CN210499744U

CN210499744U - Pressure control device and chemical mechanical polishing device

Info

Publication number: CN210499744U
Application number: CN201920720791.3U
Authority: CN
Inventors: 许振杰; 王春龙; 赵德文
Original assignee: Tsinghua University; Huahaiqingke Co Ltd
Current assignee: Tsinghua University; Huahaiqingke Co Ltd
Priority date: 2019-05-18
Filing date: 2019-05-18
Publication date: 2020-05-12
Anticipated expiration: 2029-05-18

Abstract

The utility model relates to a chemical mechanical polishing technical field discloses a pressure control device and chemical mechanical polishing device. The pressure control device comprises a pressure control module and a first pressure sensor, wherein a positive pressure control unit and a negative pressure control unit are integrated in the pressure control module; the input end of the positive pressure control unit is connected with a positive pressure supply source, the input end of the negative pressure control unit is connected with a negative pressure supply source, and the output end of the positive pressure control unit and the output end of the negative pressure control unit are connected with a terminal element together; the first pressure sensor is connected to the gas path port of the terminal element; the positive pressure control unit, the negative pressure control unit and the first pressure sensor are respectively connected with the controller; the controller acquires the port pressure of the terminal element acquired by the first pressure sensor and controls the switch of the positive pressure control unit and/or the negative pressure control unit so as to stabilize the port pressure at a preset target pressure. The chemical mechanical polishing apparatus includes a pressure control device in gas communication with a pressure chamber within the carrier head.

Description

Pressure control device and chemical mechanical polishing device

Technical Field

The utility model relates to a chemical mechanical polishing technical field especially relates to a pressure control device and chemical mechanical polishing device.

Background

Chemical Mechanical Planarization (CMP) is a global surface Planarization technique used in semiconductor manufacturing processes to reduce the effects of wafer thickness variations and surface topography. Since CMP can precisely and uniformly planarize a wafer to a desired thickness and flatness, it has become one of the most widely used surface planarization techniques in semiconductor manufacturing.

The CMP process is realized by the following steps: the carrier head holds the wafer and rotates and horizontally reciprocates at a certain speed, a certain downward pressure is applied to press the wafer on the rotating polishing pad, polishing solution consisting of submicron or nanometer abrasive particles and chemical solution flows between the wafer and the polishing pad, the polishing solution is uniformly distributed under the action of transmission and rotating centrifugal force of the polishing pad to form a layer of liquid film between the wafer and the polishing pad, chemical components in the liquid chemically react with the wafer to convert insoluble substances into easily soluble substances, then the chemical reactants are removed from the surface of the wafer through micro-mechanical friction of the abrasive particles and dissolved in the flowing liquid to be taken away, namely surface materials are removed in the alternate process of chemical film forming and mechanical film removing to realize surface planarization treatment, so that the aim of global planarization is fulfilled.

The lower part of the bearing head is provided with a pressure chamber formed by an elastic membrane, pressurized gas is supplied into the pressure chamber, and the acting force among the bearing head, the wafer and the polishing pad is adjusted by the pressure in the pressure chamber.

In conclusion, the prior art has the problem of inaccurate pressure control.

SUMMERY OF THE UTILITY MODEL

An embodiment of the utility model provides a pressure control device and chemical mechanical polishing device aims at solving one of the technical problem that exists among the prior art at least.

The utility model provides a first aspect provides a pressure control device for chemical mechanical polishing, including pressure control module and first pressure sensor, integrated malleation the control unit and the negative pressure the control unit in the pressure control module.

The input end of the positive pressure control unit is connected with a positive pressure supply source, the input end of the negative pressure control unit is connected with a negative pressure supply source, and the output end of the positive pressure control unit and the output end of the negative pressure control unit are connected with a terminal element together; the first pressure sensor is connected to the gas path port of the terminal element; the positive pressure control unit, the negative pressure control unit and the first pressure sensor are respectively connected with a controller; the controller acquires the port pressure of the terminal element acquired by the first pressure sensor and controls the switch of the positive pressure control unit and/or the negative pressure control unit so that the port pressure is stabilized at a preset target pressure.

In one embodiment, the pressure control device further comprises a first solenoid valve disposed on the terminal element pneumatic circuit.

In one embodiment, the first solenoid valve is a three-way solenoid valve.

In one embodiment, the pressure control device further comprises a second solenoid valve disposed on the terminal element gas path.

In one embodiment, the second solenoid valve is a two-way solenoid valve.

In one embodiment, a second pressure sensor is further integrated in the pressure control module, and the second pressure sensor is connected with the output ends of the positive pressure control unit and the negative pressure control unit.

In one embodiment, the pressure control device further comprises a flow sensor connected to the output ends of the positive pressure control unit and the negative pressure control unit, and the flow sensor is connected to the controller, so that the controller can determine whether gas leaks from the gas path by using the flow value detected by the flow sensor.

In one embodiment, the terminal element is a pressure chamber formed by an elastic membrane at the lower part of the carrier head.

In one embodiment, the terminal element is a pressurized chamber of a dresser.

A second aspect of the embodiments of the present invention provides a chemical mechanical polishing apparatus, including:

a polishing disk covered with a polishing pad for polishing a wafer;

the bearing head is used for holding a wafer and pressing the wafer on the polishing pad; and

the pressure control device is connected with the pressure chamber in the carrier head through a gas circuit.

In one embodiment, the chemical mechanical polishing apparatus further comprises:

the dresser is used for dressing the surface appearance of the polishing pad; and

the pressure control device is connected with the pressurizing chamber in the dresser in an air path.

The application pressure control device and chemical mechanical polishing device, its beneficial effect includes: the positive pressure adjustment and the negative pressure adjustment can be simultaneously realized, and the positive pressure or the negative pressure can be accurately controlled, so that the accurate required pressure is obtained.

Drawings

The advantages of the invention will become clearer and more easily understood from the detailed description given with reference to the following drawings, which are given purely by way of illustration and do not limit the scope of protection of the invention, wherein:

fig. 1 is a schematic structural diagram of a chemical mechanical polishing apparatus according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a carrier head according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a pressure control device according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a pressure control device connected to a carrier head according to an embodiment of the present invention;

description of reference numerals:

10. a carrier head; 11. a superstructure; 12. a lower structure; 121. a base; 122. a retaining ring; 123. an elastic film; 13. a flexible connector; z1, 1 st pressure chamber; z2, 2 nd pressure chamber; z3, No. 3 pressure chamber; z4, 4 th pressure chamber; f1, a first air path; f2, a second air path; f3, a third air path; f4, a fourth gas path;

20. a polishing disk; 21. a polishing pad;

30. a liquid supply device;

40. a finisher; 41. a base; 42. swinging arms; 43. trimming the head; 431. a rough surface;

50. a pressure control device; 501. a pressure control module; 51. a positive pressure control unit; 52. a negative pressure control unit; 53. a first pressure sensor; 54. a first solenoid valve; 55. a second solenoid valve; 56. a second pressure sensor; 57. a flow sensor.

Detailed Description

The technical solution of the present invention will be described in detail with reference to the following embodiments and accompanying drawings. The embodiments described herein are specific embodiments of the present invention and are provided to illustrate the concepts of the present invention; the description is intended to be illustrative and exemplary and should not be taken to limit the scope of the invention. In addition to the embodiments described herein, those skilled in the art will be able to employ other technical solutions which are obvious based on the disclosure of the claims and the specification thereof, and these technical solutions include technical solutions which make any obvious replacement or modification of the embodiments described herein. It is to be understood that, unless otherwise specified, the following descriptions of specific embodiments of the present invention are made for ease of understanding in a natural state where the relevant devices, apparatuses, components, etc. are originally at rest and are not given external control signals and driving forces.

As shown in fig. 1, a chemical mechanical polishing apparatus includes a carrier head 10 for holding a wafer, a polishing pad 20 covered with a polishing pad 21, and a liquid supply device 30 for supplying a polishing liquid to a surface of the polishing pad 21. During the polishing of the wafer, the carrier head 10 absorbs the wafer and then presses the wafer against the polishing pad 21 to drive the wafer to rotate and horizontally reciprocate, and the polishing pad 20 drives the polishing pad 21 to rotate, so that the wafer and the polishing pad 21 are rubbed by the relative motion of the carrier head 10 and the polishing pad 20 under the chemical action of the polishing solution to perform polishing.

Fig. 2 is a schematic structural diagram of a carrier head 10. The carrier head 10 comprises an upper structure 11 and a lower structure 12, the upper structure 11 being connected to the drive shaft of the carrier head, the upper structure 11 and the lower structure 12 being connected by a flexible connection 13. The lower structure 12 includes a base 121, an elastic membrane 123, and a retaining ring 122. The superstructure 11 is secured to the upper end of the flexible connector 13 and the base 121 is secured to the lower end of the flexible connector 13. The elastic membrane 123 and the retaining ring 122 are both fixed on the lower surface of the base 121, and the annular retaining ring 122 is located outside the elastic membrane 123 and is disposed around the elastic membrane 123. The elastic membrane 123 is used to adsorb and apply a downward pressure to the wafer, and the elastic membrane 123 may be made of an elastic material, for example, chloroprene or silicone rubber. The retaining ring 122 serves to retain the wafer under the elastic membrane 123 to prevent the wafer from slipping out.

As shown in fig. 2, the elastic membrane 123 is provided with a plurality of concentric pressure chambers inside, and is described by taking 3 pressure chambers as an example in fig. 2, and the 1 st pressure chamber Z1, the 2 nd pressure chamber Z2 and the 3 rd pressure chamber Z3 are respectively concentrically provided in this order from the center to the outside. The central 1 st pressure chamber Z1 is circular, and the 2 nd pressure chamber Z2 and the 3 rd pressure chamber Z3 are concentric rings. It is obvious that the number of pressure chambers shown in fig. 2 is only an example, but in practice other numbers are possible, such as 4, 5, 6, 7, etc.

Pressurized gas is supplied to the 1 st, 2 nd and 3 rd pressure chambers Z1, Z2 and Z3 from a positive pressure supply source via first, second and third gas paths F1, F2 and F3, respectively. In addition, negative pressure is formed in the 1 st, 2 nd and 3 rd pressure chambers Z1, Z2 and Z3 by the negative pressure supply source through the first, second and third air passages F1, F2 and F3, respectively. The negative pressure supply may be a vacuum source.

The internal pressures of the 1 st, 2 nd and 3 rd pressure chambers Z1, Z2 and Z3 are independent and can be varied, respectively, and accordingly, the different pressure chambers of the carrier head 10 divide the wafer surface into a plurality of corresponding partitions, thereby enabling the polishing pressures of the three regions corresponding to the wafer, i.e., the central, middle and peripheral regions of the wafer surface, to be independently adjusted. Each pressure chamber can apply different pressures to the corresponding wafer surface subarea, and different pressures can be applied to different wafer surface subareas by respectively controlling the pressure of fluid such as pressurized air supplied to the pressure chambers.

Further, by raising and lowering the entire carrier head 10, the retainer ring 122 can be pressed against the polishing pad 21 with a predetermined pressure. A 4 th pressure chamber Z4 is formed between the upper structure 11 and the lower structure 12, and the flexible connecting element 13 is extended and contracted by controlling the pressure in the 4 th pressure chamber Z4 to move the lower structure 12 up and down relative to the upper structure 11. Pressurized gas may be supplied from a positive pressure supply source into the 4 th pressure chamber Z4 via a fourth gas path F4 to move the lower structure 12 downward, and negative pressure may be formed in the 4 th pressure chamber Z4 from a negative pressure supply source via a fourth gas path F4 to move the lower structure 12 upward. Thereby, the entire lower structure 12 composed of the base 121, the elastic membrane 123, and the retaining ring 122 can be moved in the up-down direction.

During wafer polishing, the carrier head 10 presses the wafer against the polishing pad 21 and the carrier head 10 performs horizontal reciprocating movement in the radial direction of the polishing platen 20 (as indicated by the line with the double-headed arrow in fig. 1), and at the same time, the carrier head 10 and the polishing platen 20 perform synchronous rotational movement, so that the surface of the wafer in contact with the polishing pad 21 is gradually polished. The peripheral end of the wafer is surrounded by a retaining ring 122 so that the wafer does not fly out of the lower portion of the carrier head 10 during polishing.

The first air passage F1, the second air passage F2, the third air passage F3, and the fourth air passage F4, which communicate with the 1 st pressure chamber Z1, the 2 nd pressure chamber Z2, the 3 rd pressure chamber Z3, and the 4 th pressure chamber Z4, are respectively provided with a pressure control device 50.

As shown in fig. 3, an embodiment of the present invention provides a pressure control apparatus 50 for chemical mechanical polishing, including a pressure control module 501 and a first pressure sensor 53, wherein a positive pressure control unit 51 and a negative pressure control unit 52 are integrated in the pressure control module 501.

The input end of the positive pressure control unit 51 is connected with a positive pressure supply source, the input end of the negative pressure control unit 52 is connected with a negative pressure supply source, and the output end of the positive pressure control unit 51 and the output end of the negative pressure control unit 52 are connected with a terminal element; the first pressure sensor 53 is connected to the gas path port of the terminal element; the positive pressure control unit 51, the negative pressure control unit 52 and the first pressure sensor 53 are respectively connected with a controller; the controller acquires the port pressure of the terminal element acquired by the first pressure sensor 53, and controls the opening and closing of the positive pressure control unit 51 and/or the negative pressure control unit 52 so that the port pressure is stabilized at a preset target pressure.

As shown in fig. 3, the positive pressure control unit 51 and the negative pressure control unit 52 are integrated into an integrated structure, i.e., a pressure control module 501. The integrated design can shorten the length of the pipeline between the control units, reduce the volume of the pressure control device, and simultaneously, the pipeline shortens to ensure that the pressure control response speed is higher, so that the preset target pressure can be reached more quickly.

The pressure control module 501 can adopt a piezoelectric proportional valve which controls the deformation of piezoelectric ceramics through voltage to realize ventilation proportional control, and has the characteristics of low power consumption and no heat generation.

In this embodiment, the input end of the positive pressure control unit 51 is connected to a positive pressure supply source (i.e. a positive pressure source), the output end is connected to the air path of the pressure chamber, and the input end of the control signal is connected to the controller, so that the positive pressure control unit 51 switches on or off the air path between the positive pressure supply source and the terminal element under the control of the controller, so as to introduce pressurized gas into the terminal element and increase the pressure in the terminal element.

The negative pressure control unit 52 has an input terminal connected to a negative pressure supply source (i.e., a negative pressure source), an output terminal connected to the air path of the terminal element, and a control signal input terminal connected to the controller, so that the negative pressure control unit 52 switches on or off the air path between the negative pressure supply source and the terminal element under the control of the controller to draw out gas from the terminal element and reduce the pressure in the terminal element.

The output end of the positive pressure control unit 51 and the output end of the negative pressure control unit 52 are connected to the air path of the terminal element.

The first pressure sensor 53 is disposed at a position of the air path port of the terminal member near the terminal member to accurately measure the pressure inside the terminal member and output an external pressure signal to the controller. The controller obtains the pressure in the terminal element according to the external pressure signal.

The controller is a PID controller.

The working principle of the pressure control device 50 in the present embodiment is as follows:

when the positive pressure control unit 51 is used to introduce air from the first tiny positive pressure to the terminal element, the second tiny positive pressure is smaller than the first tiny positive pressure, for example, 0.1psi air pressure is introduced first and then reduced to 0.05psi, because the electric control valve has uncontrollable pressure in a tiny range when approaching zero pressure, the negative pressure control unit 52 can be used for pressure compensation, the negative pressure control unit 52 is controlled to be opened for a certain time, and when the first pressure sensor 53 detects that the air pressure in the terminal element reaches a preset target pressure, the negative pressure control unit 52 and the positive pressure control unit 51 are closed.

When a slight positive pressure, for example 0.05psi, is applied to the terminal element by the positive pressure control unit 51, the slight negative pressure can be applied by the negative pressure control unit 52 for pressure compensation after the allowable range of the positive pressure is reached, so as to obtain an accurate slight positive pressure.

When the negative pressure control unit 52 is used to increase the first tiny negative pressure in the terminal element to the second tiny negative pressure, the second tiny negative pressure is larger than the first tiny negative pressure, for example, the air pressure is firstly introduced to-0.1 psi and then increased to-0.05 psi, at this time, the positive pressure control unit 51 can be used for pressure compensation, the positive pressure control unit 51 is controlled to be opened for a certain time, and when the air pressure in the terminal element detected by the first pressure sensor 53 reaches the preset target pressure, the positive pressure control unit 51 and the negative pressure control unit 52 are closed.

When a slight negative pressure, for example, -0.05psi, is drawn from the terminal member by the negative pressure control unit 52, it is also possible to compensate the pressure by the positive pressure control unit 51 by supplying a slight positive pressure after the negative pressure allowable pressure range is reached, so as to obtain a precise slight negative pressure.

The embodiment of the utility model provides a can realize malleation adjustment and negative pressure adjustment simultaneously, can carry out accurate pressure control to malleation or negative pressure well to obtain accurate required pressure.

In one embodiment, the controller controlling the switch of the positive pressure control unit 51 and/or the negative pressure control unit 52 can be realized by two ways: the pressure at the valve output may be controlled by controlling the opening degree of the positive pressure control unit 51 or the negative pressure control unit 52, and may also be controlled by controlling the on-off duty ratio of the positive pressure control unit 51 or the negative pressure control unit 52.

For the tiny air pressure close to zero pressure, the traditional proportional valve has a tiny range which is not controllable, and the embodiment can obtain a more accurate controllable range close to zero pressure through the positive and negative pressure parts of the piezoelectric proportional valve.

In one embodiment, as shown in FIG. 3, the pressure control device 50 further includes a first solenoid valve 54 disposed on the terminal element pneumatic circuit.

The first solenoid valve 54 is a three-way solenoid valve, and is used for switching, so that the air path of the terminal element can be communicated with the output ends of the positive pressure control unit 51 and the negative pressure control unit 52, or the air path of the terminal element can be communicated with the ambient atmospheric pressure.

In one embodiment, as shown in FIG. 3, the pressure control device 50 further includes a second solenoid valve 55 disposed on the terminal element pneumatic circuit.

The second electromagnetic valve 55 is a two-way electromagnetic valve and is used for controlling the on-off of the gas path of the terminal element.

The output end of the positive pressure control unit 51 and the output end of the negative pressure control unit 52 are commonly connected to the input end of the first electromagnetic valve 54, the output end of the first electromagnetic valve 54 is connected to the input end of the second electromagnetic valve 55, and the output end of the second electromagnetic valve 55 is connected to the gas path port of the terminal element.

In one embodiment, as shown in fig. 3, a second pressure sensor 56 is further integrated in the pressure control module 501, and the second pressure sensor 56 is connected to the output terminals of the positive pressure control unit 51 and the negative pressure control unit 52.

The second pressure sensor 56 outputs an internal pressure signal to the controller, and the controller acquires output end pressures of the positive pressure control unit 51 and the negative pressure control unit 52 based on the internal pressure signal.

In one embodiment, as shown in fig. 3, the pressure control device 50 further includes a flow sensor 57 connected to the output ends of the positive pressure control unit 51 and the negative pressure control unit 52, and the flow sensor 57 is connected to the controller, so that the controller can determine whether there is gas leakage in the gas path by using the flow value detected by the flow sensor.

The flow sensor 57 is used to monitor the gas flow of the gas path in the polishing process step.

When one of the positive pressure control unit 51 and the negative pressure control unit 52 is opened and the other is closed, and simultaneously the first electromagnetic valve 54 and the second electromagnetic valve 55 are both opened, when the pressure detected by the first pressure sensor 53 reaches the preset target pressure, if the current flow detected by the flow sensor 57 is higher than the calibrated flow range, it is determined that gas leakage occurs. The calibration flow range is the required flow corresponding to the preset target pressure obtained by testing in advance by using a standard terminal element.

This embodiment has realized through using flow sensor that real-time on-line measurement flow has whether to have gas leakage in order to judge, can avoid gas leakage to pollute external environment, can also prevent to inhale liquid from the external world when bleeding and cause the pollution of terminal element.

As an embodiment, the terminal element is a pressure chamber formed by an elastic membrane 123 at the lower part of the carrier head 10.

The termination elements referred to herein may be various pressure chambers within the carrier head 10, such as the 1 st pressure chamber Z1, the 2 nd pressure chamber Z2, the 3 rd pressure chamber Z3, and/or the 4 th pressure chamber Z4.

As shown in fig. 4, the pressure control device 50 is connected to the air passage of the corresponding pressure chamber to independently control the air pressure in the pressure chamber through the air passage. The plurality of pressure control devices 50 are respectively connected with the first air passage F1 of the 1 st pressure chamber Z1, the second air passage F2 of the 2 nd pressure chamber Z2, the third air passage F3 of the 3 rd pressure chamber Z3 and the fourth air passage F4 of the 4 th pressure chamber Z4 in a one-to-one manner.

When the pressure chamber of the bearing head is pressurized or depressurized, the micro pressure can be accurately controlled.

As shown in fig. 1, the chemical mechanical polishing apparatus further includes a dresser 40 for dressing and activating the topography of the polishing pad 21. The dresser 40 includes a base 41, a swing arm 42, and a dressing head 43, and the dressing head 43 has a rough surface 431 such as a disk surface in which diamond grains are embedded. A motor is connected to the dresser 40 to drive the dresser 40 to swing. During polishing, the working process of the dresser 40 is: with the base 41 as the center, the swing arm 42 drives the dressing head 43 to swing to sweep the distance from the center to the edge of the polishing pad 21 (as shown by the curve with the double-headed arrow in fig. 1), and at the same time, the dressing head 43 carries the rough surface to rotate and applies a certain regular pressure on the polishing pad 21, thereby dressing and activating the surface topography of the polishing pad 21. The dresser 40 can remove foreign particles remaining on the surface of the polishing pad 21, such as abrasive particles in the polishing liquid and waste materials detached from the surface of the wafer, and can also flatten the surface deformation of the polishing pad 21 caused by the polishing, thereby ensuring the consistency of the surface topography of the polishing pad 21 during the polishing and stabilizing the polishing removal rate.

The dresser 40 has a closed cavity inside as a pressurizing chamber to achieve the up-and-down movement of the rough surface 431 by controlling the air pressure in the pressurizing chamber.

As another possible embodiment, the terminal element is a pressurizing chamber of the dresser 40, and the pressure control device 50 is connected to an air passage of the pressurizing chamber to control the air pressure in the pressurizing chamber.

This embodiment can realize accurate control of the minute pressure when the pressurizing chamber of the dresser is pressurized or depressurized.

When being close to the zero pressure, traditional proportional valve has small scope uncontrollable, the embodiment of the utility model provides a positive negative splenium of accessible piezoelectricity proportional valve is divided to close and is obtained the controllable scope of being closer to the zero pressure. When the positive pressure is adjusted to zero pressure, after the positive pressure reaches the allowable pressure range, the micro negative pressure is used for pressure compensation, so that the positive pressure is closer to zero pressure; when the negative pressure is adjusted to zero pressure, the micro positive pressure is used for pressure compensation after the negative pressure allowable pressure range is reached, so that the negative pressure is closer to zero pressure.

When the positive or negative pressure reaches a certain set value quickly, overshoot occurs during the settling process due to component detection and system response delays. The embodiment of the utility model provides an in when first pressure sensor detects pressure and reaches the setting value error interval, make controller control give short-term backpressure, the overshoot that the balanced system response time delay caused avoids pressure to transfinite and causes harm, makes system pressure rapid stabilization simultaneously.

The drawings in the present specification are schematic views to assist in explaining the concept of the present invention, and schematically show the shapes of the respective portions and the mutual relationships thereof. It should be understood that the drawings are not necessarily to scale, the same reference numerals being used to identify the same elements in the drawings in order to clearly illustrate the structure of the various elements of the embodiments of the invention.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A pressure control apparatus for chemical mechanical polishing includes a pressure control module having a positive pressure control unit and a negative pressure control unit integrated therein, and a first pressure sensor;

2. The pressure control device of claim 1, further comprising a first solenoid valve disposed on the terminal element pneumatic circuit.

3. The pressure control device of claim 2, wherein the first solenoid valve is a three-way solenoid valve.

4. The pressure control device of claim 1, further comprising a second solenoid valve disposed on the terminal element pneumatic circuit.

5. The pressure control device of claim 4, wherein the second solenoid valve is a two-way solenoid valve.

6. The pressure control device of claim 1, wherein a second pressure sensor is further integrated in the pressure control module, and the second pressure sensor is connected with the output ends of the positive pressure control unit and the negative pressure control unit.

7. The pressure control device according to claim 1, further comprising flow sensors connected to output ends of the positive pressure control unit and the negative pressure control unit, wherein the flow sensors are connected to the controller, so that the controller can determine whether gas leaks from the gas path by using flow values detected by the flow sensors.

8. Pressure control device as claimed in claim 1, characterized in that the terminating element is a pressure chamber formed by an elastic membrane in the lower part of the carrier head.

9. The pressure control device of claim 1, wherein the terminal element is a pressurized chamber of a dresser.

10. A chemical mechanical polishing apparatus comprising:

a polishing disk covered with a polishing pad for polishing a wafer;

a pressure control device as claimed in any one of claims 1 to 9 in pneumatic connection with a pressure chamber in the carrier head.

11. The chemical mechanical polishing apparatus as recited in claim 10, further comprising:

a pressure control device as claimed in any one of claims 1 to 9 in pneumatic connection with a pressurised chamber within the conditioner.