A method for processing micro-curved surface profile of electrostatic chuck ceramic surface
By combining polishing and sandblasting, the problems of insufficient precision and high cost in micro-surface machining of electrostatic chuck ceramic surfaces were solved, efficient and low-cost micro-surface machining was achieved, and the uniformity and polishing quality of the product surface were improved.
Patent Information
- Application Number
- CN202310856205.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-12
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2043-07-12
AI Technical Summary
In the existing technology, the processing accuracy of the micro-curved surface profile of the electrostatic chuck ceramic surface is insufficient and the cost is too high. Traditional machine tool processing methods are difficult to ensure high precision and are expensive.
A combination of polishing and sandblasting is used to first flat-polish the ceramic surface of the electrostatic chuck, then use a sandblaster to form a contour surface on the rotating electrostatic chuck, and finally use a flexible polishing device to perform contour polishing. The movement path and speed of the sandblasting machine nozzle are controlled to ensure accuracy and avoid sand accumulation, and a flexible polishing device is used to fit the concave contour.
It achieves the goal of reducing production costs while stably obtaining micro-curved surface profiles that meet standards, improving the uniformity and polishing quality of product surfaces, reducing the frequency of equipment replacement and processing faults, and improving fault tolerance.
Smart Images
Figure CN117001539B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to a method for processing a micro-curved surface profile of an electrostatic chuck ceramic surface. Background Art
[0002] The electrostatic adsorption technology used in electrostatic chucks (ESCs) is an advantageous alternative to traditional mechanical clamping and vacuum adsorption methods, and is widely used in fields such as semiconductors, panel displays, and optics. The basic principle of ESCs is the mutual attraction between oppositely directed charges. Specifically, the Coulomb force between the dissimilar charges attracts the wafer and the electrode, stabilizing the wafer on the electrode. Electrostatic chucks play a crucial role in semiconductor production, leading to the widespread research and development of these devices.
[0003] For example, publication number "CN104241182B" discloses a "manufacturing method of an electrostatic chuck, an electrostatic chuck, and a plasma processing device," which includes the following steps: manufacturing the main body and base of the electrostatic chuck, wherein the steps of manufacturing the main body include, in sequence: step S11: forming a ceramic substrate embedded with a thin film electrode; step S12: patterning the upper surface of the ceramic substrate; and step S13: depositing a patterned plasma-resistant protective layer on the ceramic substrate to form the main body of the electrostatic chuck; and then connecting the main body and the base to form the electrostatic chuck. However, in actual applications, a concave contour is machined on the ceramic surface according to practical needs. The use of traditional machine tool processing methods cannot guarantee qualified processing accuracy, and the technical cost is too high. Summary of the Invention
[0004] In response to the problems of insufficient contour processing accuracy and high cost in the existing technology mentioned in the background technology, the present invention provides a method for processing the micro-curved surface contour of the electrostatic chuck ceramic surface, which can stably obtain a micro-curved surface contour that meets the standards, and improve the uniformity of the product surface through a sandblasting process. At the same time, there is no need to use high-cost ultra-high precision machine tools, thereby reducing production costs.
[0005] To achieve the above objectives, the present invention adopts the following technical solutions.
[0006] A method for machining a micro-curved surface profile of an electrostatic chuck ceramic surface comprises the following steps:
[0007] S1. Using a polishing agent to plane-polish the ceramic surface of the electrostatic chuck;
[0008] S2, rotating the electrostatic chuck and simultaneously moving the sandblasting nozzle, which is located above the electrostatic chuck and moves in a direction transverse to the electrostatic chuck, to sandblast the surface of the electrostatic chuck to form a contour surface;
[0009] S3. Use a flexible polishing device to perform contour polishing on the contour surface processed in step S2. First, the surface of the electrostatic chuck is polished to obtain a very flat surface, providing a good foundation for subsequent sandblasting. The concave contour processing of each part on the electrostatic chuck can obtain a consistent positioning reference. The sandblasting process can well maintain the uniformity of the surface. Although there will be slight differences during the sandblasting process, they can be corrected through subsequent contour polishing. The processing process is relatively gentle. Compared with the machine tool processing in the existing technology, it not only saves the high cost of the processing equipment itself, but also improves the fault tolerance rate. During the sandblasting process, the electrostatic chuck is prevented from automatically rotating on the turntable. The sandblasting machine nozzle is controlled to translate horizontally across the top of the electrostatic chuck. During the rotation of the electrostatic chuck, the ceramic surface of the electrostatic chuck is simultaneously contoured, resulting in a uniform concave contour. The precision requirements for the processing equipment are not high, and the cost of regular replacement of processing equipment to maintain processing accuracy is also avoided. After the contour sandblasting process is completed, the flexible polishing device is used to better fit the concave contour. The contour polishing process of the concave contour avoids missing corners and arcs, thereby improving the polishing quality.
[0010] In step S2, the movement path of the sandblasting machine nozzle when sandblasting the electrostatic chuck includes several speed control intervals, and the movement speed of the sandblasting machine nozzle varies in each speed control interval. The sandblasting machine nozzle has different translation speeds in different speed control intervals, which can better adapt to the rotating electrostatic chuck and ensure that the degree of sandblasting on each area of the electrostatic chuck is within a controllable range. If the sandblasting machine nozzle moves at a uniform speed, the sandblasting area becomes smaller as it moves towards the center, and because of the uniform speed sandblasting, the time it takes to spray each area becomes longer and longer. Although a concave contour in the middle is formed, it cannot meet the 5μm-10μm requirement. The speed change between the speed control intervals can be stepless to ensure a smooth transition between the speed control intervals.
[0011] The speed control intervals are set to x, 80≤x≤120. By setting the speed control intervals within this range, the contour processing accuracy can be controlled by controlling the speed without causing machining faults on the continuous contour surface, thereby ensuring the quality of the processed contour surface and reducing the difficulty of subsequent contour polishing.
[0012] In step S2, there is an offset distance between the movement path of the sandblasting machine nozzle on the electrostatic chuck and the center of the electrostatic chuck. The sandblasting machine nozzle has a blasting range. The "offset spacing" refers to the offset gap between the center of the blasting range and the center of the electrostatic chuck. However, the blasting range will still cover the center of the electrostatic chuck, thereby ensuring that a complete contour surface can be processed. Since the rotation of the electrostatic chuck will generate centrifugal force, if the sandblasting machine nozzle passes directly through the center of the circle, the sand and gravel ejected by the sandblasting machine nozzle will be too symmetrical on the electrostatic chuck. When passing through the center of the circle, the force area between the various gravel attached to the center of the electrostatic chuck will be balanced, resulting in some gravel that cannot be thrown out in the center of the electrostatic chuck, which in turn makes it impossible to obtain an ideal contour in the center of the circle. When an offset occurs between the sandblasting area and the center of the electrostatic chuck, this balance will be broken, and there will be no sand accumulation in the center of the electrostatic chuck, avoiding the difference between the center of the electrostatic chuck and the rest of the area. In addition, a large number of experiments have also confirmed that setting a certain offset spacing will obtain an ideal contour, while directly passing through the center of the circle will cause large fluctuations in the contour flatness.
[0013] The offset spacing is d, 1 mm ≤ d ≤ 20 mm. When the offset spacing is within this range, a perfect contour surface can be obtained, and sufficient sandblasting can be performed on the center area.
[0014] In step S1, the plane is polished by multiple progressive polishing steps to improve the polishing accuracy. In step S1, the polishing quality is improved by multiple progressive polishing steps and the polishing efficiency is improved.
[0015] In step S3, the flexible polishing device includes a flexible sheet having grooves on its surface for draining the polishing agent during the polishing process. The flexible sheet can better conform to the shape of the recessed contour, and the grooves can drain the polishing agent, thereby ensuring polishing quality. The flexible sheet also increases its bending and deformation capacity, preventing the sheet from excessively stretching during bending, which could reduce polishing quality.
[0016] The thickness of the flexible sheet is T, 1mm≤T≤3mm. Setting the thickness of the flexible sheet within this range can improve polishing quality and polishing efficiency.
[0017] During the sandblasting process, the sandblasting nozzle begins to move from the edge of the electrostatic chuck. This causes the edge of the electrostatic chuck to move across the chuck, moving from one end of the chuck to the other, forming a concave profile on the surface of the chuck. This allows the sandblasting nozzle to perform a thorough process in one pass, ensuring efficient processing.
[0018] During the sandblasting process of the electrostatic chuck, the sandblasting nozzle starts from the center area of the electrostatic chuck and moves toward the edge area. In this solution, the sandblasting nozzle starts from the center area of the electrostatic chuck and moves outward. During the processing process, due to the rotation of the electrostatic chuck, the sandblasted gravel moves toward the edge of the electrostatic chuck due to the centrifugal force on the electrostatic chuck. As the sandblasting nozzle continues to translate outward, the gravel also moves outward. The area processed by the sandblasting nozzle will not be scratched a second time by the centrifugal sand, and will always remain undisturbed. The smoothness of the area after the sandblasting nozzle passes is the smoothness of the entire electrostatic chuck after the processing.
[0019] The beneficial effects of the present invention are as follows:
[0020] (1) It can stably obtain micro-curved surface profiles that meet standards, and improve the uniformity of the product surface through sandblasting process, while eliminating the need for high-cost ultra-high precision machine tools, thereby reducing production costs;
[0021] (2) The sandblasting machine nozzle has different translation speeds in different speed control ranges, which can better adapt to the rotating electrostatic chuck and ensure that the sandblasting degree on each area of the electrostatic chuck is within a controllable range;
[0022] (3) When the sandblasting area and the center area of the electrostatic chuck are offset, this balance will be broken, and there will be no sand accumulation in the center area of the electrostatic chuck, reducing the impact of sand accumulation and avoiding the difference between the center area of the electrostatic chuck and the rest of the area;
[0023] (4) The use of a flexible polishing device can better fit the concave contour, avoid missing corners and arcs during the contour polishing of the concave contour, and improve the polishing quality;
[0024] (5) Setting the movement trajectory of the sandblasting machine nozzle to start from the center area can ensure that the sand and gravel also move outward synchronously during the continuous translation of the sandblasting machine nozzle to the outside. In this way, the area where the processing is completed will not be scratched by the centrifugal motion of the gravel for the second time, and it will always remain undisturbed, thereby improving the quality of the finished product. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 It is a flow chart of the present invention.
[0026] Figure 2 It is a structural diagram of Example 1.
[0027] Figure 3 Schematic diagram of the structure of the flexible sheet in Example 1.
[0028] Figure 4 It is a structural diagram of Example 2.
[0029] In the figure: 1 electrostatic chuck, 11 electrostatic chuck center, 2 sandblasting nozzle, 3 flexible sheet, 31 groove. DETAILED DESCRIPTION
[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0031] Example 1:
[0032] like Figure 1 As shown, a method for processing a micro-curved surface profile of a ceramic surface of an electrostatic chuck 1 includes the following steps:
[0033] S1. Using a polishing agent to plane-polish the ceramic surface of the electrostatic chuck;
[0034] S2, rotating the electrostatic chuck 1 and simultaneously moving the sandblasting nozzle 2, which is located above the electrostatic chuck 1 and moves in a direction transverse to the electrostatic chuck 1, to sandblast the surface of the electrostatic chuck 1 to form a contoured surface;
[0035] S3. Use a flexible polishing device to perform contour polishing on the contour surface processed in step S2.
[0036] In step S2, the movement path of the sandblasting nozzle 2 when sandblasting the electrostatic chuck 1 includes several speed control intervals, and the movement speed of the sandblasting nozzle 2 varies in each speed control interval;
[0037] In step S2 , there is an offset distance between the movement path of the sandblasting nozzle 2 on the electrostatic chuck 1 and the center 11 of the electrostatic chuck.
[0038] First, the surface of the electrostatic suction cup 1 is polished to obtain a plane with very good flatness, which provides a good foundation for the subsequent sandblasting. The concave contour processing at various places on the electrostatic suction cup 1 can obtain a consistent positioning reference, and the sandblasting process is used to process the concave contour, which can well maintain the uniformity of the surface. Although there will be slight differences in the sandblasting process, they can be corrected through subsequent contour polishing. The processing process is relatively gentle. Compared with the machine tool processing in the prior art, it not only saves the high cost of the processing equipment itself, but also improves the fault tolerance rate. During the sandblasting process, the electrostatic suction cup 1 is prevented from automatically rotating on the turntable, and the sandblasting machine nozzle 2 is controlled to translate across the top of the electrostatic suction cup 1. During the rotation of the disk 1, the ceramic surface of the electrostatic suction cup 1 is contoured, thereby obtaining a uniform concave contour. The precision requirements for the processing equipment are not high, and the cost of regularly replacing the processing equipment to maintain the processing precision is avoided. After the contour sandblasting is completed, the use of a flexible polishing device can better fit the concave contour, and in the process of contour polishing the concave contour, it avoids missing corners and arcs, thereby improving the polishing quality; the sandblasting machine nozzle 2 has different translation speeds in different speed control ranges, which can better adapt to the rotating electrostatic suction cup 1, ensuring that the sandblasting degree on each area of the electrostatic suction cup 1 is within a controllable range. If the sandblasting machine nozzle 2 moves at a uniform speed, due to the sandblasting The area becomes smaller as it moves towards the center, and because of the uniform speed blasting, the time it takes to blast each area is longer and longer. Although a concave contour will be formed in the middle, it cannot meet the requirement of 5μm-10μm. The speed change between the speed control intervals is stepless, ensuring a smooth transition between each speed control interval; the sandblasting machine nozzle 2 has a sandblasting range, and the "offset spacing" refers to the offset gap between the center of the sandblasting range and the center of the electrostatic suction cup 1, but the sandblasting range will still cover the center of the electrostatic suction cup 1, thereby ensuring that a complete contour surface can be processed; the rotation of the electrostatic suction cup 1 will generate centrifugal force. If the sandblasting machine nozzle 2 passes directly through the center of the circle, the sand sprayed by the sandblasting machine nozzle 2 will be The gravel is too symmetrical on the electrostatic chuck 1. When it passes through the center area, it will cause the force area balance between the gravel attached to the center 11 of the electrostatic chuck, resulting in gravel that cannot be thrown out in the center 11 of the electrostatic chuck, and then the center area cannot obtain the ideal contour. When there is an offset between the sandblasting area and the center 11 of the electrostatic chuck, this balance will be broken, and there will be no gravel accumulation in the center 11 of the electrostatic chuck, avoiding the difference between the center 11 of the electrostatic chuck and the other areas. In addition, a large number of experiments have also confirmed that setting a certain offset spacing will obtain the ideal contour, while directly passing through the center will cause large fluctuations in the contour flatness.
[0039] like Figure 2As shown, there are 100 speed control intervals, and the offset spacing d is 10 mm.
[0040] The contour processing accuracy can be controlled by controlling the speed, and there will be no machining faults on the continuous contour surface, thus ensuring the quality of the processed contour surface, reducing the difficulty of subsequent contour polishing, ensuring a perfect contour surface, and ensuring that the center area is fully sandblasted.
[0041] like Figure 3 As shown, in step S1, the plane polishing adopts multiple progressive polishing to improve the polishing accuracy in stages. In step S3, the flexible polishing device includes a flexible sheet 3, and the surface of the flexible sheet 3 is provided with grooves 31 for draining liquid during the polishing process. The thickness of the flexible sheet 3 is T, which is 3 mm.
[0042] In step S1, the polishing quality is improved and the polishing efficiency is improved through multiple progressive polishing. By setting the flexible sheet 3, it can better fit the shape of the concave contour. At the same time, the grooves set can drain the polishing agent, thereby ensuring the quality of polishing. At the same time, it can increase the bending deformation ability of the flexible sheet 3 to avoid excessive stretching of the flexible sheet 3 during the bending process, thereby reducing the polishing quality. The thickness of the flexible sheet is set at 3mm to ensure the maximization of the polishing quality and polishing efficiency.
[0043] like Figure 2 As shown, during the sandblasting process on the electrostatic chuck 1, the sandblasting nozzle 2 starts to move from the edge of the electrostatic chuck 1. As a result, the edge of the electrostatic chuck 1 starts to move, traversing the electrostatic chuck 1, thereby moving from one end of the electrostatic chuck 1 to the other end, forming a concave profile on the surface of the electrostatic chuck 1. The sandblasting nozzle 2 can perform thorough processing in one go, ensuring processing efficiency.
[0044] In this embodiment, the processing method of the micro-curved surface contour of the ceramic surface of the electrostatic chuck 1 is as follows: If the surface of the electrostatic chuck 1 wants to obtain a contour morphology with very good precision, a plane with very good flatness must be processed first. In this embodiment, 10μm, 5μm, 3μm, and 1μm diamond particles are used as polishing agents, and multiple progressive polishings are performed to increase the polishing time from the original 1h to 3h. At the same time, water and polishing powder are mixed in a ratio of 100:10 as a polishing liquid to improve the polishing quality. After the surface processing of the electrostatic chuck 1 is completed, the electrostatic chuck 1 is sandblasted. The electrostatic chuck 1 is placed on a rotating table for rotation, and the sandblasting machine is started at the same time. The machine nozzle 2 performs linear motion above the electrostatic suction cup 1. There is a 10mm offset between the linear motion path and the center of the electrostatic suction cup 1, and the linear path motion is divided into 100 speed control intervals to adaptively limit the speed of the electrostatic suction cup 1 in different areas. Then, it moves from one end of the electrostatic suction cup 1 to the other end to complete the sandblasting operation and form a concave contour. Then, a flexible polishing device is used to polish the contour. As the contour surface morphology changes within a certain range, various parts of the contour surface can be effectively polished, thereby obtaining a roughness that meets the requirements. The final contour surface roughness is below Ra0.4, which meets the surface roughness requirements of the electrostatic suction cup 1.
[0045] Example 2:
[0046] like Figure 4 As shown, unlike Example 1, in this embodiment, the sandblasting nozzle 2 moves from the center area of the electrostatic chuck 1 toward the edge area during the sandblasting process of the electrostatic chuck 1. In this embodiment, the sandblasting nozzle 2 moves outward from the center area of the electrostatic chuck 1. During the processing, due to the rotation of the electrostatic chuck 1, the sandblasted gravel moves toward the edge of the electrostatic chuck 1 due to the centrifugal force on the electrostatic chuck 1. As the sandblasting nozzle 2 continues to translate outward, the gravel also moves outward. The area processed by the sandblasting nozzle 2 will not be scratched again by the centrifugal sand and remains undisturbed. The smoothness of the area after the sandblasting nozzle 2 passes is the same as the smoothness of the entire electrostatic chuck 1 after the processing.
Claims
1. A method for processing a micro-curved surface profile of an electrostatic chuck ceramic surface, characterized in that: The following steps are included: S1, using a polishing agent to plane-polish the ceramic surface of the electrostatic chuck (1); S2, rotating the electrostatic chuck (1) and simultaneously moving the sandblasting machine nozzle (2), wherein the sandblasting machine nozzle (2) is located above the electrostatic chuck (1) and moves in a direction transverse to the electrostatic chuck (1), performing surface sandblasting on the electrostatic chuck (1) to form a contour surface, and an offset distance exists between the movement path of the sandblasting machine nozzle (2) on the electrostatic chuck (1) and the center (11) of the electrostatic chuck; S3. Use a flexible polishing device to perform contour polishing on the contour surface processed in step S2.
2. The method for machining a micro-curved surface profile of an electrostatic chuck ceramic according to claim 1, characterized in that: In step S2, the movement path of the sandblasting machine nozzle (2) when sandblasting the electrostatic suction cup (1) includes a plurality of speed control intervals, and the movement speed of the sandblasting machine nozzle (2) varies in each speed control interval.
3. The method for machining a micro-curved surface profile of an electrostatic chuck ceramic according to claim 2, characterized in that: The number of speed control intervals is x, 80≤x≤120.
4. The method for machining a micro-curved surface profile of an electrostatic chuck ceramic according to claim 1, characterized in that: The offset spacing is d, 1mm≤d≤20mm.
5. The method for machining a micro-curved surface profile of an electrostatic chuck ceramic according to claim 1, characterized in that: In step S1 , the plane is polished using multiple progressive polishing steps to improve the polishing accuracy step by step.
6. The method for machining a micro-curved surface profile of an electrostatic chuck ceramic according to claim 1, characterized in that: In step S3, the flexible polishing device comprises a flexible sheet (3), wherein a surface of the flexible sheet (3) is provided with grooves (31) for draining liquid during the polishing process.
7. The method for machining a micro-curved surface profile of an electrostatic chuck ceramic according to claim 6, characterized in that: The thickness of the flexible sheet (3) is T, 1mm≤T≤3mm.
8. A method for machining a micro-curved surface profile of an electrostatic chuck ceramic according to any one of claims 1 to 7, characterized in that: The sandblasting nozzle (2) starts to move from the edge of the electrostatic chuck (1) during the sandblasting process of the electrostatic chuck (1).
9. A method for machining a micro-curved surface profile of an electrostatic chuck ceramic according to any one of claims 1 to 7, characterized in that: During the sandblasting process on the electrostatic chuck (1), the sandblasting machine nozzle (2) starts from the central area of the electrostatic chuck (1) and moves toward the edge area.