Method and system for testing electrostatic force of electrostatic chuck

Abstract

The invention provides a method and system for testing electrostatic force of an electrostatic chuck, the method is applied to a data processing module in the system for testing the electrostatic force of the electrostatic chuck, and the system further comprises a to-be-tested electrostatic chuck, a wafer for testing, a closed cavity, a pressure sensor, a gas pipeline and a gas leakage detector; the method comprises the following steps: controlling the gas pressure in a gas pipeline to be gradually increased so as to gradually increase the upward jacking force applied to an adsorbed wafer; detecting whether the gas in the gas pipeline leaks into the closed cavity or not through a gas leakage detector, and when the gas leakage detector detects that the gas in the gas pipeline leaks into the closed cavity, determining the pressure value of the gas pressure in the gas pipeline detected by a pressure sensor at the gas leakage moment; 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. Through the method, the test precision is improved.

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 pulling method, but this method has many disadvantages. During the operation of the pulling method, it is difficult to accurately control the pulling force, speed and other parameters, which can easily introduce human operation errors, resulting in large deviations in test results and low test accuracy. Secondly, the pulling process is significantly affected by external environmental factors (such as vibration, airflow disturbance, etc.). Moreover, each time a test is performed, the pulling device needs to be fixed to the wafer, and the fixing process is complicated and cumbersome. Therefore, the repeatability of the pulling method test is poor. 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 reduce human operating errors, improve test accuracy, avoid interference from the external environment, and improve the convenience of the test process.

[0005] In the 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 system for testing the electrostatic force of an electrostatic chuck, the system also comprising: an electrostatic chuck to be tested, a wafer for testing, a closed chamber, a pressure sensor, a gas pipeline, and a gas leakage detector; wherein the wafer is arranged on the electrostatic chuck, and the electrostatic chuck uses electrostatic force to generate a downward adsorption force to fix the wafer; the electrostatic chuck with the wafer fixed is arranged in the closed chamber, and the closed chamber is a vacuum chamber; the gas pipeline is arranged inside the electrostatic chuck, and some of the gas pipelines in the gas pipeline are evenly distributed in the The lower surface of the wafer is adhered to the part of the gas pipeline; the gas in the part of the gas pipeline directly contacts the lower surface of the wafer, so that the gas pressure in the gas pipeline generates an upward thrust on the adsorbed wafer; the pressure sensor is used to detect the gas pressure in the gas pipeline; the gas leakage detector is used to detect whether the gas in the gas pipeline leaks into the closed chamber. If the gas in the gas pipeline leaks into the closed chamber, it means that the wafer is subjected to an upward thrust exerted by the gas pressure in the gas pipeline, so that a gap appears between the wafer and the electrostatic chuck; the method comprises: Step S1: controlling the gas pressure in the gas pipeline to gradually increase so that the upward thrust force exerted on the adsorbed wafer gradually increases; Step S2: detecting whether the gas in the gas pipeline has leaked into the closed chamber by the gas leakage detector, and determining the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor at the time of gas leakage when the gas leakage detector detects that the gas in the gas pipeline has leaked into the closed chamber; 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 gas in the gas pipeline is helium.

[0007] In combination with the first aspect, the embodiment of the present application provides a second possible implementation of the first aspect, wherein the system further includes at least one gas extraction device, the gas extraction device is arranged at the edge of the contact surface between the wafer and the electrostatic chuck; the gas leakage detector is arranged outside the closed chamber; each of the gas extraction devices is connected to the gas leakage detector through its corresponding connecting pipe; the detecting whether the gas in the gas pipe leaks into the closed chamber by the gas leakage detector comprises: The gas near the edge of the contact surface is extracted by the gas extraction device, and the extracted gas is transported to the gas leakage detector through the connecting channel, so that the gas leakage detector can detect whether the gas in the gas pipeline leaks into the closed chamber.

[0008] 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, for each of the gas extraction devices, the gas extraction device includes a single-groove pipe, the groove opening of the single-groove pipe is arranged toward the edge of the contact surface, and the single-groove pipe and the edge of the contact surface constitute an independent space; each of the single-groove pipes is connected to the gas leakage detector through a corresponding connecting pipe; the gas near the edge of the contact surface is extracted by the gas extraction device, and the extracted gas is transported to the gas leakage detector through the connecting channel, including: The gas near the edge of the contact surface is extracted into the single groove pipe of the gas extraction device through the gas extraction device, and the gas extracted into the single groove pipe is transported to the gas leakage detector through the corresponding connecting channel.

[0009] In combination with the second possible implementation of the first aspect, the embodiment of the present application provides a fourth possible implementation of the first aspect, wherein, when there are multiple air suction devices, each of the air suction devices is evenly arranged on the edge of the contact surface.

[0010] In combination with the first aspect, the embodiment of the present application provides a fifth possible implementation of the first aspect, wherein the system further includes a vacuum pumping device and a vacuum gauge; before executing step S1, the method further includes: After the electrostatic chuck with the wafer fixed thereon is disposed in the closed chamber, controlling the vacuum pumping device to perform a vacuum pumping process on the closed chamber; The vacuum gauge is used to monitor the vacuum degree in the closed chamber in real time, and when the vacuum degree reaches a preset vacuum standard, the vacuum pumping device is controlled to stop the vacuum pumping process.

[0011] In combination with the first aspect, the embodiment of the present application provides a sixth 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 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.

[0012] In combination with the sixth possible implementation of the first aspect, the embodiment of the present application provides a seventh 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:

[0013] 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.

[0014] In combination with the first aspect, the embodiment of the present application provides an eighth 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.

[0015] In a second aspect, an embodiment of the present application further provides a system for testing the electrostatic force of an electrostatic chuck, the system comprising: an electrostatic chuck to be tested, a wafer for testing, a closed chamber, a pressure sensor, a gas pipeline, a gas leakage detector and a data processing module; wherein the wafer is arranged on the electrostatic chuck, and the electrostatic chuck uses electrostatic force to generate a downward adsorption force to fix the wafer; the electrostatic chuck with the wafer fixed is arranged in the closed chamber, and the closed chamber is a vacuum chamber; the gas pipeline is arranged inside the electrostatic chuck, and part of the gas pipeline is evenly distributed on the lower surface of the wafer, and part of the gas pipeline is evenly distributed on the lower surface of the wafer. The pipeline is arranged in affixed relation with the wafer; the gas in the gas pipeline directly contacts the lower surface of the wafer through the gas in the part of the gas pipeline, so that the gas pressure in the gas pipeline generates an upward thrust on the adsorbed wafer; the pressure sensor is used to detect the gas pressure in the gas pipeline; the gas leakage detector is used to detect whether the gas in the gas pipeline leaks into the closed chamber. If the gas in the gas pipeline leaks into the closed chamber, it means that the wafer is subjected to an upward thrust exerted by the gas pressure in the gas pipeline, so that a gap appears between the wafer and the electrostatic chuck; the data processing module is used to execute: Step S1: controlling the gas pressure in the gas pipeline to gradually increase so that the upward thrust force exerted on the adsorbed wafer gradually increases; Step S2: detecting whether the gas in the gas pipeline has leaked into the closed chamber by the gas leakage detector, and determining the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor at the time of gas leakage when the gas leakage detector detects that the gas in the gas pipeline has leaked into the closed chamber; 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.

[0016] The embodiment of the present application provides a method and system for testing the electrostatic force of an electrostatic chuck. First, the test process does not require the introduction of human operation, which is conducive to avoiding errors caused by human operation and improving test accuracy. At the same time, the closed chamber isolates interference from the external environment, and the vacuum environment suppresses gas convection and impurity influences, which is conducive to avoiding interference from the external environment. In addition, the test process is simple to operate and has a high degree of automation, which improves the convenience of the test process. Moreover, a single test takes a short time, and multiple rounds of repeated tests are efficient, which is conducive to shortening the test cycle.

[0017] 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

[0018] 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.

[0019] Figure 1 A side view of a system for testing 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 side view from another perspective of a system for testing electrostatic force of an electrostatic chuck provided in an embodiment of the present application is shown; Figure 4 A schematic diagram showing a layout of three air extraction devices provided in an embodiment of the present application is shown; Figure 5 A schematic cross-sectional view of a single groove pipe provided in an embodiment of the present application is shown; Figure 6 A schematic diagram of the layout of a gas pipeline provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0020] 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.

[0021] Considering that when the electrostatic force of an electrostatic chuck is tested by the pulling method, the test accuracy is low, it is easily interfered by external environmental factors, and the test process is complicated and cumbersome. Based on this, the embodiment of the present application provides a method and system for testing the electrostatic force of an electrostatic chuck to reduce human operation errors, improve test accuracy, avoid interference from the external environment, and improve the convenience of the test process, which is described below through an embodiment.

[0022] 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 test system for the electrostatic force of an electrostatic chuck, such as Figure 1 As shown, the test system of the electrostatic force of the electrostatic chuck also includes: an electrostatic chuck to be tested, a wafer for testing, a closed chamber, a pressure sensor, a gas pipeline, and a gas leakage detector; wherein the wafer is arranged on the electrostatic chuck, and the electrostatic chuck uses electrostatic force to generate a downward adsorption force to fix the wafer; the electrostatic chuck with the wafer fixed is arranged in a closed chamber, and the closed chamber is a vacuum chamber; the gas pipeline is arranged inside the electrostatic chuck, and part of the gas pipeline in the gas pipeline is evenly distributed on the lower surface of the wafer, and part of the gas pipeline is arranged in contact with the wafer; the gas in part of the gas pipeline directly contacts the lower surface of the wafer, so that the gas pressure in the gas pipeline generates an upward thrust on the adsorbed wafer; the pressure sensor is used to detect the gas pressure in the gas pipeline; the gas leakage detector is used to detect whether the gas in the gas pipeline leaks into the closed chamber. If the gas in the gas pipeline leaks into the closed chamber, it means that the wafer is subjected to an upward thrust due to the gas pressure in the gas pipeline, so that a gap appears between the wafer and the electrostatic chuck.

[0023] like Figure 2 As shown, the method comprises the following steps: Step S1: Controlling the gas pressure in the gas pipeline to gradually increase so that the upward thrust force on the adsorbed wafer gradually increases; Step S2: Detecting whether the gas in the gas pipeline has leaked into the closed chamber by a gas leakage detector, and determining the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor at the time of gas leakage when the gas leakage detector detects that the gas in the gas pipeline has leaked into the closed chamber; 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.

[0024] 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.

[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, a gas leakage detector is used to detect in real time whether the gas in the gas pipeline has leaked into the closed chamber. When the gas leakage detector detects that the gas in the gas pipeline has leaked into the closed chamber, 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 the time of gas leakage (i.e. the time when the gas in the gas pipeline leaks into the closed chamber) 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 this embodiment, the pressure sensor is a precision pressure sensor capable of capturing wafer deformation caused by slight changes in electrostatic force.

[0027] In step S3, the effective electrostatic force of the electrostatic chuck can be calculated according to the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor at the time of gas leakage, wherein the effective electrostatic force is used to characterize the maximum adsorption force of the electrostatic chuck on the wafer.

[0028] In this embodiment, the pressure sensor adopts a piezoresistive or capacitive sensor, which is resistant to high temperature and corrosion, and the package is adapted to the chamber environment. The output signal is amplified, filtered, and transmitted to the data processing module after analog-to-digital conversion; the data processing module is equipped with professional testing software and built-in algorithms to realize real-time data processing, visual display, and result storage and printing, and control the coordinated work of various components to automatically complete the testing process.

[0029] The main body of the closed chamber is made of stainless steel, which has high strength and low outgassing characteristics. The inner wall is specially polished and passivated to reduce gas adsorption and secondary reflection interference.

[0030] In a possible implementation, considering that the Czochralski method has poor sensitivity in testing tiny electrostatic forces, it is difficult to accurately reflect the subtle changes in the electrostatic force of the electrostatic chuck, which limits the more in-depth and detailed research and improvement of the performance of the electrostatic chuck. Based on this, the gas in the gas pipeline is helium.

[0031] In this embodiment, based on the small molecular weight and strong diffusion properties of helium, it is equipped with a highly sensitive gas leak detector (when the gas in the gas pipeline is helium, the gas leak detector is a helium detector). It can keenly capture helium leaks caused by tiny displacements and deformations of the wafer, and accurately reflect the subtle fluctuations of the electrostatic force of the electrostatic chuck corresponding to the pressure changes, breaking through the accuracy bottleneck of traditional methods and facilitating the detailed study of the microscopic performance of the electrostatic chuck.

[0032] In this embodiment, helium is stored in a high-pressure steel cylinder, and a gas supply pipeline consisting of a pressure reducer, a filter, a flow controller, and a pressure regulating valve is used to achieve stable and accurate supply of high-purity helium.

[0033] In a possible implementation, the electrostatic chuck adopts a multi-layer composite structure, and the electrode layer, the insulating layer, and the thermal conductive layer are precisely manufactured to ensure uniform electrostatic field and efficient heat conduction.

[0034] The wafer is made of silicon wafers, and the material selection of silicon wafers meets the semiconductor process standards. The flatness and roughness reach the nanometer level. The two are connected and adapted to ensure tight electrostatic adsorption and smooth gas action.

[0035] In a possible embodiment, the test system further comprises at least one air extraction device, such as Figure 1 and Figure 3 As shown, the exhaust device is arranged at the edge of the contact surface between the wafer and the electrostatic chuck; the gas leakage detector is arranged outside the closed chamber; each exhaust device is connected to the gas leakage detector through its corresponding connecting pipe; when executing step S2 to detect whether the gas in the gas pipeline leaks into the closed chamber through the gas leakage detector, the following steps can be specifically performed: The gas near the edge of the contact surface is extracted by the gas extraction device, and the extracted gas is transmitted to the gas leakage detector through the connecting channel, so as to detect whether the gas in the gas pipeline leaks into the closed chamber by the gas leakage detector.

[0036] In this embodiment, each gas extraction device is respectively connected to a connecting pipe, and each connecting pipe is respectively connected to a gas leakage detector.

[0037] In a possible implementation, when there are multiple air extraction devices, each air extraction device is evenly arranged at the edge of the contact surface.

[0038] In this embodiment, Figure 4 A schematic diagram showing the arrangement of the three air extraction devices is shown.

[0039] In a possible implementation, Figure 5 As shown, for each gas extraction device, the gas extraction device includes a single groove pipe, the groove opening of the single groove pipe is arranged toward the edge of the contact surface, and the single groove pipe and the edge of the contact surface constitute an independent space; each single groove pipe is connected to the gas leakage detector through its corresponding connecting pipe; the gas near the edge of the contact surface is extracted by the gas extraction device, and the extracted gas is transported to the gas leakage detector through the connecting channel, including: The gas near the edge of the contact surface is extracted into the single groove pipe of the exhaust device through the exhaust device, and the gas extracted into the single groove pipe is transported to the gas leakage detector through the corresponding connecting channel.

[0040] In this embodiment, when the gas in the gas pipeline is helium, the gas extraction device is a helium extraction device. In this embodiment, the helium extraction device uses a micro vacuum pump and a special sampling tube to efficiently capture leaked helium. The gas leak detector (i.e., helium detector) is based on the principle of mass spectrometry or thermal conductivity detection, and has the characteristics of high sensitivity, fast response, and strong anti-interference, and can accurately monitor helium leakage.

[0041] In a possible implementation manner, the testing system further includes a vacuum pumping device and a vacuum gauge. Before executing step S1, the following steps may be performed: After the electrostatic chuck with the wafer fixed thereon is arranged in the closed chamber, the vacuum pumping device is controlled to perform vacuum pumping treatment on the closed chamber; The vacuum degree in the closed chamber is monitored in real time by a vacuum gauge. When the vacuum degree reaches a preset vacuum standard, the vacuum pumping device is controlled to stop the vacuum pumping process.

[0042] In this embodiment, the vacuum pumping device can be a vacuum pump group integrated with a mechanical pump and a molecular pump, which work together to achieve vacuum pumping of the closed chamber. The vacuum gauge can use a high-precision hot cathode ionization gauge or a capacitive film gauge, which can be switched according to the vacuum range, with real-time digital display and signal output, to provide accurate feedback for vacuum control and ensure the vacuum stability of the closed chamber.

[0043] In a possible implementation manner, when executing step S3 to calculate the effective electrostatic force of the electrostatic chuck according to the pressure value, the following steps may be specifically performed: 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.

[0044] In this embodiment, the test is repeated 5-10 times, and the device is reset at the end of each test. The average pressure value is substituted into the calculation formula to calculate the electrostatic force.

[0045] In a possible implementation manner, when the step of calculating the effective electrostatic force of the electrostatic chuck according to the average pressure value is performed, the following steps may be specifically performed: The effective electrostatic force of the electrostatic chuck is calculated by the following formula:

[0046] 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.

[0047] In a possible implementation, the test system further includes a pressure regulating module, which is connected to the gas inlet of the gas pipeline; when executing step S1 to control the gas pressure in the gas pipeline to gradually increase, the following steps may be specifically performed: A gas pressure regulation instruction is sent to the pressure regulation module, so that the pressure regulation module gradually increases the gas pressure in the gas pipeline according to the gas pressure regulation step length included in the gas pressure regulation instruction.

[0048] Exemplarily, the gas pressure adjustment step may be 0.01 MPa.

[0049] In a possible implementation, Figure 6As 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.

[0050] Based on the same technical concept, an embodiment of the present application also provides a test system for the electrostatic force of an electrostatic chuck, the system comprising: an electrostatic chuck to be tested, a wafer for testing, a closed chamber, a pressure sensor, a gas pipeline, a gas leakage detector and a data processing module; wherein the wafer is arranged on the electrostatic chuck, and the electrostatic chuck uses electrostatic force to generate a downward adsorption force to fix the wafer; the electrostatic chuck with the wafer fixed is arranged in the closed chamber, and the closed chamber is a vacuum chamber; the gas pipeline is arranged inside the electrostatic chuck, and some of the gas pipelines in the gas pipeline are evenly distributed on the lower surface of the wafer, and the part The gas pipeline is arranged in contact with the wafer; the gas in the gas pipeline directly contacts the lower surface of the wafer, so that the gas pressure in the gas pipeline generates an upward thrust on the adsorbed wafer; the pressure sensor is used to detect the gas pressure in the gas pipeline; the gas leakage detector is used to detect whether the gas in the gas pipeline leaks into the closed chamber. If the gas in the gas pipeline leaks into the closed chamber, it means that the wafer is subjected to an upward thrust exerted by the gas pressure in the gas pipeline, so that a gap appears between the wafer and the electrostatic chuck; the data processing module is used to execute: Step S1: controlling the gas pressure in the gas pipeline to gradually increase so that the upward thrust force exerted on the adsorbed wafer gradually increases; Step S2: detecting whether the gas in the gas pipeline has leaked into the closed chamber by the gas leakage detector, and determining the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor at the time of gas leakage when the gas leakage detector detects that the gas in the gas pipeline has leaked into the closed chamber; 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.

[0051] Optionally, the gas in the gas pipeline is helium.

[0052] Optionally, the system further comprises at least one gas extraction device, which is arranged at the edge of the contact surface between the wafer and the electrostatic chuck; the gas leakage detector is arranged outside the closed chamber; each of the gas extraction devices is connected to the gas leakage detector through a corresponding connecting pipe; when the data processing module is used to execute the step of detecting whether the gas in the gas pipeline leaks into the closed chamber through the gas leakage detector, it is specifically used to: The gas near the edge of the contact surface is extracted by the gas extraction device, and the extracted gas is transported to the gas leakage detector through the connecting channel, so that the gas leakage detector can detect whether the gas in the gas pipeline leaks into the closed chamber.

[0053] Optionally, for each of the gas extraction devices, the gas extraction device includes a single-groove pipe, the groove opening of the single-groove pipe is arranged toward the edge of the contact surface, and the single-groove pipe and the edge of the contact surface constitute an independent space; each of the single-groove pipes is connected to the gas leakage detector through a corresponding connecting pipe; when the data processing module is used to execute the step of extracting gas near the edge of the contact surface through the gas extraction device and transporting the extracted gas to the gas leakage detector through the connecting channel, it is specifically used to: The gas near the edge of the contact surface is extracted into the single groove pipe of the gas extraction device through the gas extraction device, and the gas extracted into the single groove pipe is transported to the gas leakage detector through the corresponding connecting channel.

[0054] Optionally, when there are multiple air extraction devices, each of the air extraction devices is evenly arranged on the edge of the contact surface.

[0055] Optionally, the system further comprises a vacuum pumping device and a vacuum gauge; and before the data processing module is used to perform step S1, it is further used to: After the electrostatic chuck with the wafer fixed thereon is disposed in the closed chamber, controlling the vacuum pumping device to perform a vacuum pumping process on the closed chamber; The vacuum gauge is used to monitor the vacuum degree in the closed chamber in real time, and when the vacuum degree reaches a preset vacuum standard, the vacuum pumping device is controlled to stop the vacuum pumping process.

[0056] Optionally, when the data processing module is used to execute step S3 to calculate the effective electrostatic force of the electrostatic chuck according to the pressure value, it is specifically used to: 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.

[0057] 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:

[0058] 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.

[0059] Optionally, the system further comprises a pressure regulating module, the pressure regulating module being connected to the gas inlet of the gas pipeline; when the data processing module is used to execute step S1 to control the gas pressure in the gas pipeline to gradually increase, 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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 for the electrostatic force of an electrostatic chuck, and the system further comprises: an electrostatic chuck to be tested, a wafer for testing, a closed chamber, a pressure sensor, a gas pipeline, and a gas leakage detector; wherein the wafer is arranged on the electrostatic chuck, and the electrostatic chuck uses electrostatic force to generate a downward adsorption force to fix the wafer; the electrostatic chuck with the wafer fixed is arranged in the closed chamber, and the closed chamber is a vacuum chamber; the gas pipeline is arranged inside the electrostatic chuck, and some of the gas pipelines in the gas pipeline are evenly distributed on the lower surface of the wafer, and some of the gas pipelines are evenly distributed on the lower surface of the wafer. The gas pipeline is arranged in a bonding manner with the wafer; the gas in the gas pipeline directly contacts the lower surface of the wafer, so that the gas pressure in the gas pipeline generates an upward thrust on the adsorbed wafer; the pressure sensor is used to detect the gas pressure in the gas pipeline; the gas leakage detector is used to detect whether the gas in the gas pipeline leaks into the closed chamber. If the gas in the gas pipeline leaks into the closed chamber, it means that the wafer is subjected to an upward thrust exerted by the gas pressure in the gas pipeline, so that a gap appears between the wafer and the electrostatic chuck; the method comprises: Step S1: controlling the gas pressure in the gas pipeline to gradually increase so that the upward thrust force exerted on the adsorbed wafer gradually increases; Step S2: detecting whether the gas in the gas pipeline has leaked into the closed chamber by the gas leakage detector, and determining the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor at the time of gas leakage when the gas leakage detector detects that the gas in the gas pipeline has leaked into the closed chamber; 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 gas in the gas pipeline is helium.

3. The method according to claim 1, characterized in that: The system further comprises at least one exhaust device, which is arranged at the edge of the contact surface between the wafer and the electrostatic chuck; the gas leakage detector is arranged outside the closed chamber; each of the exhaust devices is connected to the gas leakage detector through a corresponding connecting pipe; and the gas leakage detector detects whether the gas in the gas pipeline leaks into the closed chamber, including: The gas near the edge of the contact surface is extracted by the gas extraction device, and the extracted gas is transported to the gas leakage detector through the connecting channel, so that the gas leakage detector can detect whether the gas in the gas pipeline leaks into the closed chamber.

4. The method according to claim 3, characterized in that: For each of the gas extraction devices, the gas extraction device includes a single groove pipe, the groove opening of the single groove pipe is arranged toward the edge of the contact surface, and the single groove pipe and the edge of the contact surface constitute an independent space; each of the single groove pipes is connected to the gas leakage detector through a corresponding connecting pipe; the gas near the edge of the contact surface is extracted by the gas extraction device, and the extracted gas is transported to the gas leakage detector through the connecting channel, including: The gas near the edge of the contact surface is extracted into the single groove pipe of the gas extraction device through the gas extraction device, and the gas extracted into the single groove pipe is transported to the gas leakage detector through the corresponding connecting channel.

5. The method according to claim 3, characterized in that: When there are multiple air extraction devices, each of the air extraction devices is evenly arranged on the edge of the contact surface.

6. The method according to claim 1, characterized in that: The system further includes a vacuum pump and a vacuum gauge; before performing step S1, the method further includes: After the electrostatic chuck with the wafer fixed thereon is disposed in the closed chamber, controlling the vacuum pumping device to perform a vacuum pumping process on the closed chamber; The vacuum gauge is used to monitor the vacuum degree in the closed chamber in real time, and when the vacuum degree reaches a preset vacuum standard, the vacuum pumping device is controlled to stop the vacuum pumping process.

7. 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.

8. The method according to claim 7, 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.

9. 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.

10. A system for testing the electrostatic force of an electrostatic chuck, characterized in that: The system comprises: an electrostatic chuck to be tested, a wafer for testing, a closed chamber, a pressure sensor, a gas pipeline, a gas leakage detector and a data processing module; wherein the wafer is arranged on the electrostatic chuck, and the electrostatic chuck uses electrostatic force to generate a downward adsorption force to fix the wafer; the electrostatic chuck with the wafer fixed is arranged in the closed chamber, and the closed chamber is a vacuum chamber; the gas pipeline is arranged inside the electrostatic chuck, and some of the gas pipelines in the gas pipeline are evenly distributed on the lower surface of the wafer, and some of the gas pipelines are arranged in contact with the wafer; by The gas in the part of the gas pipeline directly contacts the lower surface of the wafer, so that the gas pressure in the gas pipeline generates an upward thrust on the adsorbed wafer; the pressure sensor is used to detect the gas pressure in the gas pipeline; the gas leakage detector is used to detect whether the gas in the gas pipeline leaks into the closed chamber. If the gas in the gas pipeline leaks into the closed chamber, it means that the wafer is subjected to an upward thrust exerted by the gas pressure in the gas pipeline, so that a gap appears between the wafer and the electrostatic chuck; the data processing module is used to execute: Step S1: controlling the gas pressure in the gas pipeline to gradually increase so that the upward thrust force exerted on the adsorbed wafer gradually increases; Step S2: detecting whether the gas in the gas pipeline has leaked into the closed chamber by the gas leakage detector, and determining the pressure value of the gas pressure in the gas pipeline detected by the pressure sensor at the time of gas leakage when the gas leakage detector detects that the gas in the gas pipeline has leaked into the closed chamber; 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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