A method for polishing a large-size quartz substrate
Patent Information
- Application Number
- CN202611447858.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-17
- Publication Date
- 2026-11-03
AI Technical Summary
Existing single-sided grinding methods for large-size quartz substrates suffer from problems such as low processing efficiency, lack of reliable positioning reference during flipping and secondary clamping, difficulty in ensuring the grinding slurry reaches the center area of the substrate, excessive grinding at the four corners and insufficient grinding in the center area, resulting in difficulty in achieving the preset parallelism accuracy.
The system employs a lower fixed plate with magnetic adsorption function and an upper fixed plate with a grinding layer. Combined with a frame fixture and a central liquid supply channel, a multi-stage grinding process can be achieved by adjusting the eccentric distance and the left and right swing distance. This ensures that the grinding pressure is controllable and the grinding liquid is evenly distributed. In addition, magnetic fixation and lateral limiting eliminate the interference of the pressure plate covering on the grinding process.
It significantly improves grinding efficiency, shortens processing time, ensures that the parallelism of the two sides of the substrate reaches within 30μm, reduces the difficulty and cost of raw material procurement, and solves the defects in the existing technology.
Smart Images
Figure CN123025216A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of precision grinding technology, and in particular to a grinding method for large-size quartz substrates. Background Technology
[0002] Large-size quartz mask blank substrates (diagonal dimensions 800mm to 1420mm) have strict requirements for flatness, thickness difference, and parallelism, and are key basic materials for photolithography processes in flat panel displays, semiconductors, and other fields. Due to the scarcity of double-sided grinding and polishing equipment suitable for ultra-large quartz substrates, existing technologies typically employ a single-sided grinding method to process quartz blank substrates: one side of the quartz blank substrate is placed flat on a rotating grinding disk, while the other side is pressed down from above by a pressure plate approximately 20mm thick. The pressure plate is linked to the grinding disk via an eccentric support, and the quartz blank substrate is ground using approximately its own weight. This method has the following two drawbacks: First, the self-weight pressure method cannot actively adjust the grinding pressure, resulting in low processing efficiency. Grinding a single substrate usually takes one to two days, and there is a lack of reliable positioning reference when flipping and clamping the substrate a second time, leading to low reset accuracy. Second, the pressure plate covers the upper surface of the substrate, making it difficult for the grinding slurry to fully reach the central area of the substrate. The grinding rate is inconsistent between the center of the disk and the outer edge of the disk, and the four corners of the quartz blank substrate are prone to over-grinding (corner collapse), while the grinding amount in the central area is insufficient. When flipping and grinding the second side, it is difficult to ensure the parallelism of the two sides. Under the current process conditions, it is difficult to stably achieve the requirement of within 30μm for parallelism. Summary of the Invention
[0003] The purpose of this invention is to solve the following problems existing in the background art: the single-sided grinding method uses a pressure plate to press the quartz blank substrate and applies pressure by its own weight for grinding, resulting in extremely low processing efficiency, lack of reliable positioning reference when flipping and clamping, and the pressure plate covering the upper surface of the substrate makes it difficult for the grinding liquid to fully reach the center area of the substrate, resulting in excessive grinding at the four corners of the quartz blank substrate and insufficient grinding in the center area, and the parallelism of the two sides after flipping and grinding is difficult to stably reach the preset accuracy.
[0004] To achieve the above objectives, the present invention provides a grinding process for large-size quartz substrates, comprising the following steps: S1 provides a lower plate with magnetic adsorption function, and an upper plate with a grinding layer on the working surface and a central liquid supply channel. S2, place the frame fixture on the working surface of the lower platen. The frame fixture surrounds the quartz blank substrate and forms a lateral limit on the quartz blank substrate. The thickness of the frame fixture is less than the thickness of the quartz blank substrate. S3, place the quartz blank substrate with its concave side facing down into the frame fixture, activate the magnetic attraction of the lower fixed plate, and adsorb and fix the quartz blank substrate onto the working surface of the lower fixed plate. S4. According to the size and thickness of the quartz blank substrate, adjust the eccentric distance between the upper fixed plate and the lower fixed plate and the left and right swing distance of the upper fixed plate. Supply polishing liquid to the upper surface of the quartz blank substrate through the central liquid supply channel. Polish the convex surface of the quartz blank substrate according to the multi-segment polishing program. Set different polishing pressure and polishing speed for each segment until the convex surface is fully polished. S5. After cleaning the working surface of the lower platen, flip the quartz blank substrate over and fix it with the concave side facing up in accordance with S3. Then set the program parameters in accordance with S4 to grind the concave side of the quartz blank substrate until the concave side is completely ground and flattened to meet the predetermined flatness requirements. S6. After cleaning the working surface of the lower platen, flip the quartz blank substrate over again and fix it with the convex side facing up in accordance with the method of S3. Then set the program parameters in accordance with the method of S4 to grind the convex side of the quartz blank substrate until the flatness and thickness of the convex side meet the specifications.
[0005] Furthermore, prior to S3, the process includes: distinguishing the concave and convex surfaces of the quartz blank substrate, measuring and recording the thickness of the four corners and four sides of the quartz blank substrate, and determining the grinding pressure and grinding speed parameters for each grinding process based on the measurement data.
[0006] Furthermore, the frame fixture is made of alumina material, and the thickness of the frame fixture is 1 mm to 2 mm less than the thickness of the quartz blank substrate.
[0007] Furthermore, the sleeve frame fixture is provided with an inner groove, and the fixing member is connected to the sleeve frame fixture by means of a boss engaging the inner groove. The fixing member is magnetically engaged with the lower fixed plate to limit the displacement of the sleeve frame fixture relative to the lower fixed plate.
[0008] Furthermore, the central liquid supply channel includes multiple rings of liquid supply holes distributed with different radii along the radial direction of the upper fixed plate, with each ring of liquid supply holes distributed at equal intervals along the corresponding circumference.
[0009] Furthermore, before S4, the process also includes: trimming the grinding layer of the upper plate so that the flatness of the working surface of the grinding layer is within 0.015mm.
[0010] Furthermore, when determining the parameters of each grinding program segment, the expected flatness after grinding is calculated according to the flatness of the lower fixed plate, the flatness of the upper fixed plate, the peak value of the lower fixed plate end jump, the ratio of the diameter of the upper fixed plate to the diameter of the lower fixed plate, the ratio of the left and right swing distance of the upper fixed plate to the length of the workpiece diagonal, and the flatness of the workpiece before grinding, so as to guide the setting of the grinding pressure and grinding speed parameters of each segment.
[0011] Furthermore, the expression for the flatness prediction model is as follows:
[0012] in, This represents the predicted flatness data of the substrate after polishing; positive numbers indicate a convex surface, and negative numbers indicate a concave surface. This indicates the flatness of the lower platen, with a negative value for the center low. This indicates the flatness of the upper plate; a convex shape represents a positive value, and a concave shape represents a negative value. Indicates the peak value at the lower fixed plate end; Indicates the diameter of the upper plate (; Indicates the diameter of the lower plate; Indicates the distance the upper body swings left and right; Indicates the flatness of the workpiece length (along the swing direction); This indicates the flatness of the workpiece before grinding, with convex surfaces being positive. This indicates the amount removed by grinding on one side.
[0013] Furthermore, the diagonal dimension of the quartz blank substrate is 800mm to 1420mm.
[0014] Furthermore, the lower plate is composed of a marble plate and a stainless steel layer stacked together, and the diameter of the lower plate is 1800mm.
[0015] The above-described solution of the present invention has the following beneficial effects: The grinding pressure is actively controllable by adjusting the upper fixed plate's spin pressing. The grinding trajectory coverage is controlled by adjusting the eccentric distance between the upper and lower fixed plates and the left and right swing distance of the upper fixed plate. A multi-stage grinding program with different pressures and speeds is used to grind and smooth the concave and convex sides of the substrate step by step. Compared with the existing self-weight pressure application method, the grinding pressure can be flexibly adjusted according to processing requirements, and the grinding efficiency is significantly improved. The time required to grind a large-size quartz blank substrate is greatly shortened. At the same time, the flatness requirement of the quartz blank substrate raw material can be relaxed to more than 300μm, reducing the difficulty and cost of raw material procurement.
[0016] By modifying the lower fixing plate into a magnetically adsorbed fixing plate, and using a frame fixture to implement lateral positioning of the quartz blank substrate on all four sides, the substrate is stably adsorbed and fixed on the working surface of the lower fixing plate without the pressure plate covering it, and the upper surface of the substrate is completely open. This fixing method fundamentally eliminates the interference of the existing pressure plate covering on the distribution of polishing slurry and the uniformity of polishing. At the same time, the magnetic fixing method has high positioning repeatability, and the substrate can be reliably fixed in the same position during the second clamping after flipping, effectively solving the problem of low flipping and resetting accuracy of the existing method.
[0017] By changing the liquid supply method from side-feeding to liquid supply through multiple equally spaced supply holes in the center of the upper fixed plate, the polishing slurry is evenly diffused from the center of the upper fixed plate to the entire area of the substrate under the action of centrifugal force. This eliminates the defect of insufficient polishing slurry supply in the center area of the lower plate in the existing side-feeding method, making the polishing rate of each area of the substrate more consistent. It effectively suppresses the problems of excessive polishing (corner collapse) at the four corners and insufficient polishing in the center area, laying the process foundation for achieving a stable parallelism of less than 30μm between the two sides after flipping.
[0018] Other beneficial effects of the present invention will be described in detail in the following detailed description section. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the grinding system of the present invention; Figure 2 This is a top view of the upper fixing plate of the present invention; Figure 3 This is a flowchart of the grinding process of the present invention.
[0020] [Explanation of Labels in the Attached Image] 1-Lower plate; 2-Frame tooling; 3-Fixed component; 4-Upper plate; 41-Central liquid supply channel; 42-Liquid supply hole; 5-Quartz blank substrate. Detailed Implementation
[0021] To make the technical problems, solutions, and advantages of this invention clearer, a detailed description will be provided below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Furthermore, the technical features involved in the different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.
[0022] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0023] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a locking connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0024] Reference Figure 1 This invention provides a grinding method for large-size quartz substrates. The grinding system used in this method includes a lower fixed plate 1, a frame fixture 2, a fixing component 3, and an upper fixed plate 4. The lower fixed plate 1 has a magnetic adsorption function, and its working surface is horizontally set, enabling it to magnetically attract and fix the workpiece placed on it. The upper fixed plate 4 is located directly above the lower fixed plate 1, and its working surface is coated with a grinding layer. The grinding layer contacts the upper surface of the quartz blank substrate 5 and applies grinding pressure. The upper fixed plate 4 achieves active control of the grinding pressure through spinning adjustment, and the eccentric distance between the upper fixed plate 4 and the lower fixed plate 1, as well as the left and right swing distance of the upper fixed plate 4, can be adjusted according to processing requirements, thereby controlling the coverage and uniformity of the grinding trajectory.
[0025] At the same time, such as Figure 2 As shown, the upper fixed plate 4 is provided with a central liquid supply channel 41, which includes multiple rings of liquid supply holes 42 distributed radially along the upper fixed plate 4 at different radii. Each ring of liquid supply holes 42 is evenly spaced along the corresponding circumference. The polishing slurry is supplied outward from the central area of the upper fixed plate 4 through each ring of liquid supply holes 42, and under the action of centrifugal force, it is evenly diffused to the entire area of the upper surface of the quartz blank substrate 5, eliminating the problem of insufficient polishing slurry supply in the central area of the plate under the side-supply method, and making the polishing rate of each area of the substrate tend to be uniform.
[0026] The frame fixture 2 is placed on the working surface of the lower fixed plate 1. The frame fixture 2 surrounds the quartz blank substrate 5, forming a lateral limit on the quartz blank substrate 5 to prevent lateral displacement of the substrate during grinding. The thickness of the frame fixture 2 is less than the thickness of the quartz blank substrate 5, so that the upper surface of the substrate is higher than the upper surface of the frame fixture 2, thereby ensuring that the grinding layer of the upper fixed plate 4 can fully contact the upper surface of the substrate for effective grinding.
[0027] The fixing member 3 is disposed between the sleeve frame fixture 2 and the lower fixed plate 1. The sleeve frame fixture 2 is provided with an inner groove. The fixing member 3 is connected to the sleeve frame fixture 2 by means of a boss engaging the inner groove. The fixing member 3 is also magnetically fixed to the lower fixed plate 1 by magnetic force, thereby reliably positioning the sleeve frame fixture 2 in the center of the working surface of the lower fixed plate 1, limiting the displacement of the sleeve frame fixture 2 relative to the lower fixed plate 1, and preventing the sleeve frame fixture 2 from shifting due to force during the grinding process.
[0028] Based on this grinding system, and simultaneously Figure 3 As shown, the grinding process for the large-size quartz substrate described above includes the following steps: First, before grinding, the grinding layer on the upper platen 4 is trimmed with an oilstone to ensure that the flatness of the working surface of the grinding layer is within 0.015mm. Since the flatness of the working surface of the grinding layer directly affects the flatness of the substrate after grinding, trimming the grinding layer to within 0.015mm ensures uniform contact between the grinding layer and the upper surface of the substrate, avoiding local over-grinding or under-grinding of the substrate due to local protrusions or depressions in the grinding layer.
[0029] Secondly, the concave and convex surfaces of the quartz blank substrate 5 are distinguished, and the thickness of the four corners and four sides of the quartz blank substrate 5 is measured and recorded. By pre-measuring the thickness data of each part of the substrate, the pressure and speed parameters in each stage of the grinding process can be set in a targeted manner, so that the grinding amount distribution matches the initial morphology of the substrate, thereby improving the grinding accuracy and processing efficiency.
[0030] Subsequently, the sleeve fixture 2 is placed centered on the working surface of the lower fixed plate 1. The protrusion of the fixing member 3 is inserted into the inner groove of the sleeve fixture 2, and the fixing member 3 is fixed to the lower fixed plate 1 by magnetic force, so that the sleeve fixture 2 is positioned in the center of the working surface of the lower fixed plate 1. The quartz blank substrate 5 is placed in the sleeve fixture 2 with its concave side facing down, and the magnetic attraction of the lower fixed plate 1 is activated. The quartz blank substrate 5 is attracted and fixed to the working surface of the lower fixed plate 1. At this time, the upper surface of the substrate is completely open, without the pressure plate covering or obstructing it, creating conditions for the uniform distribution of the polishing slurry.
[0031] Then, based on the size and thickness of the quartz blank substrate 5, the eccentric distance between the upper fixed plate 4 and the lower fixed plate 1, as well as the left-right swing distance of the upper fixed plate 4, are adjusted. Grinding fluid is supplied to the upper surface of the quartz blank substrate 5 through the central liquid supply channel 41. The convex surface of the quartz blank substrate 5 is ground according to a multi-stage grinding program, with different grinding pressures and speeds set for each stage, until the convex surface is fully ground. By adjusting the eccentric distance and the left-right swing distance, the movement trajectory coverage of the grinding layer of the upper fixed plate 4 on the upper surface of the substrate can be controlled, ensuring that the grinding trajectory uniformly covers the entire area of the substrate. The multi-stage grinding program with different pressures and speeds balances the grinding efficiency and precision at different stages, effectively avoiding the problem of localized over-grinding under a single parameter.
[0032] After the convex surface is ground to the desired level, clean the working surface of the lower fixed plate 1, flip the quartz blank substrate 5 over, and fix the substrate to the working surface of the lower fixed plate 1 with the concave side facing up, using the aforementioned fixing method. Then, set the eccentric distance, left and right swing distance, and multi-segment grinding program parameters as described above, and grind the concave surface of the quartz blank substrate 5 until the concave surface is completely ground and smoothed to the predetermined flatness requirement.
[0033] After concave grinding is completed, the working surface of the lower fixing plate 1 is cleaned again. The quartz blank substrate 5 is then flipped over again, and the substrate is adsorbed and fixed onto the working surface of the lower fixing plate 1 with the convex side facing upwards, as described above. The program parameters are then set as described above to grind the convex surface of the quartz blank substrate 5 until the flatness and thickness of the convex surface meet the specifications. After the above three-step grinding process, the flatness of both sides of the quartz blank substrate 5 reaches within 30μm, and the parallelism between the two sides reaches within 30μm.
[0034] In one embodiment, the frame fixture 2 is made of alumina material, and its thickness is 1 mm to 2 mm less than the thickness of the quartz blank substrate 5. Alumina material has good wear resistance and will not scratch the sides of the quartz blank substrate 5 during grinding, and the frame fixture 2 itself does not participate in the grinding process. The 1 mm to 2 mm thinner thickness of the frame fixture 2 ensures that the upper surface of the substrate is 1 mm to 2 mm higher than the upper surface of the frame fixture 2, allowing the grinding layer of the upper platen 4 to fully contact the upper surface of the substrate for effective grinding. Simultaneously, the frame fixture 2 provides reliable lateral restraint to the substrate.
[0035] In another implementation, when determining the parameters of each grinding stage, a flatness prediction model can be used to estimate the flatness after grinding, thereby guiding the setting of grinding pressure and grinding speed parameters for each stage. The expression for this flatness prediction model is as follows:
[0036] in, This represents the predicted flatness data of the substrate after polishing; positive numbers indicate a convex surface, and negative numbers indicate a concave surface. This indicates the flatness of the lower fixed plate 1 (in mm), with a negative value for the center low. The flatness of the upper plate is indicated by mm; convexity is a positive value, and concaveness is a negative value. Indicates the peak value of the lower fixed plate at end 1 (unit: mm); This indicates the diameter of the upper fixed plate 4 (unit: mm); Indicates the diameter of the lower plate 1 (unit: mm); Indicates the distance the upper plate swings left and right (unit: mm); Indicates the flatness of the workpiece length (along the swing direction, in mm); This indicates the flatness of the workpiece before grinding (unit: mm), with convex surfaces being positive. This indicates the amount of material removed by grinding on one side (in mm).
[0037] In the above model, The item reflects the direct influence of the shapes of the lower fixed plate 1 and the upper fixed plate 4 on the flatness of the workpiece: the center of the lower fixed plate 1 is lower ( (Negative values) easily cause the workpiece to form a convex surface, and the upper fixed plate has 4 convexities ( (If the value is positive, it will easily cause the workpiece to form a concave surface, so the two have opposite signs.) The factor reflecting the effect of end jump on the grinding flatness is the ratio of this coefficient to the covering capacity of the upper fixed plate 4. and swing stroke ratio Correlation indicates the average effect of motion. The term reflects the exponential decay of initial flatness as the amount of material removed increases.
[0038] By incorporating key parameters such as the shape error of the lower fixed plate 1, the shape error of the upper fixed plate 4, the effect of end runout, the coverage ratio of the upper and lower fixed plates 1, and the initial workpiece flatness into the model calculation, the processing results can be predicted before grinding. This allows for the scientific and reasonable setting of grinding parameters for each section, reducing excessive or insufficient grinding caused by improper parameter settings, and improving processing accuracy and first-pass success rate.
[0039] Compared with existing gravity-based single-sided grinding methods, the grinding method provided in this embodiment has the following technical advantages: The magnetic attraction of the lower fixed plate 1 directly adsorbs and fixes the quartz blank substrate 5 onto the working surface, and the upper surface of the substrate is completely open without the cover of the pressure plate, which fundamentally eliminates the interference of the existing pressure plate cover on the distribution of grinding fluid and the uniformity of grinding; The central liquid supply channel 41 supplies the grinding fluid evenly from the central area of the upper fixed plate 4 outward, and under the action of centrifugal force, the grinding fluid covers the entire area of the substrate, effectively suppressing the defects of excessive grinding at the four corners and insufficient grinding in the central area; The spinning adjustment of the upper fixed plate 4 makes the grinding pressure actively controllable, significantly improving the grinding efficiency and greatly shortening the time required to grind a large-size quartz blank substrate 5; At the same time, the flatness requirement of the raw material of the quartz blank substrate 5 can be relaxed to more than 300μm, reducing the difficulty and cost of raw material procurement.
[0040] Understandably, without changing the core grinding mechanism mentioned above, the material of the frame tooling 2 is not limited to alumina. Other non-metallic materials with good wear resistance and that do not participate in grinding can also be used, as long as they can form effective lateral limiting constraints around the quartz blank substrate 5.
[0041] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0042] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.
Claims
1. A grinding process for large-size quartz substrates, characterized in that, Includes the following steps: S1 provides a lower plate with magnetic adsorption function, and an upper plate with a grinding layer on the working surface and a central liquid supply channel. S2, place the frame fixture on the working surface of the lower platen. The frame fixture surrounds the quartz blank substrate and forms a lateral limit on the quartz blank substrate. The thickness of the frame fixture is less than the thickness of the quartz blank substrate. S3, place the quartz blank substrate with its concave side facing down into the frame fixture, activate the magnetic attraction of the lower fixed plate, and adsorb and fix the quartz blank substrate onto the working surface of the lower fixed plate. S4. According to the size and thickness of the quartz blank substrate, adjust the eccentric distance between the upper fixed plate and the lower fixed plate and the left and right swing distance of the upper fixed plate. Supply polishing liquid to the upper surface of the quartz blank substrate through the central liquid supply channel. Polish the convex surface of the quartz blank substrate according to the multi-segment polishing program. Set different polishing pressure and polishing speed for each segment until the convex surface is fully polished. S5. After cleaning the working surface of the lower platen, flip the quartz blank substrate over and fix it with the concave side facing up in accordance with S3. Then set the program parameters in accordance with S4 to grind the concave side of the quartz blank substrate until the concave side is completely ground and flattened to meet the predetermined flatness requirements. S6. After cleaning the working surface of the lower platen, flip the quartz blank substrate over again and fix it with the convex side facing up in accordance with the method of S3. Then set the program parameters in accordance with the method of S4 to grind the convex side of the quartz blank substrate until the flatness and thickness of the convex side meet the specifications.
2. The grinding process for a large-size quartz substrate according to claim 1, characterized in that, Before S3, the process also includes: distinguishing the concave and convex surfaces of the quartz blank substrate, measuring and recording the thickness of the four corners and four sides of the quartz blank substrate, and determining the grinding pressure and grinding speed parameters of each grinding process based on the measurement data.
3. The grinding process for a large-size quartz substrate according to claim 1, characterized in that, The frame fixture is made of alumina material, and the thickness of the frame fixture is 1 mm to 2 mm less than the thickness of the quartz blank substrate.
4. The grinding method for large-size quartz substrates according to claim 1, characterized in that, The sleeve frame fixture is provided with an inner groove, and the fixing member is connected to the sleeve frame fixture by means of a boss engaging the inner groove. The fixing member is magnetically engaged with the lower fixed plate to limit the displacement of the sleeve frame fixture relative to the lower fixed plate.
5. The grinding process for a large-size quartz substrate according to claim 1, characterized in that, The central liquid supply channel includes multiple rings of liquid supply holes distributed with different radii along the radial direction of the upper fixed plate, with each ring of liquid supply holes distributed at equal intervals along the corresponding circumference.
6. The grinding process for a large-size quartz substrate according to claim 1, characterized in that, Before S4, the process also includes: trimming the grinding layer of the upper plate so that the flatness of the working surface of the grinding layer is within 0.015mm.
7. The grinding process for a large-size quartz substrate according to claim 1, characterized in that, When determining the parameters of each grinding program segment, the expected flatness after grinding is calculated according to the flatness of the lower fixed plate, the flatness of the upper fixed plate, the peak value of the lower fixed plate end jump, the ratio of the diameter of the upper fixed plate to the diameter of the lower fixed plate, the ratio of the left and right swing distance of the upper fixed plate to the length of the workpiece diagonal, and the flatness of the workpiece before grinding, so as to guide the setting of grinding pressure and grinding speed parameters for each segment.
8. The grinding process for a large-size quartz substrate according to claim 7, characterized in that, The expression for the flatness prediction model is as follows: in, This represents the predicted flatness data of the substrate after polishing; positive numbers indicate a convex surface, and negative numbers indicate a concave surface. This indicates the flatness of the lower platen, with a negative value for the center low. This indicates the flatness of the upper plate; a convex shape represents a positive value, and a concave shape represents a negative value. Indicates the peak value at the lower fixed end; Indicates the diameter of the upper plate (; Indicates the diameter of the lower plate; Indicates the distance the upper body swings left and right; Indicates the flatness of the workpiece length (along the swing direction); This indicates the flatness of the workpiece before grinding, with convex surfaces being positive. This indicates the amount removed by grinding on one side.
9. The grinding process for a large-size quartz substrate according to claim 1, characterized in that, The diagonal dimension of the quartz blank substrate is 800mm to 1420mm.
10. The grinding process for a large-size quartz substrate according to claim 1, characterized in that, The lower plate is composed of a marble plate and a stainless steel layer, and the diameter of the lower plate is 1800mm.