A method of endocardial electrode gap lift calibration

Abstract

The application discloses a method for calibrating the gap of an intracavity electrode, which is used to realize the synchronous calibration of the gap of the intracavity electrode in the aspects of lifting and posture, and improve the accuracy and consistency of actual etching conditions. The method comprises the following steps: based on the target electrode gap height, assembling and initially setting the height of a calibration jig; arranging the calibration jig on the surface of an electrostatic chuck process platform, and internally installing a reference plane assembly corresponding to the position of an upper cavity electrode above the etching cavity; closing the etching cavity, when the electrostatic chuck process platform reaches a preset process height position, exerting axial pressure on the calibration jig by using the reference plane assembly, so that the calibration jig generates self-adaptive contraction displacement degree by overcoming the friction damping; opening the etching cavity, obtaining the height measurement data of the locked calibration jig by using a measurement tool, and establishing the parallelism model of the electrostatic chuck process platform relative to the reference plane assembly, so as to complete the lifting calibration of the gap of the intracavity electrode.

Description

Technical Field

[0001] This application relates to the technical field of semiconductor etching, and more particularly to a method for calibrating the rise and fall of intracavity electrode gaps. Background Technology

[0002] In semiconductor etching equipment, the electrode gap height between the upper electrode inside the etching chamber and the electrostatic chuck process platform has a significant impact on etching uniformity, plasma stability, and process repeatability. This electrode gap is typically adjusted using the lifting mechanism of the electrostatic chuck process platform and calibrated during equipment commissioning or maintenance to meet the process requirements of different etching processes.

[0003] In existing technologies, electrode gap calibration typically relies on mechanical calibration benchmarks or single-point height settings. Even when the electrostatic chuck process platform is raised or lowered to a preset position, the actual electrode gap between the upper electrode and the process platform may still vary at different locations, affecting the consistency of the etching process. Furthermore, when the etching chamber is closed, the electrode gap cannot be directly observed or measured. Existing calibration methods can only indirectly confirm the gap in some cases when the chamber is open or under non-actual operating conditions, failing to accurately reflect the actual electrode gap when the chamber is closed and the process platform is at the true process height, thus affecting the etching effect. Summary of the Invention

[0004] This application provides a method for calibrating the lifting and lowering of the intracavity electrode gap, which enables synchronous calibration of the intracavity electrode gap at the lifting and lowering and attitude levels, thereby improving the accuracy and consistency of actual etching conditions.

[0005] This application provides a method for calibrating the intracavity electrode gap adjustment, including:

[0006] Based on the process requirements of the etching process, determine the target electrode gap height between the upper cavity electrode and the electrostatic chuck process platform; Based on the target electrode gap height, at least three height-adjustable calibration fixtures are assembled and their initial height is set. The friction damping inside the calibration fixtures is adjusted, and the initial height of the calibration fixtures is made greater than the target electrode gap height. The calibration fixture is arranged on the surface of the electrostatic chuck process platform according to a predetermined geometric distribution rule, and a reference plane component corresponding to the position of the upper cavity electrode is installed inside the upper cavity. The etching cavity is closed, and the electrostatic chuck process platform is driven to rise slowly. When the electrostatic chuck process platform reaches the preset process height position, the reference plane component is used to apply axial pressure to the calibration fixture, so that the calibration fixture overcomes the friction damping and generates an adaptive contraction displacement, so as to physically record the actual electrode gap height at the corresponding position. Open the etching cavity, remove the calibration fixture from the electrostatic chuck process platform, and mechanically lock the movable parts of the calibration fixture. The height measurement data of the locked calibration fixture is obtained using a measuring tool, and a parallelism model of the electrostatic chuck process platform relative to the reference plane assembly is established based on the height measurement data from multiple locations. The pitch angle, tilt angle, or vertical height of the electrostatic chuck process platform are adjusted based on the deviation value output by the parallelism model to complete the lifting and lowering calibration of the electrode gap inside the cavity.

[0007] Optionally, the calibration fixture consists of a fixed base, a sliding shaft, and an adjusting screw. The fixed base is provided with a guide hole for inserting the sliding shaft and a threaded hole for installing the adjusting screw. The assembly of at least three height-adjustable calibration fixtures includes: Insert the sliding shaft into the guide hole and screw in the adjusting screw so that the end of the adjusting screw abuts against the surface of the sliding shaft; The clamping force of the fixed base on the sliding shaft is controlled by rotating the adjusting screw, and the damping force threshold of the sliding shaft when it moves under pressure is set to ensure that the damping force threshold is greater than the weight of the sliding shaft itself and less than the axial pressure applied by the reference plane assembly.

[0008] Optionally, both the fixed base and the sliding shaft are made of polyetheretherketone (PEEK).

[0009] 4. The method according to claim 2, characterized in that, the mechanical locking of the movable parts of the calibration fixture specifically includes: Tighten the adjusting screw further to increase the static friction between the sliding shaft and the fixed base, so as to keep the relative position of the sliding shaft and the fixed base fixed.

[0010] Optionally, the initial height setting of at least three height-adjustable calibration fixtures includes: The total height of the calibration fixture was monitored in real time using vernier calipers. During the adjustment process, the initial height of the calibration fixture is adjusted to within the preset tolerance range of the target electrode gap height to ensure that the calibration fixture has sufficient compression stroke to adapt to the actual electrode gap height.

[0011] Optionally, arranging the calibration fixture on the surface of the electrostatic chuck process platform according to a predetermined geometric distribution rule includes: Select four sets of calibration fixtures that have been adjusted and tested; The four sets of calibration fixtures are placed at the 3 o'clock, 6 o'clock, 9 o'clock and 12 o'clock positions on the electrostatic chuck process platform, respectively. Adjust the position of each set of calibration fixtures so that they are 2 cm away from the edge of the electrostatic chuck process platform.

[0012] Optionally, obtaining the height measurement data of the locked calibration fixture includes: Use a vernier caliper or micrometer to measure the final total height of the four sets of calibration fixtures located at the 3 o'clock, 6 o'clock, 9 o'clock and 12 o'clock positions.

[0013] Optionally, adjusting the pitch angle, tilt angle, or vertical height of the electrostatic chuck process platform based on the deviation value output by the parallelism model includes: Calculate the height difference between the calibration fixture at the 3 o'clock and 9 o'clock positions to determine the flipping deviation of the electrostatic chuck process platform in the first axis. Calculate the height difference between the calibration fixture at the 6 o'clock and 12 o'clock positions to determine the pitch deviation of the electrostatic chuck process platform in the second axis. Based on the tilting and pitching deviations, adjust the mechanical support mechanism at the bottom of the electrostatic chuck process platform until the height measurement data in all four directions are consistent.

[0014] Optionally, the step of mounting a reference plane assembly corresponding to the position of the upper cavity electrode inside the upper cavity includes: A dummy flat electrode fixture is installed inside the upper part of the etching cavity as the reference plane assembly. The dummy flat electrode fixture has a lower surface flatness consistent with that of the actual electrode in the process.

[0015] Optionally, applying axial pressure to the calibration fixture using the reference plane assembly, causing the calibration fixture to overcome the frictional damping and generate an adaptive contraction displacement, to physically record the actual electrode gap height at the corresponding position, includes: During the ascent of the electrostatic chuck process platform, when the top of the calibration fixture contacts the reference plane assembly, the sliding shaft slides downward relative to the fixed base under pressure. When the electrostatic chuck process platform stops at the process height position, the sliding shaft stops sliding and uses the friction damping to maintain the current height, thereby achieving mechanical memory of the actual gap at the current position.

[0016] As can be seen from the above technical solutions, this application has the following advantages: In the actual operating state where the etching cavity is closed and the electrostatic chuck process platform is at the process height, the actual electrode gap height at different positions is recorded using a height-adjustable calibration fixture under axial pressure. After the height state is locked, the corresponding height measurement data is obtained, thereby converting the electrode gap information inside the cavity, which cannot be directly obtained, into measurable physical dimension data. Based on the height measurement data from multiple positions, the spatial attitude of the electrostatic chuck process platform relative to the upper cavity electrode reference plane is analyzed as a whole. Based on this, the pitch angle, roll angle, or vertical height of the electrostatic chuck process platform is adjusted, so that the electrode gap calibration process covers multiple positions and reflects the overall attitude relationship of the platform. This enables synchronous calibration of the electrode gap inside the cavity at the lifting and attitude levels, improving the accuracy and consistency of the actual etching conditions. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic flowchart of an embodiment of the method for calibrating the intracavity electrode gap height adjustment provided in this application; Figure 2 A schematic diagram of the calibration fixture used in the method for calibrating the lifting and lowering of the intracavity electrode gap provided in this application. Detailed Implementation

[0019] In this application, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and other terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to describe the relative positional relationship between the components or parts and do not specifically limit the specific installation orientation of each component or part.

[0020] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0021] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0022] Furthermore, the structures, proportions, sizes, etc., drawn in the accompanying drawings of this application are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modification to the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects and purposes that this application can produce, should still fall within the scope of the technical content disclosed in this application.

[0023] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] Please see Figure 1 and Figure 2 , Figure 1 This is one embodiment of the method for calibrating the intracavity electrode gap adjustment provided in this application. Figure 2 This is a schematic diagram of the calibration fixture used in this application. The method includes: 101. Determine the target electrode gap height between the upper cavity electrode and the electrostatic chuck process platform according to the etching process requirements; In this embodiment, the uniformity of the etching process is closely related to the electrode gap (GAP), and different process formulations correspond to different optimal gap values. First, it is necessary to confirm the theoretically ideal vertical distance between the upper cavity electrode and the electrostatic chuck (ESC) process platform during the current process, i.e., the target electrode gap height. This value serves as the benchmark reference for subsequent fixture height preset calibration, ensuring that the measurement range covers actual operating conditions.

[0025] 102. Based on the target electrode gap height, assemble and initially set the height of at least three height-adjustable calibration fixtures, adjust the internal friction damping of the calibration fixtures, and make the initial height of the calibration fixtures greater than the target electrode gap height. In this embodiment, a calibration fixture with height adjustment and memory functions is used. Before use, its internal friction damping needs to be adjusted. The function of this friction damping is: 1. The resistance must be large enough to prevent the movable parts of the fixture from shifting under gravity or slight vibration; 2. The resistance must be less than the externally applied axial pressure to ensure that a contraction action can occur during calibration. Simultaneously, the initial height of the calibration fixture must be set greater than the target electrode gap height. This is because this application utilizes the principle of compression and retraction; only when the fixture height is higher than the actual gap can the reference plane component contact and compress the fixture during cavity closure. If the initial height is less than the actual gap, the fixture will not be able to contact the reference plane, resulting in the inability to obtain valid data.

[0026] 103. Arrange the calibration fixture on the surface of the electrostatic chuck process platform according to the predetermined geometric distribution rules, and install the reference plane component corresponding to the position of the upper cavity electrode inside the upper cavity. In this embodiment, the calibration fixture is placed on the electrostatic chuck process platform according to a predetermined geometric distribution rule, such as circumferential, symmetrical, or array distribution, to cover critical areas of the process platform, such as edges or centers. Simultaneously, a reference plane assembly is disposed inside the etching cavity above it. The position of this reference plane assembly corresponds to the position of the upper cavity electrode in the actual process, or is the upper cavity electrode itself; its function is to provide a physical reference surface for pressing the calibration fixture downwards in subsequent steps.

[0027] 104. Close the etching cavity and drive the electrostatic chuck process platform to rise slowly. When the electrostatic chuck process platform reaches the preset process height position, use the reference plane component to apply axial pressure to the calibration fixture, so that the calibration fixture overcomes frictional damping and generates adaptive contraction displacement, so as to physically record the actual electrode gap height at the corresponding position. In this embodiment, a closed cavity is used to drive an electrostatic chuck process platform upward, simulating the mechanical motion state during actual production. When the platform rises to a preset process height, because the initial height of the fixture is greater than the actual gap, the top of the fixture will first contact the reference plane component above. As the platform continues to rise to the endpoint, the reference plane component applies axial pressure to the fixture, forcing the movable parts of the fixture to overcome preset frictional damping and generate a contraction displacement relative to the fixture body. When the platform stops moving, the height of the fixture is equivalent to being compressed to the current actual electrode gap height. This process enables the adaptive recording of physical gap dimensions through a purely mechanical means in a closed, invisible environment.

[0028] 105. Open the etching chamber, remove the calibration fixture from the electrostatic chuck process platform, and mechanically lock the movable parts of the calibration fixture. In this embodiment, after recording is completed, the electrostatic chuck process platform descends, opening the cavity. The operator removes the calibration fixture containing the recorded height data. To prevent displacement of movable parts due to external force or inertia during fixture removal or subsequent transfer, which could corrupt the recorded data, the movable parts of the calibration fixture can be mechanically locked immediately upon removal. This locking operation solidifies the fixture's current height status, ensuring the accuracy of subsequent measurements.

[0029] 106. Use measuring tools to obtain height measurement data of the locked calibration fixture, and based on the height measurement data of multiple locations, establish a parallelism model of the electrostatic chuck process platform relative to the reference plane assembly. In this embodiment, a measuring tool with appropriate accuracy is used to measure the height of each locked calibration fixture, obtaining values ​​representing the actual gaps at each arrangement point. Based on these height data distributed at different locations, a parallelism model is established through geometric calculations or spatial analysis. This model can quantify the spatial attitude of the electrostatic chuck process platform relative to the reference plane assembly, identify whether the platform is tilted, and the direction and degree of tilt.

[0030] 107. Adjust the pitch angle, tilt angle or vertical height of the electrostatic chuck process platform according to the deviation value output by the parallelism model to complete the lifting and lowering calibration of the electrode gap in the cavity.

[0031] In this embodiment, the specific adjustment strategy is determined based on the deviation values ​​calculated by the parallelism model, including height difference and tilt angle. For the mechanical adjustment mechanism of the electrostatic chuck process platform, the pitch angle, tilt angle, or overall vertical height are corrected until the deviation is eliminated, ensuring that the actual electrode gap height at each position is consistent or meets the preset tolerance range. This completes the calibration of the intracavity electrode gap, ensuring the consistency of the etching process.

[0032] In this embodiment, the target electrode gap height is first determined according to the specific process requirements of the etching process, and a height-adjustable calibration fixture is prepared based on this. During the assembly and setup stage, the friction damping inside the calibration fixture is adjusted so that it can be compressed while maintaining its position, and the initial height is set higher than the target value. Next, multiple calibration fixtures are distributed and placed on the surface of the electrostatic chuck process platform according to specific geometric rules, and a reference plane assembly is established above the cavity. Then, the cavity is closed, the electrostatic chuck process platform is driven to rise to the process height, and the upper reference plane assembly is used to press down on the calibration fixture, causing it to overcome the damping and generate adaptive contraction, thereby physically recording the actual gap height at that position. Afterwards, the cavity is opened and the calibration fixture is removed, and the movable parts are immediately mechanically locked to fix the data, and then the height value is read using a measuring tool. Finally, a parallelism model is established based on the multi-point height data, the deviation is analyzed, and the pitch, tilt, or height of the electrostatic chuck process platform is adjusted accordingly to complete the calibration.

[0033] The method provided in this embodiment can record the actual electrode gap height at different positions under axial pressure conditions using a height-adjustable calibration fixture in a real operating state where the etching cavity is closed and the electrostatic chuck process platform is at the process height. After the height state is locked, the corresponding height measurement data is obtained, thereby converting the electrode gap information inside the cavity, which cannot be directly obtained, into measurable physical dimension data. Based on the height measurement data from multiple positions, the spatial attitude of the electrostatic chuck process platform relative to the upper cavity electrode reference plane is analyzed as a whole, and the pitch angle, roll angle, or vertical height of the electrostatic chuck process platform is adjusted accordingly. This allows the electrode gap calibration process to cover multiple positions and reflect the overall attitude relationship of the platform, thereby achieving synchronous calibration of the electrode gap inside the cavity at the lifting and attitude levels, improving the accuracy and consistency of the actual etching conditions.

[0034] In step 102, at least three height-adjustable calibration fixtures are assembled and their initial height is set, specifically involving the selection of the mechanical structure and materials of the calibration fixtures. Please refer to [link to relevant documentation]. Figure 2 In a preferred embodiment of this application, the calibration fixture adopts a purely mechanical structure, mainly composed of a fixed base, a sliding shaft, and an adjusting screw. During assembly, the sliding shaft is inserted into the guide hole in the center of the fixed base. Due to the clearance fit design, the sliding shaft can slide freely up and down within the guide hole. Subsequently, the adjusting screw is screwed into the threaded hole on the side wall of the fixed base, so that its end abuts against the surface of the sliding shaft. By rotating the adjusting screw, the clamping force of the fixed base on the sliding shaft can be controlled. The principle for setting this damping force threshold is: the damping force must be greater than the weight of the sliding shaft itself to ensure that the sliding shaft will not slip when the fixture is moved or inverted; simultaneously, the damping force must be less than the axial pressure applied by the reference plane assembly to ensure that the sliding shaft can retract smoothly during ESC upward compression.

[0035] Furthermore, considering that the calibration process is performed on a precision ESC process platform, to prevent hard metal from scratching the anodized or ceramic coating on the ESC surface, the fixed base and sliding shaft are preferably made of polyetheretherketone (PEEK). PEEK material not only has excellent wear and corrosion resistance, but also moderate hardness, which ensures the rigidity of the measurement structure and protects the expensive cavity components during contact.

[0036] Furthermore, when setting the initial height of the calibration fixture, a vernier caliper is required to monitor the total height of the fixture in real time. The operator must adjust the initial height of the fixture to within the preset tolerance range of the target electrode gap height. For example, if the target GAP is 25mm, the initial height can be set between 27mm and 30mm. The purpose of this setting is to ensure that the calibration fixture has sufficient compression stroke, such as a compression amount of 2-5mm, to match the actual electrode gap height and prevent the fixture from being suspended in mid-air due to insufficient initial height, thus preventing data recording.

[0037] In step 103, when arranging the calibration fixtures on the surface of the electrostatic chuck process platform, in a preferred embodiment of this application, four sets of calibrated calibration fixtures can be selected to comprehensively capture the tilt attitude of the ESC plane. These four sets of fixtures are placed at the 3 o'clock, 6 o'clock, 9 o'clock, and 12 o'clock positions of the electrostatic chuck process platform, respectively. Furthermore, to improve the sensitivity of tilt angle measurement, the position of each set of calibration fixtures can be adjusted so that it is 2 cm away from the edge of the electrostatic chuck process platform. The reason for choosing the edge position rather than the center position is that the linear displacement amplification effect of the ESC platform's tilt is most obvious at the edge, and the measurement at this location can obtain the highest sensitivity, thereby capturing small angular deviations and improving calibration accuracy.

[0038] Furthermore, when installing the reference plane assembly inside the upper part of the etching cavity, in order to eliminate interference from potential surface wear or uneven installation of the original electrode on the machine, it is preferable to install a dummy flat electrode fixture as the reference plane assembly inside the upper part of the etching cavity. This dummy flat electrode fixture is processed to have extremely high flatness, and its lower surface is consistent with the height position of the electrode in the actual process, thereby providing an ideal zero-position surface.

[0039] In step 104, as a preferred embodiment of this application, during the process of the electrostatic chuck process platform driving the fixture upward, when the top of the calibration fixture, i.e., the top of the sliding shaft, first contacts the reference plane assembly, the reference plane assembly applies reverse pressure to the sliding shaft as the ESC continues to rise. At this time, the sliding shaft overcomes the preset frictional damping and slides downward relative to the fixed base. When the electrostatic chuck process platform finally stops at the preset process height position, the sliding shaft also stops sliding. At this time, using the preset static friction force of the adjusting screw, the sliding shaft can stop at the current position and no longer bounce back or slip, thereby realizing the mechanical memory of the actual gap GAP at that specific position.

[0040] In step 105, mechanically locking the movable parts of the calibration fixture is to ensure data reliability. In a preferred embodiment of this application, after opening the cavity and removing the fixture, and before measurement, the operator needs to further tighten the adjusting screw. This action eliminates any minor clearance that may exist between the sliding shaft and the fixed base, significantly increases frictional resistance, and completely fixes the relative position of the sliding shaft and the fixed base. This effectively prevents measurement errors caused by displacement of the sliding shaft due to external force disturbance during subsequent caliper contact measurement.

[0041] In step 106, as a preferred embodiment of this application, a vernier caliper or micrometer with an accuracy of at least 0.02 mm (preferably 0.01 mm) is used to measure the final total height of four sets of calibration fixtures located at the 3 o'clock, 6 o'clock, 9 o'clock, and 12 o'clock positions, respectively, and denoted as H3, H6, H9, and H12. These data directly reflect the actual distance between each point on the edge of the ESC and the upper electrode under the process conditions.

[0042] In step 107, the specific deviation analysis and adjustment logic is as follows: First, calculate the height difference between the calibration fixture at the 3 o'clock and 9 o'clock positions: H_roll = |H_3 - H_9|, and this difference reflects the degree of tilt of the platform in the left and right directions.

[0043] Next, calculate the height difference between the calibration fixture at the 6 o'clock and 12 o'clock positions: H_pitch = |H_6 - H_12|, and this difference reflects the degree of tilt of the platform in the forward and backward directions.

[0044] Based on the calculated tilt and pitch deviations, the operator or automatic control system makes targeted adjustments to the mechanical support mechanisms at the bottom of the electrostatic chuck platform, such as the three-axis leveling nut and electric push rod. The goal of the adjustment is to make the height measurement data in the four directions consistent, i.e., H_3≈H_6≈H_9≈H_12, thereby achieving parallelism between the ESC platform and the upper electrode and completing the calibration of the electrode gap within the cavity.

[0045] It should be noted that the above description of the disclosed embodiments enables those skilled in the art to implement or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for calibrating the lifting and lowering of the intracavity electrode gap, characterized in that, The method includes: Based on the process requirements of the etching process, determine the target electrode gap height between the upper cavity electrode and the electrostatic chuck process platform; Based on the target electrode gap height, at least three height-adjustable calibration fixtures are assembled and their initial height is set. The friction damping inside the calibration fixtures is adjusted, and the initial height of the calibration fixtures is made greater than the target electrode gap height. The calibration fixture is arranged on the surface of the electrostatic chuck process platform according to a predetermined geometric distribution rule, and a reference plane component corresponding to the position of the upper cavity electrode is installed inside the upper cavity. The etching cavity is closed, and the electrostatic chuck process platform is driven to rise slowly. When the electrostatic chuck process platform reaches the preset process height position, the reference plane component is used to apply axial pressure to the calibration fixture, so that the calibration fixture overcomes the friction damping and generates an adaptive contraction displacement, so as to physically record the actual electrode gap height at the corresponding position. Open the etching cavity, remove the calibration fixture from the electrostatic chuck process platform, and mechanically lock the movable parts of the calibration fixture. The height measurement data of the locked calibration fixture is obtained using a measuring tool, and a parallelism model of the electrostatic chuck process platform relative to the reference plane assembly is established based on the height measurement data from multiple locations. The pitch angle, tilt angle, or vertical height of the electrostatic chuck process platform are adjusted based on the deviation value output by the parallelism model to complete the lifting and lowering calibration of the electrode gap inside the cavity.

2. The method according to claim 1, characterized in that, The calibration fixture consists of a fixed base, a sliding shaft, and an adjusting screw. The fixed base is provided with a guide hole for inserting the sliding shaft and a threaded hole for installing the adjusting screw. The assembly of at least three height-adjustable calibration fixtures includes: Insert the sliding shaft into the guide hole and screw in the adjusting screw so that the end of the adjusting screw abuts against the surface of the sliding shaft; The clamping force of the fixed base on the sliding shaft is controlled by rotating the adjusting screw, and the damping force threshold of the sliding shaft when it moves under pressure is set to ensure that the damping force threshold is greater than the weight of the sliding shaft itself and less than the axial pressure applied by the reference plane assembly.

3. The method according to claim 2, characterized in that, Both the fixed base and the sliding shaft are made of polyetheretherketone (PEEK).

4. The method according to claim 2, characterized in that, The mechanical locking of the movable parts of the calibration fixture specifically includes: Tighten the adjusting screw further to increase the static friction between the sliding shaft and the fixed base, so as to keep the relative position of the sliding shaft and the fixed base fixed.

5. The method according to claim 1, characterized in that, The initial height setting for at least three height-adjustable calibration fixtures includes: The total height of the calibration fixture was monitored in real time using vernier calipers. During the adjustment process, the initial height of the calibration fixture is adjusted to within the preset tolerance range of the target electrode gap height to ensure that the calibration fixture has sufficient compression stroke to adapt to the actual electrode gap height.

6. The method according to claim 1, characterized in that, The step of arranging the calibration fixture on the surface of the electrostatic chuck process platform according to a predetermined geometric distribution rule includes: Select four sets of calibration fixtures that have been adjusted and tested; The four sets of calibration fixtures are placed at the 3 o'clock, 6 o'clock, 9 o'clock and 12 o'clock positions on the electrostatic chuck process platform, respectively. Adjust the position of each set of calibration fixtures so that they are 2 cm away from the edge of the electrostatic chuck process platform.

7. The method according to claim 6, characterized in that, The process of obtaining the height measurement data of the locked calibration fixture includes: Use a vernier caliper or micrometer to measure the final total height of the four sets of calibration fixtures located at the 3 o'clock, 6 o'clock, 9 o'clock and 12 o'clock positions.

8. The method according to claim 7, characterized in that, The step of adjusting the pitch angle, tilt angle, or vertical height of the electrostatic chuck process platform based on the deviation value output by the parallelism model includes: Calculate the height difference between the calibration fixture at the 3 o'clock and 9 o'clock positions to determine the flipping deviation of the electrostatic chuck process platform in the first axis. Calculate the height difference between the calibration fixture at the 6 o'clock and 12 o'clock positions to determine the pitch deviation of the electrostatic chuck process platform in the second axis. Based on the tilting and pitching deviations, adjust the mechanical support mechanism at the bottom of the electrostatic chuck process platform until the height measurement data in all four directions are consistent.

9. The method according to any one of claims 1 to 8, characterized in that, The method of installing a reference plane assembly corresponding to the position of the upper cavity electrode inside the upper cavity includes: A dummy flat electrode fixture is installed inside the upper part of the etching cavity as the reference plane assembly. The dummy flat electrode fixture has a lower surface flatness consistent with that of the actual electrode in the process.

10. The method according to any one of claims 1 to 8, characterized in that, The step of applying axial pressure to the calibration fixture using the reference plane assembly, causing the calibration fixture to overcome the frictional damping and generate an adaptive contraction displacement, in order to physically record the actual electrode gap height at the corresponding position, includes: During the ascent of the electrostatic chuck process platform, when the top of the calibration fixture contacts the reference plane assembly, the sliding shaft slides downward relative to the fixed base under pressure. When the electrostatic chuck process platform stops at the process height position, the sliding shaft stops sliding and uses the friction damping to maintain the current height, thereby achieving mechanical memory of the actual gap at the current position.

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