled in the rated pressure range of the air pressure controlling device 6, so that the auxiliary air pressure regulators 4 can prevent the pressure of each of the air pressure controlling apparatuses 6 from being too high, so that the life of each of the air pressure controlling apparatuses 6 can be increased.

What are disclosed above are only the specification and the drawings of the preferred embodiment of the present invention and it is therefore not intended that the present invention be limited to the particular embodiment disclosed. It will be understood by those skilled in the art that various equivalent changes may be made depending on the specification and the drawings of the present invention without departing from the scope of the present invention.