Method and system for testing electrostatic force of electrostatic chuck

Abstract

The invention provides a method and system for testing the electrostatic force of an electrostatic chuck, and the method is applied to a data processing module in the system for testing the electrostatic force of the electrostatic chuck. The system also comprises a to-be-tested electrostatic chuck, a wafer, a pressure sensor, a laser transmitting module and a laser receiving module. The method comprises the following steps: controlling the gas pressure in a gas pipeline to be gradually increased so as to gradually increase the jacking force applied to an adsorbed wafer; the laser reflection condition is monitored through a laser emission module, and when the laser emission module monitors that a laser reflection path deviates, the pressure value of the gas pressure in the gas pipeline detected by a pressure sensor at the moment when the laser reflection path deviates is determined; calculating effective electrostatic force of the electrostatic chuck according to the pressure value; the effective electrostatic force is used for representing the maximum adsorption force of the electrostatic chuck to the wafer. By means of the method, high-precision, high-sensitivity, stable and reliable testing of the electrostatic force of the electrostatic chuck is achieved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a method and system for testing the electrostatic force of an electrostatic chuck. Background Art

[0002] Electrostatic chuck (E-Chuck) is a device that uses the principle of electrostatic adsorption to fix the workpiece. In the field of semiconductor manufacturing, electrostatic chuck uses electrostatic force (especially Coulomb force) to generate adsorption force to fix the wafer. Accurately testing the electrostatic force (adsorption force) of electrostatic chuck is a key step in optimizing the design and performance of electrostatic chuck.

[0003] At present, the commonly used electrostatic force test method is the lifting method, but this method has many disadvantages. During the operation of the lifting method, it is difficult to accurately control the parameters such as the force and speed of the lifting, which is easy to introduce human operation errors, resulting in large deviations in the test results and low test accuracy. Secondly, the lifting process is significantly affected by external environmental factors (such as vibration, airflow disturbance, etc.). Moreover, each time a test is performed, the lifting device and the wafer need to be fixed, and the fixing process is complicated and cumbersome. Therefore, the repeatability of the lifting method test is poor. Furthermore, the lifting method has poor sensitivity when testing tiny electrostatic forces, and it is difficult to accurately reflect the subtle changes in the electrostatic force of the electrostatic chuck, which limits more in-depth and detailed research and improvement on the performance of the electrostatic chuck. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide a method and system for testing the electrostatic force of an electrostatic chuck, so as to solve the problems of low precision, susceptibility to interference, poor sensitivity, etc. in the existing pulling method for testing the electrostatic force of an electrostatic chuck, and to achieve high-precision, high-sensitivity, stable and reliable testing of the electrostatic force of the electrostatic chuck.

[0005] In a first aspect, an embodiment of the present application provides a method for testing the electrostatic force of an electrostatic chuck, the method being applied to a data processing module in a testing system for the electrostatic force of an electrostatic chuck; the system further comprises: an electrostatic chuck to be tested, a wafer, a pressure sensor, a laser emitting module and a laser receiving module; wherein the wafer is arranged on the electrostatic chuck, and the electrostatic chuck uses electrostatic force to generate an adsorption force to fix the wafer; the laser emitting module and the laser receiving module are arranged above the upper surface of the wafer, the laser emitting module is used to emit a laser to a point to be detected on the upper surface of the wafer, so that the reflected light of the laser is received by the laser receiving module; the electrostatic chuck contains a gas pipeline inside, the gas pipeline is evenly distributed on the lower surface of the wafer, and the gas pressure in the gas pipeline acts evenly on the lower surface of the wafer; the gas pressure in the gas pipeline is used to generate an upward thrust force on the adsorbed wafer; the pressure sensor is used to detect the gas pressure in the gas pipeline; the method comprises: Step S1: controlling the gas pressure in the gas pipeline to gradually increase so that the pushing force exerted on the adsorbed wafer gradually increases; Step S2: monitoring the laser reflection condition by the laser emission module, and when the laser emission module detects that the laser reflection route is offset, determining the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor at the moment when the laser reflection route is offset; Step S3: calculating the effective electrostatic force of the electrostatic chuck according to the pressure value; the effective electrostatic force is used to characterize the maximum adsorption force of the electrostatic chuck on the wafer.

[0006] In combination with the first aspect, the embodiment of the present application provides a first possible implementation of the first aspect, wherein the system further includes a pressure regulating module, the pressure regulating module is connected to the gas inlet of the gas pipeline; and the step of controlling the gas pressure in the gas pipeline to gradually increase includes: A gas pressure adjustment instruction is sent to the pressure adjustment module, so that the pressure adjustment module gradually increases the gas pressure in the gas pipeline according to the gas pressure adjustment step included in the gas pressure adjustment instruction.

[0007] In combination with the first aspect, the embodiment of the present application provides a second possible implementation of the first aspect, wherein the calculating the effective electrostatic force of the electrostatic chuck according to the pressure value includes: Repeating the replacement of the wafer on the electrostatic chuck, and repeating steps S1 to S2 for each new wafer replaced, to obtain a pressure value corresponding to each wafer; Calculate the average of all the pressure values ​​to obtain an average pressure value; The effective electrostatic force of the electrostatic chuck is calculated according to the average pressure value. In combination with the second possible implementation of the first aspect, the embodiment of the present application provides a third possible implementation of the first aspect, wherein the calculating the effective electrostatic force of the electrostatic chuck according to the average pressure value includes: The effective electrostatic force of the electrostatic chuck is calculated by the following formula:

[0008] Wherein, F represents the effective electrostatic force; S1 represents the contact area between the wafer and the electrostatic chuck; S2 represents the contact area between the gas and the wafer; Indicates the average pressure value.

[0009] In combination with the first aspect, an embodiment of the present application provides a fourth possible implementation of the first aspect, wherein the system also includes a bracket, the bracket including support legs and a disc, the support legs are located on the base of the electrostatic chuck, the support legs are used to support the disc so that the disc is located directly above the wafer on the electrostatic chuck and at a preset distance from the wafer; the laser emitting module and the laser receiving module are installed on the disc.

[0010] In combination with the fourth possible implementation of the first aspect, an embodiment of the present application provides a fifth possible implementation of the first aspect, wherein a first number of first slides are arranged at the edge of the disc, and the first number is the same as the number of the supporting legs; each of the supporting legs corresponds to one first slide, and the distribution of the supporting legs on the base is the same as the distribution of the first slides on the disc; for each of the supporting legs, an end of the supporting leg away from the base is arranged in the first slide corresponding to the supporting leg, so that the disc can rotate based on the first slide corresponding to each of the supporting legs.

[0011] In combination with the fourth possible implementation of the first aspect, the embodiment of the present application provides a sixth possible implementation of the first aspect, wherein the center of the disk is arranged to be a cross-shaped hollow skeleton; there is at least one group of the laser emitting module and the laser receiving module, and each group of the laser emitting module and the laser receiving module is symmetrically and slidably arranged on the cross-shaped hollow skeleton.

[0012] In combination with the fourth possible implementation of the first aspect, the embodiment of the present application provides a seventh possible implementation of the first aspect, wherein the gas pipeline includes a straight pipeline and a plurality of circular pipelines with different radii; wherein the position of the straight pipeline is the position of any diameter in the electrostatic chuck; the central projection of the plurality of circular pipelines with different radii is the same as the central projection of the electrostatic chuck; the plurality of circular pipelines with different radii are arranged at equal intervals on the lower surface of the disc so that the circular pipelines are evenly distributed on the lower surface of the disc; each of the circular pipelines is connected to the straight pipeline, and the straight pipelines are also respectively connected to the pressure sensor and the air inlet of the gas pipeline.

[0013] In combination with the first aspect, an embodiment of the present application provides an eighth possible implementation of the first aspect, wherein the wafer is a silicon wafer.

[0014] In a second aspect, an embodiment of the present application further provides a test system for the electrostatic force of an electrostatic chuck, the system comprising: a data processing module, an electrostatic chuck to be tested, a wafer, a pressure sensor, a laser emitting module and a laser receiving module; wherein the wafer is arranged on the electrostatic chuck, and the electrostatic chuck uses electrostatic force to generate adsorption force to fix the wafer; the laser emitting module and the laser receiving module are arranged above the upper surface of the wafer, and the laser emitting module is used to emit a laser to a point to be detected on the upper surface of the wafer, so that the reflected light of the laser is received by the laser receiving module; the electrostatic chuck contains a gas pipeline inside, and the gas pipeline is evenly distributed on the lower surface of the wafer, and the gas pressure in the gas pipeline acts evenly on the lower surface of the wafer; the gas pressure in the gas pipeline is used to generate an upward thrust force on the adsorbed wafer; the pressure sensor is used to detect the gas pressure in the gas pipeline; the data processing module is used to execute: Step S1: controlling the gas pressure in the gas pipeline to gradually increase so that the pushing force exerted on the adsorbed wafer gradually increases; Step S2: monitoring the laser reflection condition by the laser emission module, and when the laser emission module detects that the laser reflection route is offset, determining the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor at the moment when the laser reflection route is offset; Step S3: calculating the effective electrostatic force of the electrostatic chuck according to the pressure value; the effective electrostatic force is used to characterize the maximum adsorption force of the electrostatic chuck on the wafer.

[0015] The present application provides a method and system for testing the electrostatic force of an electrostatic chuck. In this embodiment, the deformation of the wafer is monitored by the principle of laser reflection, and the deformation of the wafer caused by subtle changes in the electrostatic force can be captured, thereby accurately reflecting the changes in the adsorption performance of the electrostatic chuck. In addition, the test process is based on a closed and stable gas pressurization and laser optical monitoring system. The internal test environment is minimally disturbed by external vibrations and airflow. The pressure sensor works in coordination with the laser transmitting module and the laser receiving module with high stability, ensuring the repeatability and accuracy of the test results, and providing a stable test environment for the stable performance evaluation of the electrostatic chuck.

[0016] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A side view of a system for testing the electrostatic force of an electrostatic chuck provided in an embodiment of the present application is shown; Figure 2 A flow chart showing a method for testing the electrostatic force of an electrostatic chuck provided in an embodiment of the present application is shown; Figure 3 A three-dimensional schematic diagram of a system for testing the electrostatic force of an electrostatic chuck provided in an embodiment of the present application is shown; Figure 4 A schematic diagram of the layout of a gas pipeline provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0019] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0020] Considering the problems of low precision, susceptibility to interference, poor sensitivity, etc. when using the Czochralski method to test the electrostatic force of an electrostatic chuck, the present invention provides a method and system for testing the electrostatic force of an electrostatic chuck to achieve high-precision, high-sensitivity, stable and reliable testing of the electrostatic force of an electrostatic chuck, which is described below through an embodiment.

[0021] To facilitate understanding of this embodiment, a method for testing the electrostatic force of an electrostatic chuck disclosed in an embodiment of the present application is first described in detail. The method is applied to a data processing module in a system for testing the electrostatic force of an electrostatic chuck; Figure 1 As shown, the system also includes: an electrostatic chuck to be tested, a wafer, a pressure sensor, a laser emitting module and a laser receiving module; wherein the wafer is arranged on the electrostatic chuck, and the electrostatic chuck uses electrostatic force to generate adsorption force to fix the wafer; a laser emitting module and a laser receiving module are arranged above the upper surface of the wafer, and the laser emitting module is used to emit laser to the point to be tested on the upper surface of the wafer, so that the reflected light of the laser is received by the laser receiving module; the electrostatic chuck contains a gas pipeline, and the gas pipeline is evenly distributed on the lower surface of the wafer, and the gas pressure in the gas pipeline acts evenly on the lower surface of the wafer; the gas pressure in the gas pipeline is used to generate an upward thrust on the adsorbed wafer; the pressure sensor is used to detect the gas pressure in the gas pipeline.

[0022] like Figure 2 As shown, the method comprises the following steps S1-S3: Step S1: Controlling the gas pressure in the gas pipeline to gradually increase so that the pushing force on the adsorbed wafer gradually increases; Step S2: monitoring the laser reflection condition through the laser emission module, and when the laser emission module detects that the laser reflection route is offset, determining the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor at the moment when the laser reflection route is offset; Step S3: Calculate the effective electrostatic force of the electrostatic chuck according to the pressure value; the effective electrostatic force is used to characterize the maximum adsorption force of the electrostatic chuck on the wafer.

[0023] In step S1, the wafer is simultaneously subjected to the downward adsorption force generated by the electrostatic chuck on the wafer using electrostatic force, and the upward thrust force exerted on the wafer by the gas in the gas pipeline. The upward thrust force exerted on the wafer by the gas in the gas pipeline is the same as the gas pressure in the gas pipeline. In this embodiment, the limit value of the downward adsorption force generated by the electrostatic chuck on the wafer using electrostatic force is tested by gradually increasing the gas pressure in the gas pipeline, that is, gradually increasing the upward thrust force exerted on the wafer.

[0024] In this embodiment, the gas filled into the gas pipeline is an inert gas.

[0025] In step S2, it is considered that when the upward thrust exerted by the gas in the gas pipeline on the wafer reaches the limit value of the downward adsorption force exerted by the electrostatic chuck on the wafer using the electrostatic force, the wafer will be deformed. Based on this, in this embodiment, the laser reflection situation is monitored in real time by the laser emission module. When the laser emission module detects that the laser reflection path is offset, it means that the wafer has been deformed due to the upward thrust exerted by the gas in the gas pipeline. At this time, the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor at this moment (that is, the moment when the laser reflection path is offset, that is, the moment when the wafer is deformed) is recorded. In this embodiment, if Figure 1 As shown, the gas pipeline is connected to the pressure sensor, so that the pressure sensor can detect the gas pressure in the gas pipeline in real time.

[0026] In step S3, the effective electrostatic force of the electrostatic chuck can be calculated based on the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor when the laser reflection path is offset, wherein the effective electrostatic force is used to characterize the maximum adsorption force of the electrostatic chuck on the wafer.

[0027] In a possible implementation, Figure 3 As shown, the system also includes a bracket, which includes supporting legs and a disc. The supporting legs are located on the base of the electrostatic chuck, and the supporting legs are used to support the disc so that the disc is located directly above the wafer on the electrostatic chuck and at a preset distance from the wafer; the laser emitting module and the laser receiving module are installed on the disc.

[0028] A first number of first slides are arranged at the edge of the disc, and the first number is the same as the number of supporting legs; each supporting leg corresponds to a first slide, and the distribution of the supporting legs on the base is the same as the distribution of the first slides on the disc; for each supporting leg, an end of the supporting leg away from the base is arranged in the first slide corresponding to the supporting leg, so that the disc can rotate based on the first slides corresponding to each supporting leg.

[0029] In this embodiment, if Figure 3 As shown, the first number is 2, that is, there are two support legs, which are symmetrically arranged at the edge of the base to support the disc. There are also two first slideways. After the support legs are installed on the first slideway, the disc can rotate based on the first slideway.

[0030] In a possible implementation, Figure 3 As shown, the center of the disk is set to a cross-shaped hollow frame; there is at least one group of laser emitting modules and laser receiving modules, and each group of laser emitting modules and laser receiving modules is symmetrically and slidably arranged on the cross-shaped hollow frame.

[0031] In this embodiment, Figure 3 Only one set of laser emitting modules and laser receiving modules is shown. In actual application, multiple sets of laser emitting modules and laser receiving modules can be set on the M-shaped hollow skeleton. The laser emitting modules and laser receiving modules in the same set are symmetrically arranged. Different sets of laser emitting modules and laser receiving modules are used to detect different points to be detected on the upper surface of the wafer.

[0032] It can be seen that in this embodiment, multiple groups of laser emitting modules and laser receiving modules can be flexibly arranged above different points of the wafer as needed, and multi-position monitoring can be carried out simultaneously to obtain deformation data of multiple points at one time, thereby achieving a comprehensive analysis of the differences in electrostatic force distribution in different areas of the electrostatic chuck, and helping to optimize the structural design of the electrostatic chuck and the electrostatic distribution control.

[0033] In a possible implementation, the system further includes a pressure regulating module, and the pressure regulating module is connected to the gas inlet of the gas pipeline; when executing step S1, the following steps may be specifically performed: A gas pressure adjustment instruction is sent to the pressure adjustment module, so that the pressure adjustment module gradually increases the gas pressure in the gas pipeline according to the gas pressure adjustment step length included in the gas pressure adjustment instruction.

[0034] In this embodiment, the gas inlet is located at the bottom center of the base of the electrostatic chuck. The pressure regulating module can gradually deliver gas to the gas pipeline according to the step size included in the gas pressure regulation instruction to gradually increase the gas pressure in the gas pipeline. Exemplarily, the step size can be 0.01 MPa.

[0035] In a possible implementation manner, when executing step S3, the following steps S301-S303 may be specifically performed: S301: Repeatedly replace the wafer on the electrostatic chuck, and for each new wafer replaced, repeat steps S1 to S2 to obtain the pressure value corresponding to each wafer; S302: Calculate the average of all pressure values ​​to obtain an average pressure value; S303: Calculate the effective electrostatic force of the electrostatic chuck according to the average pressure value.

[0036] In this embodiment, the test is repeated 5 to 10 times, and the system device is reset at the end of each test. The average pressure value is substituted into the calculation formula to calculate the effective electrostatic force.

[0037] In one possible implementation, the effective electrostatic force of the electrostatic chuck can be calculated by the following formula:

[0038] Where, F represents the effective electrostatic force; S1 represents the contact area between the wafer and the electrostatic chuck; S2 represents the contact area between the gas and the wafer; Indicates the average pressure value.

[0039] In a possible implementation, Figure 4 As shown, the gas pipeline includes a straight pipeline and multiple circular pipelines with different radii; wherein, the position of the straight pipeline is the position of any diameter in the electrostatic chuck; the central projection of the multiple circular pipelines with different radii is the same as the central projection of the electrostatic chuck; the multiple circular pipelines with different radii are arranged at equal intervals on the lower surface of the disk so that the circular pipelines are evenly distributed on the lower surface of the disk; each circular pipeline is connected to the straight pipeline, and the straight pipeline is also connected to the pressure sensor and the air inlet respectively.

[0040] In a possible implementation manner, the wafer is a silicon wafer.

[0041] In this embodiment, the electrostatic force test system of the electrostatic chuck has a compact structure and conventional component selection, and does not require the assistance of complex large-scale equipment, thereby reducing equipment procurement and maintenance costs; the operating process is simple, the test parameters are easy to set and adjust, the single test time is short, and multiple repeated tests can be completed efficiently, which greatly shortens the electrostatic force test cycle in the research and development stage and accelerates the product iteration and optimization process.

[0042] Based on the same technical concept, the embodiment of the present application also provides a test system for the electrostatic force of an electrostatic chuck, the system comprising: a data processing module, an electrostatic chuck to be tested, a wafer, a pressure sensor, a laser emitting module and a laser receiving module; wherein the wafer is arranged on the electrostatic chuck, and the electrostatic chuck uses electrostatic force to generate adsorption force to fix the wafer; the laser emitting module and the laser receiving module are arranged above the upper surface of the wafer, and the laser emitting module is used to emit laser to the point to be detected on the upper surface of the wafer, so that the reflected light of the laser is received by the laser receiving module; the electrostatic chuck contains a gas pipeline inside, and the gas pipeline is evenly distributed on the lower surface of the wafer, and the gas pressure in the gas pipeline acts evenly on the lower surface of the wafer; the gas pressure in the gas pipeline is used to generate an upward thrust force on the adsorbed wafer; the pressure sensor is used to detect the gas pressure in the gas pipeline; the data processing module is used to execute: Step S1: controlling the gas pressure in the gas pipeline to gradually increase so that the pushing force exerted on the adsorbed wafer gradually increases; Step S2: monitoring the laser reflection condition by the laser emission module, and when the laser emission module detects that the laser reflection route is offset, determining the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor at the moment when the laser reflection route is offset; Step S3: calculating the effective electrostatic force of the electrostatic chuck according to the pressure value; the effective electrostatic force is used to characterize the maximum adsorption force of the electrostatic chuck on the wafer.

[0043] Optionally, the system further comprises a pressure regulating module, wherein the pressure regulating module is connected to the gas inlet of the gas pipeline; when the data processing module is used to perform step S1, it is specifically used to: A gas pressure adjustment instruction is sent to the pressure adjustment module, so that the pressure adjustment module gradually increases the gas pressure in the gas pipeline according to the gas pressure adjustment step included in the gas pressure adjustment instruction.

[0044] Optionally, when the data processing module is used to execute step S3, it is specifically used to: Repeating the replacement of the wafer on the electrostatic chuck, and repeating steps S1 to S2 for each new wafer replaced, to obtain a pressure value corresponding to each wafer; Calculate the average of all the pressure values ​​to obtain an average pressure value; The effective electrostatic force of the electrostatic chuck is calculated according to the average pressure value.

[0045] Optionally, when the data processing module is used to execute the step of calculating the effective electrostatic force of the electrostatic chuck according to the average pressure value, it is specifically used to: The effective electrostatic force of the electrostatic chuck is calculated by the following formula:

[0046] Wherein, F represents the effective electrostatic force; S1 represents the contact area between the wafer and the electrostatic chuck; S2 represents the contact area between the gas and the wafer; Indicates the average pressure value.

[0047] Optionally, the system also includes a bracket, which includes supporting legs and a disc, the supporting legs are located on the base of the electrostatic chuck, and the supporting legs are used to support the disc so that the disc is located directly above the wafer on the electrostatic chuck and at a preset distance from the wafer; the laser emitting module and the laser receiving module are installed on the disc.

[0048] Optionally, a first number of first slides are arranged at the edge of the disc, and the first number is the same as the number of the supporting legs; each supporting leg corresponds to one first slide, and the distribution of the supporting legs on the base is the same as the distribution of the first slides on the disc; for each supporting leg, an end of the supporting leg away from the base is arranged in the first slide corresponding to the supporting leg, so that the disc can rotate based on the first slide corresponding to each supporting leg.

[0049] Optionally, the center of the disc is configured to be a cross-shaped hollow skeleton; there is at least one group of the laser emitting module and the laser receiving module, and each group of the laser emitting module and the laser receiving module is symmetrically and slidably configured on the cross-shaped hollow skeleton.

[0050] Optionally, the gas pipeline includes a straight pipeline and multiple circular pipelines with different radii; wherein the position of the straight pipeline is the position of any diameter in the electrostatic chuck; the central projection of the multiple circular pipelines with different radii is the same as the central projection of the electrostatic chuck; the multiple circular pipelines with different radii are arranged at equal intervals on the lower surface of the disc so that the circular pipelines are evenly distributed on the lower surface of the disc; each of the circular pipelines is connected to the straight pipeline, and the straight pipelines are also respectively connected to the pressure sensor and the air inlet of the gas pipeline.

[0051] Optionally, the wafer is a silicon wafer.

[0052] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0053] In the several embodiments provided in the present application, it should be understood that the disclosed systems and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0054] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0055] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0056] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, and other media that can store program codes.

[0057] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for testing the electrostatic force of an electrostatic chuck, characterized in that: The method is applied to a data processing module in a test system of an electrostatic force of an electrostatic chuck; the system also includes: an electrostatic chuck to be tested, a wafer, a pressure sensor, a laser emitting module and a laser receiving module; wherein the wafer is arranged on the electrostatic chuck, and the electrostatic chuck uses electrostatic force to generate an adsorption force to fix the wafer; the laser emitting module and the laser receiving module are arranged above the upper surface of the wafer, and the laser emitting module is used to emit a laser to a point to be detected on the upper surface of the wafer, so that the reflected light of the laser is received by the laser receiving module; the electrostatic chuck contains a gas pipeline inside, and the gas pipeline is evenly distributed on the lower surface of the wafer, and the gas pressure in the gas pipeline evenly acts on the lower surface of the wafer; the gas pressure in the gas pipeline is used to generate an upward thrust force on the adsorbed wafer; the pressure sensor is used to detect the gas pressure in the gas pipeline; the method includes: Step S1: controlling the gas pressure in the gas pipeline to gradually increase so that the pushing force exerted on the adsorbed wafer gradually increases; Step S2: monitoring the laser reflection condition by the laser emission module, and when the laser emission module detects that the laser reflection route is offset, determining the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor at the moment when the laser reflection route is offset; Step S3: calculating the effective electrostatic force of the electrostatic chuck according to the pressure value; the effective electrostatic force is used to characterize the maximum adsorption force of the electrostatic chuck on the wafer.

2. The method according to claim 1, characterized in that: The system further includes a pressure regulating module, which is connected to the gas inlet of the gas pipeline; and controlling the gas pressure in the gas pipeline to gradually increase includes: A gas pressure adjustment instruction is sent to the pressure adjustment module, so that the pressure adjustment module gradually increases the gas pressure in the gas pipeline according to the gas pressure adjustment step included in the gas pressure adjustment instruction.

3. The method according to claim 1, characterized in that: Calculating the effective electrostatic force of the electrostatic chuck according to the pressure value comprises: Repeating the replacement of the wafer on the electrostatic chuck, and for each new wafer replaced, repeating steps S1 to S2 to obtain the pressure value corresponding to each wafer; Calculate the average of all the pressure values ​​to obtain an average pressure value; The effective electrostatic force of the electrostatic chuck is calculated according to the average pressure value.

4. The method according to claim 3, characterized in that: Calculating the effective electrostatic force of the electrostatic chuck according to the average pressure value comprises: The effective electrostatic force of the electrostatic chuck is calculated by the following formula: Wherein, F represents the effective electrostatic force; S1 represents the contact area between the wafer and the electrostatic chuck; S2 represents the contact area between the gas and the wafer; Indicates the average pressure value.

5. The method according to claim 1, characterized in that: The system also includes a bracket, which includes supporting legs and a disc, wherein the supporting legs are located on the base of the electrostatic chuck, and the supporting legs are used to support the disc so that the disc is located directly above the wafer on the electrostatic chuck and is at a preset distance from the wafer; the laser emitting module and the laser receiving module are installed on the disc.

6. The method according to claim 5, characterized in that: A first number of first slides are arranged at the edge of the disc, and the first number is the same as the number of the supporting legs; each supporting leg corresponds to one first slide, and the distribution of the supporting legs on the base is the same as the distribution of the first slides on the disc; for each supporting leg, an end of the supporting leg away from the base is arranged in the first slide corresponding to the supporting leg, so that the disc can rotate based on the first slide corresponding to each supporting leg.

7. The method according to claim 5, characterized in that: The center of the disc is arranged to form a cross-shaped hollow frame; there is at least one group of the laser emitting module and the laser receiving module, and each group of the laser emitting module and the laser receiving module is symmetrically and slidably arranged on the cross-shaped hollow frame.

8. The method according to claim 5, characterized in that: The gas pipeline includes a straight pipeline and a plurality of circular pipelines with different radii; wherein the position of the straight pipeline is the position of any diameter in the electrostatic chuck; the central projection of the plurality of circular pipelines with different radii is the same as the central projection of the electrostatic chuck; the plurality of circular pipelines with different radii are arranged at equal intervals on the lower surface of the disk so that the circular pipelines are evenly distributed on the lower surface of the disk; each of the circular pipelines is connected to the straight pipeline, and the straight pipelines are also respectively connected to the pressure sensor and the air inlet of the gas pipeline.

9. The method according to claim 1, characterized in that: The wafer is a silicon wafer.

10. A system for testing the electrostatic force of an electrostatic chuck, characterized in that: The system comprises: a data processing module, an electrostatic chuck to be tested, a wafer, a pressure sensor, a laser emitting module and a laser receiving module; wherein the wafer is arranged on the electrostatic chuck, and the electrostatic chuck uses electrostatic force to generate adsorption force to fix the wafer; the laser emitting module and the laser receiving module are arranged above the upper surface of the wafer, and the laser emitting module is used to emit laser to the point to be detected on the upper surface of the wafer, so that the reflected light of the laser is received by the laser receiving module; the electrostatic chuck contains a gas pipeline inside, and the gas pipeline is evenly distributed on the lower surface of the wafer, and the gas pressure in the gas pipeline acts evenly on the lower surface of the wafer; the gas pressure in the gas pipeline is used to generate an upward thrust force on the adsorbed wafer; the pressure sensor is used to detect the gas pressure in the gas pipeline; the data processing module is used to execute: Step S1: controlling the gas pressure in the gas pipeline to gradually increase so that the pushing force exerted on the adsorbed wafer gradually increases; Step S2: monitoring the laser reflection condition by the laser emission module, and when the laser emission module detects that the laser reflection route is offset, determining the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor at the moment when the laser reflection route is offset; Step S3: calculating the effective electrostatic force of the electrostatic chuck according to the pressure value; the effective electrostatic force is used to characterize the maximum adsorption force of the electrostatic chuck on the wafer.

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