CN112045548A

CN112045548A - Wafer bearing device for chemical mechanical polishing and chemical mechanical polishing equipment

Info

Publication number: CN112045548A
Application number: CN202010858137.6A
Authority: CN
Inventors: 王春龙; 许振杰
Original assignee: Huahaiqingke Co Ltd
Current assignee: Huahaiqingke Co Ltd
Priority date: 2020-08-24
Filing date: 2020-08-24
Publication date: 2020-12-08
Anticipated expiration: 2040-08-24
Also published as: CN112045548B

Abstract

The invention discloses a wafer bearing device for chemical mechanical polishing and chemical mechanical polishing equipment, wherein the wafer bearing device comprises a bearing head and an upper pneumatic assembly; the upper pneumatic assembly comprises a first air path, a pressure sensor and a first electromagnetic valve, wherein the pressure sensor and the first electromagnetic valve are connected to a branch of the first air path; the upper pneumatic assembly is connected with the controller to control the first electromagnetic valve to be electrified in the wafer suction process of the bearing head to enable the pressure sensor to be quickly communicated with the atmosphere, so that the time of zero point calibration of the pressure sensor is shortened. The chemical mechanical polishing equipment comprises a wafer bearing device, a polishing disk, a trimmer and a polishing liquid supply device.

Description

Wafer bearing device for chemical mechanical polishing and chemical mechanical polishing equipment

Technical Field

The invention relates to the technical field of chemical mechanical polishing, in particular to a wafer bearing device for chemical mechanical polishing and chemical mechanical polishing equipment.

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 polishing pressure is not only one of the important process parameters influencing the material removal rate and the removal nonuniformity in the process, but also a key factor for realizing the actions of wafer unloading and the like before and after polishing. Pressure control relies on a pressure sensor to sense the pressure in the chamber to obtain a pressure value, and then to adjust to reach a target value based on the measured pressure value. Therefore, the accuracy of the output pressure value of the pressure sensor is very important. The pressure sensor has a zero offset problem, which makes the measurement inaccurate, and once the pressure sensor measures inaccurately, the pressure control effect is affected, and wafer fragments may be caused in severe cases. Therefore, zero point calibration of the pressure sensor is required. However, since it takes a certain time for the pressure in the chamber connected to the pressure sensor to change, it takes a long time to calibrate the zero point of the pressure sensor, and the productivity of the whole apparatus is reduced.

Disclosure of Invention

The embodiment of the invention provides a wafer bearing device for chemical mechanical polishing and chemical mechanical polishing equipment, and aims to at least solve one of the technical problems in the prior art.

A first aspect of an embodiment of the present invention provides a wafer carrier device for chemical mechanical polishing, including a carrier head and an upper pneumatic assembly;

the bearing head comprises an upper structure and a lower structure, the upper structure and the lower structure are connected through a flexible connecting piece, and a main pressure chamber is formed among the upper structure, the lower structure and the flexible connecting piece to control the pressure in the main pressure chamber so that the flexible connecting piece stretches and retracts to realize the up-and-down movement of the lower structure relative to the upper structure;

the upper pneumatic assembly comprises a first air path, and a pressure sensor and a first electromagnetic valve which are connected to a branch of the first air path, the first air path is connected between an air source and the main pressure chamber, the pressure sensor is used for detecting a pressure value in the main pressure chamber, and the pressure sensor is directly connected with an air path port of the main pressure chamber through the first electromagnetic valve so as to enable the branch to be communicated with the atmosphere without changing the pressure in the main pressure chamber when the pressure sensor corrects a zero point;

the upper pneumatic assembly is connected with the controller to control the first electromagnetic valve to be electrified in the wafer suction process of the wafer adsorbed by the bearing head, so that the pressure sensor is quickly communicated with the atmosphere, and the zero calibration time of the pressure sensor is shortened.

In one embodiment, the first electromagnetic valve is a two-position three-way electromagnetic valve, a normally open port of the first electromagnetic valve is directly communicated with an air path port of the main pressure chamber, a normally open port of the first electromagnetic valve is communicated with the atmosphere, and a common port of the first electromagnetic valve is connected with the pressure sensor.

In one embodiment, the first air circuit comprises a switch control module, two input ends of the switch control module are respectively connected with a positive pressure source and a negative pressure source, and an output end of the switch control module is connected with the main pressure chamber.

In one embodiment, the switch control module comprises a solenoid proportional valve for controlling the magnitude of the gas pressure, a second solenoid valve for positive and negative pressure switching, a third solenoid valve for venting to atmosphere, and a fourth solenoid valve for holding pressure.

In one embodiment, the second solenoid valve, the third solenoid valve and the fourth solenoid valve are two-position three-way solenoid valves.

In one embodiment, the first port of the electromagnetic proportional valve is connected with a positive pressure source, the second port of the electromagnetic proportional valve is connected with a normally-off port of the second electromagnetic valve, a normally-on port of the second electromagnetic valve is connected with a negative pressure source, a common port of the second electromagnetic valve is connected with a normally-off port of the third electromagnetic valve, a normally-on port of the third electromagnetic valve is communicated with the atmosphere, a common port of the third electromagnetic valve is connected with a normally-on port of the fourth electromagnetic valve, a normally-off port of the fourth electromagnetic valve is communicated with the atmosphere, and a common port of the fourth electromagnetic valve is communicated with the gas path port of the main pressure chamber.

In one embodiment, the substructure includes a gimbal, a base, an elastic membrane, and a retaining ring; the balancing stand is slidably arranged in the central through hole of the upper structure and can drive the base to move up and down, the elastic membrane is arranged on the bottom surface of the base, and the outer peripheral side of the elastic membrane is provided with a retaining ring connected with the bottom surface of the base.

In one embodiment, a preset number of concentric pressure chambers are arranged inside the elastic membrane, and the upper pneumatic assembly further comprises a preset number of air passages which are connected with the concentric pressure chambers in a one-to-one correspondence manner.

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

the wafer carrying device as described above;

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

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

and the polishing liquid supply device is used for distributing the polishing liquid on the surface of the polishing pad.

The embodiment of the invention has the beneficial effects that: through the break-make of control first solenoid valve, realize pressure sensor in to main pressure chamber pressure measurement and lead to the quick switch-over between the atmosphere two kinds of states, can solve pressure sensor on the one hand and appear inaccurate problem when proofreading zero point, on the other hand can shorten the consuming time of proofreading zero point, accomplishes pressure sensor proofreading process fast to improve whole equipment's productivity.

Drawings

The advantages of the invention will become clearer and more readily appreciated from the detailed description given with reference to the following drawings, which are given by way of illustration only 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;

FIGS. 3(a) to 3(c) are schematic views illustrating a wafer sucking process of a carrier head sucking a wafer;

FIG. 4 is a partial schematic view of an upper pneumatic assembly provided in accordance with an embodiment of the present invention.

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 for the purpose of illustrating the concepts of the 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 should be understood that, unless otherwise specified, the following description of the embodiments of the present invention is made for the convenience of understanding, and the description is made in a natural state where relevant devices, apparatuses, components, etc. are originally at rest and no external control signals and driving forces are given.

Further, it is also noted that terms used herein such as front, back, up, down, left, right, top, bottom, front, back, horizontal, vertical, and the like, to denote orientation, are used merely for convenience of description to facilitate understanding of relative positions or orientations, and are not intended to limit the orientation of any device or structure.

In order to explain the technical means of the present invention, the following description will be given by way of specific examples.

In the present invention, "wafer" may also be referred to as "wafer", and its meaning is equivalent to the actual function.

Fig. 1 is a schematic view showing the positions of a polishing unit 100 and a loading and unloading section 200 in a chemical mechanical polishing apparatus, the loading and unloading section 200 being disposed adjacent to the polishing unit 100 to facilitate the transportation of wafers.

The polishing unit 100 includes a carrier head 10, a polishing pad 20, a polishing pad 30, a dressing device 40, and a polishing liquid supply device 50; the polishing pad 30 is disposed on the upper surface of the polishing disk 20 and rotates therewith along the axis Ax 1; the carrier head 10 capable of moving horizontally is arranged above the polishing pad 30, and the lower surface of the carrier head attracts and holds a wafer W to be polished; the dressing device 40 comprises a dressing arm 41 and a dressing head 42, wherein the dressing arm 41 drives the rotating dressing head 42 to swing so as to dress the surface of the polishing pad 30 to a state suitable for polishing; the polishing liquid supply device 50 distributes the polishing liquid on the surface of the polishing pad 30; during the polishing operation, the carrier head 10 presses the surface of the wafer W to be polished against the surface of the polishing pad 30, and the polishing liquid is distributed between the polishing pad 30 and the wafer W, so as to remove the surface material of the wafer W under the action of the chemical mechanical process.

In chemical mechanical polishing, the operation process of each wafer mainly comprises:

1) the wafer suction process, also called loading, moves the carrier head 10 above the loading/unloading section and then sucks the wafer W placed on the loading/unloading section below the carrier head 10;

2) a polishing process, wherein the wafer W is carried on a polishing pad by the bearing head 10 for polishing;

3) the unloading process, also called unloading, is to carry the wafer W back by the carrier head 10 after polishing is completed and unload the wafer W onto the loading and unloading section.

In the present application, the carrier head 10 and an Upper Pneumatic Assembly 60 (UPA) constitute a wafer carrier 70 for chemical mechanical polishing.

Fig. 2 shows a block diagram of a carrier head 10, the carrier head 10 comprising an upper structure 11 and a lower structure 12, the upper structure 11 and the lower structure 12 being connected by a flexible connection 13. The superstructure 11 is connected to a carrier head drive shaft (not shown). The substructure 12 includes a gimbal 121, a base 122, an elastic membrane 123, and a retaining ring 124. The balance frame 121 is slidably disposed in the central through hole of the upper structure 11 and can drive the base 122 to move up and down. The elastic membrane 123 is provided on the bottom surface of the base 122, and a retaining ring 124 connected to the bottom surface of the base 122 is provided on the outer peripheral side of the elastic membrane 123. The elastic membrane 123 is used to adsorb the wafer W and apply downward pressure to the wafer W, and the elastic membrane 123 may be made of an elastic material, for example, chloroprene or silicon rubber. An annular retainer ring 124 is located on the outer peripheral side of the elastic membrane 123 and is disposed around the elastic membrane 123 to be fixed on the lower surface of the base 122. The retainer ring 124 serves to retain the wafer W under the elastic membrane 123 to prevent the wafer W from slipping out.

As shown in fig. 2, a main pressure chamber Z0 is formed between the upper structure 11, the lower structure 12 and the flexible connecting element 13, and the flexible connecting element 13 can be extended and contracted by controlling the pressure in the main pressure chamber Z0, so that the lower structure 12 can move up and down relative to the upper structure 11.

In the embodiment shown in FIG. 2, the upper pneumatic assembly 60 includes a first pneumatic circuit by which the main pressure chamber Z0 communicates with a gas source to independently control the pressure within the main pressure chamber Z0 to control the up and down movement of the substructure 12 as a whole. Wherein the gas source may include a positive pressure source and a negative pressure source, and the negative pressure source may be a vacuum source.

In addition, as shown in fig. 2, a predetermined number of concentric pressure chambers are provided inside the elastic membrane 123. Correspondingly, the upper pneumatic assembly 60 further includes the predetermined number of air passages to be connected in one-to-one correspondence with the concentric pressure chambers.

Taking the example of 3 pressure chambers provided in fig. 2 as an example, the pressure chambers provided in the elastic membrane 123 are a 1 st pressure chamber Z1, a 2 nd pressure chamber Z2, and a 3 rd pressure chamber Z3, which are concentrically provided in this order from the center to the outside. The 1 st pressure chamber Z1 located at the center is circular, and the 2 nd pressure chamber Z2 and the 3 rd pressure chamber Z3 are concentric annular. It is understood that the number of pressure chambers shown in fig. 2 is only an example, and other numbers are possible, for example, the number of pressure chambers may be 4, 5, 6, 7, etc.

In the embodiment shown in FIG. 2, the upper pneumatic assembly 60 further includes a second pneumatic circuit, a third pneumatic circuit, and a fourth pneumatic circuit. The 1 st pressure chamber Z1, the 2 nd pressure chamber Z2 and the 3 rd pressure chamber Z3 are respectively communicated with an air source through a second air path, a third air path and a fourth air path so as to respectively and independently control the pressure in different pressure chambers. Each pressure chamber may apply a different pressure to its respective zone of the wafer.

As shown in fig. 3(a) to 3(c), the suction process of the carrier head 10 for sucking the wafer W mainly includes:

step 1, as shown in fig. 3(a), a negative pressure is applied to the main pressure chamber Z0 of the carrier head 10 to move the lower structure 12 upward, the carrier head 10 is lifted up, so that a space with a certain distance in the vertical direction is formed between the carrier head 10 and the handling section, and the wafer W is held by a robot (not shown) and moved to the handling section through the space;

step 2, as shown in fig. 3(b), the carrier head 10 is kept raised, and the wafer W is placed at the central position of the loading/unloading part to align the carrier head 10;

step 3, as shown in fig. 3(c), the main pressure chamber Z0 of the carrier head 10 is vented to atmosphere to move the lower structure 12 downward, and the carrier head 10 is in a falling state, so that the carrier head 10 can adsorb the wafer W to carry the wafer W to perform a subsequent polishing process.

It can be understood that, since the carrier head 10 needs to introduce gas with a preset pressure into each pressure chamber after completing the wafer suction process to press the wafer W against the polishing pad to perform the polishing process, in order to accurately measure the pressure during the polishing process, zero calibration needs to be performed on the pressure sensor during the wafer suction process of each wafer W to overcome the zero offset problem of the pressure sensor. That is, the carrier head 10 performs a new zero calibration of the pressure sensor each time a pick-up process is performed.

Specifically, the pressure sensor calibration zero point is completed in the process of executing the 2 nd step to the 3 rd step. However, in the process of performing the steps 2 to 3, the pressure in the main pressure chamber Z0 of the carrier head 10 is changed from negative pressure to positive pressure, the response time is too long, it is difficult to determine the timing of zero point calibration, i.e., the timing when the pressure in the main pressure chamber Z0 is atmospheric pressure, and therefore, the zero point offset value of the real pressure sensor cannot be obtained.

The zero offset value refers to a value that the pressure sensor should output when the pressure sensor is open to the atmosphere is 0, but the actual output value is not 0, and the actual output value is regarded as the zero offset value, that is, the measurement error of the pressure sensor. After the measurement error is acquired, the measurement error is subtracted from the pressure value output by the pressure sensor, and then the real pressure can be obtained. Therefore, the accuracy of the acquired zero offset value is critical to the accuracy of the pressure sensor measurement. The accurate zero offset value can be obtained only when the pressure sensor is communicated with the atmosphere, but in the process of sucking the sheet, because the air pressure in the main pressure chamber Z0 is constantly changed, it is not accurately known when the air pressure in the main pressure chamber Z0 is the atmospheric pressure, and it is also not possible to determine when to collect the zero offset value of the pressure sensor communicated with the main pressure chamber Z0.

Also, it takes a long time to zero-point calibrate the pressure sensor using the pressure in the main pressure chamber Z0, for example, if the zero-point calibration is performed at a set interval of 500ms in the prior art, the total time for completing the zero-point calibration is at least more than 500 ms.

In order to solve the above problems and improve the accuracy and rapidity of zero calibration of the pressure sensor, the present application provides a wafer carrier 70 for chemical mechanical polishing. The wafer carrier 70 includes a carrier head 10 and an upper pneumatic assembly 60.

As shown in fig. 4, the upper pneumatic assembly 60 includes a first air passage connected between the air source and the main pressure chamber Z0, a pressure sensor 65 and a first solenoid valve 66 connected to a branch of the first air passage, the pressure sensor 65 is used for detecting the pressure value in the main pressure chamber Z0, and the pressure sensor 65 is directly connected to an air passage port of the main pressure chamber Z0 through the first solenoid valve 66 so as to communicate the branch with the atmosphere when the pressure sensor 65 is calibrated to the zero point without changing the pressure in the main pressure chamber Z0.

In addition, the upper pneumatic assembly 60 is connected to the controller.

During the wafer suction process of the carrier head 10, in the process of changing the pressure in the main pressure chamber Z0 from negative pressure to positive pressure, the controller controls the first solenoid valve 66 to be energized so as to make the pressure sensor 65 communicate with the atmosphere quickly, thereby shortening the time for the pressure sensor 65 to check the zero point.

In this embodiment, when the pressure sensor 65 corrects the zero point, the first solenoid valve 66 is controlled to communicate with the atmosphere to accurately obtain the zero point offset value of the pressure sensor 65 when the atmospheric pressure is measured, so that the pressure value detected by the pressure sensor 65 is corrected by using the zero point offset value in the pressure control software to obtain the accurate real pressure in the pressure chamber, thereby improving the accuracy of pressure control. And, the controller can control the first solenoid valve 66 to be turned on rapidly, thereby implementing the zero point calibration of the pressure sensor 65 in a short time. Actual tests show that zero point calibration can be completed only in 200ms to 300ms, and it can be seen that after the embodiment is adopted, the zero point calibration time of the pressure sensor 65 is reduced by at least 40%, so that the speed of processing the wafer by the carrier head 10 is increased by about 5%, and further the productivity (WPH, wafer per hour) of the chemical mechanical polishing equipment is increased from 45 to 50 to 47 to 53.

In this embodiment, by controlling the on-off of the first electromagnetic valve 66, the pressure sensor 65 is rapidly switched between two states of pressure detection in the main pressure chamber Z0 and atmospheric venting, so that on one hand, the problem that the pressure sensor 65 connected to the main pressure chamber Z0 is inaccurate when checking the zero point in the wafer suction process can be solved, on the other hand, the time consumed for checking the zero point can be shortened, and the pressure sensor checking process can be rapidly completed, thereby improving the productivity (WPH, wafer per hour) of the chemical mechanical polishing apparatus.

In another embodiment, the upper pneumatic assembly 60 is connected to a controller, and the controller receives the auto-zero command and then controls the first solenoid valve 66 to be energized to open the pressure sensor 65 to the atmosphere so as to obtain an accurate zero offset value of the pressure sensor 65.

As shown in fig. 4, the first solenoid valve 66 is a two-position three-way solenoid valve, a normally open port of the first solenoid valve 66 is directly communicated with the air passage port of the main pressure chamber Z0, a normally open port of the first solenoid valve 66 is communicated with the atmosphere, and a common port of the first solenoid valve 66 is connected to the pressure sensor 65.

The normally open port of the solenoid valve referred to herein means a port that is communicated with the common port when the solenoid valve is de-energized and is not communicated with the common port when the solenoid valve is energized, and the normally open port means a port that is not communicated with the common port when the solenoid valve is de-energized and is communicated with the common port when the solenoid valve is energized.

The characteristic parameters of the first solenoid valve 66 are as follows: wherein the flow rate of the gas passing through the reactor is 20-25L/min, preferably 22L/min; the on-off response time is 20-30ms, preferably 25 ms; the size of the valve body is 39mm multiplied by 27mm multiplied by 15.5 mm. Specifically, a two-position three-way solenoid valve with the model number of 6106 and 147994-3_2-way can be selected. In order to shorten the length of the gas pipeline between the normally-open port of the first electromagnetic valve 66 and the detection port of the pressure sensor as much as possible, the electromagnetic valve with a small size needs to be selected, so that the flow of gas passing through the electromagnetic valve is low, but the on-off time is also shortened, and the requirement that the pressure sensor 65 is rapidly communicated with the atmosphere can be met under the balance of the two.

The length of a gas pipeline between the normally-off port of the first electromagnetic valve 66 and the detection port of the pressure sensor is 55-60mm, preferably 57mm, so that the pipeline for opening the atmosphere is shortened as much as possible under the condition that the size of the valve body is limited, and the rapid atmosphere opening is realized; the volume of the gas line is 1-1.5ml, preferably 1.1 ml.

As shown in fig. 4, the first air circuit includes a switch control module, two input ends of the switch control module are respectively connected with a positive pressure source and a negative pressure source, and an output end of the switch control module is connected with the main pressure chamber Z0.

As shown in fig. 4, the switching control module includes a proportional solenoid valve 61 for controlling the magnitude of the gas pressure, a second solenoid valve 62 for positive-negative pressure switching, a third solenoid valve 63 for venting to atmosphere, and a fourth solenoid valve 64 for holding pressure.

The second solenoid valve 62, the third solenoid valve 63 and the fourth solenoid valve 64 are two-position three-way solenoid valves.

The characteristic parameters of the second solenoid valve 62, the third solenoid valve 63 and the fourth solenoid valve 64 are: wherein the flow rate of the gas passing through the reactor is 130-135L/min, preferably 132L/min; the on-off response time is less than 30 ms; the size of the valve body is 45mm multiplied by 89.4 mm. Specifically, a two-position three-way electromagnetic valve with the model number of VO317V-5G can be selected.

The first port of the electromagnetic proportional valve 61 is connected with a positive pressure source, the second port of the electromagnetic proportional valve 61 is connected with a normally-off port of the second electromagnetic valve 62, a normally-on port of the second electromagnetic valve 62 is connected with a negative pressure source, a common port of the second electromagnetic valve 62 is connected with a normally-off port of the third electromagnetic valve 63, the normally-on port of the third electromagnetic valve 63 is communicated with the atmosphere, the common port of the third electromagnetic valve 63 is connected with a normally-on port of the fourth electromagnetic valve 64, the normally-off port of the fourth electromagnetic valve 64 is communicated with the atmosphere, and the common port of the fourth electromagnetic valve 64 is communicated with an air path port of the main pressure chamber Z0.

The upper pneumatic assembly 60 shown in fig. 4, connected to the main pressure chamber Z0, has mainly 5 operating states, respectively: positive pressure output, negative pressure output, atmosphere ventilation, pressure maintaining and zero point calibration. In these 5 operating states, the operation of each valve is shown in table 1.

TABLE 1 flow of operation of the upper pneumatic assembly connected to the main pressure chamber

Electromagnetic proportional valve

Second electromagnetic valve

Third solenoid valve

Fourth solenoid valve

Pressure sensor

First electromagnetic valve

Positive pressure output

TRUE

FALSE

TRUE

FALSE

Negative pressure output

Has no influence on

FALSE

TRUE

FALSE

TRUE

FALSE

Is communicated with the atmosphere

Has no influence on

FALSE

TRUE

FALSE

Pressure maintaining device

Has no influence on

TRUE

FALSE

Zero point of calibration

Has no influence on

FALSE

TRUE

In table 1, TRUE indicates that the device is powered on, FALSE indicates that the device is powered off, and no effect indicates that power is on or off.

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 respective portions and their mutual relationships. 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 show the structure of the 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 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 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 wafer carrier device for chemical mechanical polishing is characterized by comprising a carrier head and an upper pneumatic assembly;

2. The wafer carrying device according to claim 1, wherein the first solenoid valve is a two-position three-way solenoid valve, a normally-open port of the first solenoid valve is directly communicated with a gas path port of the main pressure chamber, a normally-open port of the first solenoid valve is communicated with the atmosphere, and a common port of the first solenoid valve is connected to the pressure sensor.

3. The wafer carrier device according to claim 1, wherein the first air path comprises a switch control module, two input ends of the switch control module are connected to a positive pressure source and a negative pressure source, and an output end of the switch control module is connected to the main pressure chamber.

4. The wafer carrier device according to claim 3, wherein the switch control module comprises a proportional solenoid valve for controlling the magnitude of the gas pressure, a second solenoid valve for positive and negative pressure switching, a third solenoid valve for venting to atmosphere, and a fourth solenoid valve for holding pressure.

5. The wafer carrier device of claim 4, wherein the second solenoid valve, the third solenoid valve, and the fourth solenoid valve are two-position three-way solenoid valves.

6. The wafer carrying device according to claim 5, wherein the first port of the electromagnetic proportional valve is connected to a positive pressure source, the second port of the electromagnetic proportional valve is connected to a normally-open port of the second electromagnetic valve, the normally-open port of the second electromagnetic valve is connected to a negative pressure source, the common port of the second electromagnetic valve is connected to a normally-open port of the third electromagnetic valve, the normally-open port of the third electromagnetic valve is communicated with the atmosphere, the common port of the third electromagnetic valve is connected to a normally-open port of the fourth electromagnetic valve, the normally-open port of the fourth electromagnetic valve is communicated with the atmosphere, and the common port of the fourth electromagnetic valve is communicated with the gas path port of the main pressure chamber.

7. The wafer carrier device of claim 1, wherein the lower structure comprises a gimbal, a base, a flexible membrane, and a retaining ring; the balancing stand is slidably arranged in the central through hole of the upper structure and can drive the base to move up and down, the elastic membrane is arranged on the bottom surface of the base, and the outer peripheral side of the elastic membrane is provided with a retaining ring connected with the bottom surface of the base.

8. The wafer carrier device of claim 7, wherein a predetermined number of concentric pressure chambers are disposed within the membrane, and wherein the upper pneumatic assembly further comprises the predetermined number of pneumatic circuits in one-to-one correspondence with the concentric pressure chambers.

9. A chemical mechanical polishing apparatus, comprising:

the wafer carrier of any of claims 1-8;

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