Method for controlling bending degree of silicon wafer through thinning

Abstract

The invention relates to a method for controlling the bending degree of a silicon wafer through thinning, which is used for analyzing substrates and epitaxy with different epitaxy specifications and determining the Bow optimization trend of the substrates, namely, the epitaxy changes backwards in the positive direction or the negative direction. By selecting the thinning machine table and the thinning grinding wheel, the front face and the back face are thinned respectively, and geometric parameters of the silicon wafers can be accurately adjusted in batches. It is ensured that the influence or change trend of a subsequent film forming or thermal resume process on the Bow value meets the expectation, and deterioration of geometric parameters is reduced. In addition, Bow adjustment of a single wafer can be achieved, the bending degree of the adjusted silicon wafer is accurately controlled by adjusting machining parameters of thinning equipment, then the bending degree is matched with epitaxial machining conditions, and the epitaxial wafer is made to be qualified or meet preset requirements.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicon wafer processing, in particular to a double-sided differential thinning method for precise regulation of the bow value of a wafer after slicing, which is especially suitable for heavily doped boron substrate wafers of 28nm and above processes, can solve the technical problem of mismatch between the wafer and the subsequent epitaxial process, and belongs to the technical field of semiconductor manufacturing. BACKGROUND

[0002] With the continuous development of the integrated circuit industry, the quality requirements of silicon wafers are also increasing, especially in 28nm Logic and above processes, the geometric parameters such as the bow of the silicon wafer directly affect the quality and reliability of the final chip. However, in the existing silicon wafer processing technology, the bow of the wafer after slicing is basically fixed, and there is a lack of effective subsequent adjustment means. The amplification effect of the thermal history process in the epitaxial process on the bow value, especially the mismatch between the substrate bow and the change trend after epitaxy in the thick layer epitaxy scenario required by high-power devices, can easily cause the geometric parameters of the epitaxial product to deteriorate, which can cause local exposure to be misaligned during the subsequent photolithography process, thereby affecting the final parameter failure of the product and causing yield loss. The geometric parameters of the silicon wafer are mainly affected by the slicing of the wafer, and the geometric parameters of the wafer after slicing are not uniform, and the bow of the wafer is quite different between different slicing machines or different segments of the ingot.

[0003] The current processing method cannot effectively control the geometric parameters of the silicon wafer, and it is also difficult to match the geometric parameter changes of the subsequent film formation or thermal history. There is no effective means to correct the substrate wafer bow in the subsequent double-sided polishing or single wafer polishing process to accurately control the bow within the ideal range, which can easily cause the epitaxial wafer to be scrapped. In view of the problems of bow value deterioration after epitaxy and poor adaptability of the wafer to the epitaxial process, the control line of the geometric parameters of the substrate wafer is often tightened on one side, which seriously restricts the stable production of high-end wafers, and there is an urgent need for a method that can accurately and flexibly regulate the bow value of the wafer after slicing. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a method for controlling the bow of a silicon wafer by thinning, which solves the problem of large bow value fluctuation of different slicing machines in different periods processing different Lots after slicing and mismatch with the subsequent epitaxial process in the prior art. The bow value of the silicon wafer after slicing is accurately controlled by double-sided differential thinning, the bow value of the silicon wafer after slicing is accurately corrected, the geometric parameters of the substrate wafer are matched with the change trend of the bow of the epitaxial process, and the wafer scrap rate is reduced. The present application does not need to add special equipment, can adapt to existing thinning machines and measuring equipment, and reduces the cost of line transformation.

[0005] The technical solution adopted by the present application to solve its technical problem is: a method for controlling the bow of a silicon wafer by thinning, comprising the following operation steps:

[0006] The historical data of the wafer bow and the substrate wafer bow of the same mass production epitaxial wafer are analyzed, the bow processing target range of the substrate wafer is set through the change trend of the bow after epitaxy, and the bow processing target of the substrate wafer is opposite to the change trend of the bow after epitaxy;

[0007] S1, cutting treatment is performed on the silicon wafer to obtain a cut silicon wafer;

[0008] S2, a first silicon wafer is taken out for trial processing and thinning, specifically including:

[0009] S21, the cut silicon wafer is fixed on the processing machine A of the thinning device through vacuum adsorption, the front surface of the first silicon wafer is thinned by the thinning device, the topography of the vacuum chuck table of the thinning device is adjusted according to the bow processing target of the substrate wafer, and the state of the bearing surface of the vacuum chuck table will affect the bow of the thinned silicon wafer in the wafer thinning process. The side support part pressure at the bottom edge of the vacuum chuck table is adjusted by the chuck edge pressure adjustment device at the bottom of the thinning equipment, so as to change the topography (adjustment value) of the vacuum chuck table. As shown in Figure 3 , the topography is controlled by the edge air pressure of the vacuum chuck table. It can be known from experiments that increasing the edge air pressure obtains topography 1, processing the front surface of the silicon wafer, and the bow of the silicon wafer changes in the positive direction. Reducing the edge air pressure obtains topography 3, processing the front surface of the silicon wafer, and the bow of the silicon wafer changes in the negative direction;

[0010] S22, the back surface of the same silicon wafer is fixed on the processing machine B of the thinning device through vacuum adsorption, the back surface of the silicon wafer is thinned by the thinning device, and the topography and rules of the vacuum chuck table are adjusted. The front surface and the back surface are thinned in a manner of mutual cooperation and mutual enhancement, so that the bow value, i.e. the bow of the silicon wafer, can be accurately corrected towards the preset negative target value during the thinning process;

[0011] S23, the first silicon wafer is grinded and processed by the thinning device to obtain a processed first silicon wafer, and a topography of the processed first silicon wafer is obtained. The geometric parameters of the trial-processed silicon wafer are measured, the geometric parameters include bow and thickness map, the geometric parameters of the surface of the silicon wafer are obtained, the geometric parameters are used to indicate the micro-topography characteristics of the surface of the silicon wafer, the topography is a 2D topography or a 3D topography, a machine adjustment judgment scheme is made, and the processing parameters of the thinning device are adjusted. That is, in the case that the micro-topography characteristics indicated by the topography parameters are unqualified or do not meet the preset requirements, the micro-topography characteristics of the silicon wafer processed by the adjusted thinning device are accurately adjusted, so as to be qualified or meet the preset requirements;

[0012] S24, by the topography control, test and analysis of the front and back, the topography of the vacuum chuck and the bending degree change trend of the silicon wafer are combined, and the bending degree is accurately controlled; if the bending degree does not reach the target value after adjusting the thinning parameter, the vacuum chuck of the thinning equipment is replaced, and the steps of S21-S23 are repeated until the microtopography parameters of the trial processing silicon wafer meet the preset requirements, that is, the desired bending degree value is reached;

[0013] S3, a new silicon wafer is taken for conventional thinning processing, the bending degree value of the thinned silicon wafer is measured, and the conventional thinning process is compared with the above new processing process;

[0014] S4, the silicon wafer of the conventional thinning process and the silicon wafer of the new processing process are subjected to epitaxial growth, and the geometric parameters of the epitaxial wafer are measured and analyzed after epitaxial growth.

[0015] As a supplement to the technical solution of the application, in S1, the cutting process adopts a wire cutting process, the cutting speed is 0.5-1.5mm / s, and the cutting precision is controlled within ±0.01mm.

[0016] As a supplement to the technical solution of the application, the first grinding wheel of the thinning equipment A and the second grinding wheel of the thinning equipment B are both diamond grinding wheels with a particle size of 800-1200 mesh and a grinding speed of 1000-1500r / min.

[0017] As a supplement to the technical solution of the application, the bending degree value is measured by a white light interferometer.

[0018] Beneficial effects: the application relates to a method for controlling the bending degree of a silicon wafer by thinning, the thinning control method of the application effectively adjusts the Bow value of the sliced silicon wafer; the Bow optimization trend of the substrate is determined by analyzing different epitaxial specifications of the substrate and the epitaxial, that is, the substrate changes to a positive direction or a negative direction after epitaxial; by selecting a thinning machine and a thinning grinding wheel, the front and back surfaces are thinned, the geometric parameters of the silicon wafer can be accurately and batch-adjusted; the influence or change trend of the Bow value on the subsequent film forming or thermal history process meets the expectation, and the deterioration of the geometric parameters is reduced; and single-piece Bow adjustment can be realized, the processing parameters of the thinning equipment are adjusted, the bending degree of the adjusted silicon wafer is accurately controlled, and then the epitaxial processing conditions are matched, so that the epitaxial wafer is qualified or meets the preset requirements. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a step diagram of the application;

[0020] Figure 2 is a Bow change trend diagram of different epitaxial specifications of a heavily doped boron substrate silicon wafer according to the application;

[0021] Figure 3 is a schematic diagram of the appearance adjustment of the vacuum chuck of the present application;

[0022] Figure 4 is a schematic diagram of the thinning and the change of the bending degree of the substrate sheet, which tends to change to the negative direction;

[0023] Figure 5 is a schematic diagram of the thinning and the change of the bending degree of the substrate sheet, which tends to change to the positive direction. DETAILED DESCRIPTION

[0024] The present application will be further described below in connection with specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not used to limit the scope of the present application. Furthermore, it should be understood that after reading the content taught by the present application, those skilled in the art can make various modifications or changes to the present application, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

[0025] Embodiments of the present application relate to a method for controlling the bending degree of a silicon sheet by thinning, as shown in Figures 1-5 The Bow optimization trend of the substrate, i.e., the bending degree tends to change to the positive direction or to the negative direction after epitaxy, is determined by analyzing the substrates and epitaxial wafers of different epitaxial specifications. The front and back thinning is respectively performed by selecting a thinning machine and a thinning grinding wheel, so that the geometric parameters of the silicon sheet can be accurately and batch-adjusted. The influence or change trend of the Bow value after the subsequent film forming or thermal history process meets the expectation, and the deterioration of the geometric parameters is reduced.

[0026] Embodiment one:

[0027] A method for controlling the bending degree of a silicon sheet by thinning, comprising the following operation steps:

[0028] S1, for the heavily doped boron substrate with a resistance of 0.005-0.025 ohm, cutting treatment is performed to obtain silicon sheets cut by the same machine at adjacent time, and the silicon sheets are processed together. Specifically, the silicon sheet is cut by using a wire cutting process, the cutting speed is controlled to be 0.5-1.5 mm / s, and the cutting accuracy is controlled to be within ±0.01 mm. The historical data of the bending degree of the epitaxial wafer and the bending degree of the substrate wafer of the same mass production epitaxial wafer are analyzed. The change trend of the bending degree after epitaxy, i.e., the bending degree tends to change to the positive direction, is set as the bending degree processing target range of the substrate wafer. The bending degree processing target of the substrate wafer is opposite to the change trend of the bending degree after epitaxy, i.e., the substrate tends to have a negative bending degree.

[0029] S2, one of the cut silicon sheets is taken out for trial processing and thinning, specifically including;

[0030] S21, the cut silicon wafer is fixed on the processing machine A of the thinning device by vacuum adsorption, the front surface of the first silicon wafer is thinned by the thinning device, the topography of the vacuum chuck table of the thinning device is adjusted according to the bending degree of the substrate wafer, and the state of the bearing surface of the vacuum chuck table will affect the bending degree of the thinned silicon wafer during wafer thinning; the side support part pressure at the bottom edge of the vacuum chuck table is adjusted by the edge pressure adjusting device at the bottom of the thinning equipment, so that the topography (adjustment value) of the vacuum chuck table is changed, as shown in Figure 3 , the topography is controlled by the edge air pressure of the vacuum chuck table, and experiments show that the topography 3 is obtained by reducing the edge air pressure, the front surface of the silicon wafer is processed, the differential thickness of the center and the edge of the front surface of the silicon wafer is realized, and thus the bending degree is adjusted; the first silicon wafer is fixed on the thinning machine A by vacuum adsorption (adsorption pressure 0.6-0.8 MPa), an 800-mesh diamond grinding wheel is used, the rotation speed is 1200 r / min, the feed speed is 1.0-1.5 mm / min, the front surface is thinned, the thickness reduction amount is controlled within 20 μm, and the surface roughness Ra of the thinned surface is ≤0.5 μm;

[0031] S22, the back surface of the same silicon wafer is fixed on the processing machine B of the thinning device by vacuum adsorption, and the back surface of the silicon wafer is thinned by the thinning device; the topography of the vacuum chuck table is adjusted according to the topography and law, the edge air pressure is increased to obtain the topography 1, the back surface of the silicon wafer is processed, the topography of the Chunktable affects the thickness reduction amount of the center and the edge during the thinning and thickness reduction process, that is, the thickness reduction amount of the edge of the silicon wafer is greater than that of the center of the silicon wafer, and the thinning topography of the front surface and the back surface is complementary and enhanced, so that the Bow value, that is, the bending degree of the silicon wafer can be accurately corrected towards the preset negative target value, as shown in Figure 4 ; the same grinding wheel type, rotation speed and feed speed as the front surface are used for back surface thinning, and the thickness reduction amount is also 20 μm;

[0032] S23, the first silicon wafer is thinned by the silicon wafer thinning equipment to obtain a processed first silicon wafer, and a topography of the processed first silicon wafer is obtained; the geometric parameters of the silicon wafer after trial processing are measured, the geometric parameters include the bending degree and the thickness map, the geometric parameters of the surface of the silicon wafer are obtained, the geometric parameters are used to indicate the microtopography characteristics of the surface of the silicon wafer, the topography is a 2D topography or a 3D topography, a machine adjustment judgment scheme is made, and the processing parameters of the silicon wafer thinning equipment are adjusted, that is, in the case that the microtopography characteristics indicated by the topography parameters are unqualified or do not meet the preset requirements, the topography of the vacuum chuck table of the thinning device is adjusted, so that the microtopography characteristics of the silicon wafer processed by the adjusted thinning device are accurately adjusted, and thus qualified or meet the preset requirements;

[0033] S24, by the topography control, test and analysis of the front and back, the topography of the vacuum chuck and the bending degree change trend of the silicon wafer are combined to realize the accurate control of the bending degree; if the bending degree does not reach the target value after adjusting the thinning parameter, the vacuum chuck of the thinning device is replaced, and the steps of S21-S23 are repeated until the micro-topography parameters of the trial processing silicon wafer meet the preset requirements, that is, the desired bending degree value is reached;

[0034] S3, a new silicon wafer is taken for conventional thinning processing, the bending degree value of the thinned silicon wafer is measured, and the conventional thinning process is compared with the above new processing process;

[0035] S4, the silicon wafer of the conventional thinning process and the silicon wafer of the new processing process are subjected to epitaxial growth, and the geometric parameters of the epitaxial wafer are measured and analyzed after epitaxial growth, and the technical effects are as shown in Figure 2 The absolute value of the Bow of the substrate wafer after thinning parameter optimization is effectively reduced after epitaxial growth.

[0036] Example two:

[0037] A method for controlling the bending degree of a silicon wafer by thinning, comprising the following operation steps:

[0038] S1, the heavily doped arsenic substrate silicon wafer with a resistance of 0.001-0.05 ohm is subjected to cutting treatment, the silicon wafers cut by the same machine in adjacent time are obtained, and these silicon wafers are processed together; specifically, the silicon wafer is cut by using a wire cutting process, the cutting speed is controlled to be 0.5-1.5 mm / s, and the cutting accuracy is controlled to be within ±0.01 mm; the historical data of the epitaxial wafer bending degree and the substrate wafer bending degree of the same production epitaxial wafer are analyzed, the bending degree processing target range of the substrate wafer is set through the change trend of the bending degree after epitaxial growth, that is, the bending degree after epitaxial growth tends to change in the negative direction, and the bending degree processing target of the substrate wafer is opposite to the change trend of the bending degree after epitaxial growth, that is, the substrate tends to have a positive bending degree;

[0039] S2, one of the cut silicon wafers is taken for trial processing thinning, specifically including;

[0040] S21, the cut silicon wafer is fixed on the processing machine A of the thinning device by vacuum adsorption, the front surface of the first silicon wafer is thinned by the thinning device, the topography of the vacuum chuck (Chucktable) of the thinning device is adjusted according to the bending degree processing target of the substrate wafer, and the state of the bearing surface of the vacuum chuck will affect the bending degree of the thinned silicon wafer during the wafer thinning process; the side support part pressure of the bottom edge of the vacuum chuck is adjusted by the edge pressure adjusting device at the bottom of the thinning equipment, so as to change the topography (Adjustment Value) of the vacuum chuck, as Figure 3As shown, the topography is controlled by the edge air pressure of the vacuum chuck. According to the experiment, increasing the edge air pressure obtains topography 1, and the front surface of the wafer is processed. The difference between the center and the edge of the front surface of the wafer is realized, that is, the thickness of the center is less than that of the edge, so as to adjust the bending degree. The first wafer is fixed on the thinning machine A by vacuum adsorption (adsorption pressure 0.6-0.8 MPa), and the front surface is thinned by using an 800-mesh diamond grinding wheel at a speed of 1200 r / min and a feed rate of 1.0-1.5 mm / min. The thickness is controlled at 20 μm, and the surface roughness Ra after thinning is less than or equal to 0.5 μm.

[0041] S22, the back surface of the same wafer is fixed on the processing machine B of the thinning device by vacuum adsorption, and the back surface of the wafer is thinned by the thinning device. According to the topography and rule of the vacuum chuck, the edge air pressure is increased to obtain topography 3, and the back surface of the wafer is processed. During the thinning and thickness reduction process, the Chunktable topography affects the thickness of the center and the edge, that is, the thickness of the edge of the wafer is less than that of the center. The front and back thinning topographies are mutually coordinated and enhanced, so that the Bow value, that is, the bending degree of the wafer during the thinning process can be accurately corrected towards the preset positive target value, as shown in Figure 5 The same grinding wheel type, speed and feed rate as the front surface are used for back surface thinning, and the thickness is also 20 μm.

[0042] S23, the first wafer is ground and processed by the thinning device to obtain a processed first wafer, and the topography of the processed first wafer is obtained. The geometric parameters of the wafer after trial processing are measured, including the bending degree and the thickness map. The geometric parameters of the wafer surface are obtained, which are used to indicate the micro-topographic features of the wafer surface. The topography is a 2D topography or a 3D topography. A machine adjustment judgment scheme is made, and the processing parameters of the thinning device are adjusted. That is, in the case that the micro-topographic features indicated by the topography parameters are unqualified or do not meet the preset requirements, the micro-topographic features of the wafer processed by the adjusted thinning device are accurately adjusted, so as to be qualified or meet the preset requirements.

[0043] S24, the topography of the vacuum chuck and the bending degree change trend of the wafer are combined by controlling, testing and analyzing the topography of the front and back surfaces, so as to realize accurate control of the bending degree. If the bending degree does not reach the target value after adjusting the thinning parameters, the vacuum chuck of the thinning device is replaced, and the steps of S21-S23 are repeated until the micro-topographic parameters of the trial-processed wafer meet the preset requirements, that is, the desired bending degree value is reached.

[0044] S3, a new wafer is taken for conventional thinning processing, and the bending degree value of the thinned wafer is measured. The conventional thinning process is compared with the above new processing process.

[0045] S4, epitaxial growth is performed on the silicon wafer of the conventional thinning process and the silicon wafer of the new processing process, and after the epitaxial growth, the geometric parameters of the epitaxial wafer are measured and analyzed.

[0046] The method in the embodiment one and the embodiment two is to ensure that the influence or the change trend of the subsequent film forming or thermal history process on the bow value meets the expectation, and reduce the deterioration of the geometric parameters.

[0047] In the embodiment one, the preset range of the desired bow value in the S24 is -15-0 μm.

[0048] In the embodiment two, the preset range of the desired bow value in the S24 is 0-15 μm.

[0049] In the embodiment one and the embodiment two, the first grinding wheel of the thinning device A and the second grinding wheel of the thinning device B are both diamond grinding wheels, the granularity is 800-1200 mesh, and the grinding speed is 1000-1500 r / min.

[0050] In the embodiment one and the embodiment two, the silicon wafer is a heavily boron-doped or heavily arsenic-doped substrate silicon wafer as a preferred solution, but the method of the present application is applicable to various back surface structures and various doping types including different resistivities.

[0051] In the embodiment one and the embodiment two, the bow value is measured by using the Wafersight white light interferometer produced by KLA company.

[0052] In the description of the present application, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, perpendicular, horizontal" and "top, bottom" and the like indicate the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and in the absence of the opposite description, these orientation words do not indicate and imply that the indicated device or element must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection scope of the present application; the orientation words "inner, outer" refer to the inner and outer relative to the contour of each component.

[0053] For purposes of the description hereinafter, spatial

[0054] In addition, it should be noted that the use of "first", "second", etc. words to define parts, only for the convenience of the corresponding parts are distinguished, such as no further declaration, the above words have no special meaning, therefore can not be understood as the limitation of the scope of protection of the present application.

[0055] The above is a detailed introduction to the method for controlling the bending degree of a thinned control silicon wafer provided by the present application. The principles and implementation modes of the present application are described in this paper by using specific examples. The above example is only used to help understand the method of the present application and its core idea. Meanwhile, for those skilled in the art, the specific implementation modes and application ranges will be changed according to the idea of the present application. In summary, the content of the specification should not be understood as a limitation of the present application.

Claims

1. A method for controlling the curvature of a silicon wafer by thinning, characterized in that: The following steps are included: S1. Cut the silicon wafer to obtain the cut silicon wafer. Analyze the historical data of the curvature of the epitaxial wafer and the substrate wafer of the same mass-produced epitaxial wafer. Based on the trend of the change in curvature after epitaxy, set the target range for the curvature of the substrate wafer. S2. Take out one of the cut silicon wafers and perform trial thinning, specifically including: S21. The cut silicon wafer is fixed on the processing table A of the thinning device by vacuum adsorption. The front side of the first silicon wafer is thinned by the thinning device. According to the processing target of the substrate curvature, the shape of the vacuum chuck of the thinning device is adjusted. During the wafer thinning process, the state of the bearing surface of the vacuum chuck will affect the curvature of the thinned silicon wafer. The pressure of the side support part at the bottom edge of the vacuum chuck is adjusted by the suction edge pressure adjustment device at the bottom of the thinning device, thereby changing the shape of the vacuum chuck. S22. The back side of the same silicon wafer is fixed on the processing table B of the thinning device by vacuum adsorption. The thinning device is used to thin the back side of the silicon wafer. According to the shape and pattern of the vacuum chuck, the front and back thinning shapes are adjusted to complement and enhance each other, so that the Bow value, i.e. the curvature, of the silicon wafer can be accurately corrected towards the preset negative target value during the thinning process. S23. The first silicon wafer is ground using a thinning device to obtain a processed first silicon wafer, and a morphology image of the processed first silicon wafer is obtained; the geometric parameters of the silicon wafer after trial processing are measured, including curvature and thickness, and the geometric parameters of the silicon wafer surface are obtained. The geometric parameters are used to indicate the microscopic morphological features of the silicon wafer surface. The morphology image is a 2D morphology image or a 3D morphology image. A machine adjustment judgment plan is made, and the processing parameters of the thinning device are adjusted. That is, when the morphology parameters indicate that the microscopic morphological features are unqualified or do not meet the preset requirements, the morphology of the vacuum chuck of the thinning device is adjusted so that the microscopic morphological features of the silicon wafer processed by the thinning device are precisely adjusted, thereby becoming qualified or meeting the preset requirements; S24. By controlling, testing and analyzing the morphology of the front and back sides, the morphology of the vacuum chucks on the front and back sides and the trend of the curvature of the silicon wafer are combined to achieve precise control of the curvature. If the curvature does not reach the target value after adjusting the thinning parameters, the vacuum chuck of the thinning equipment is replaced and the steps of S21-S23 are repeated until the micromorphology parameters of the trial-processed silicon wafer meet the preset requirements, that is, the desired curvature value is achieved. S3. Take a new silicon wafer and perform conventional thinning processing. Measure the curvature value of the thinned silicon wafer and compare the conventional thinning process with the new processing process described above. S4. Perform epitaxial growth on silicon wafers using conventional thinning processes and silicon wafers using new processing processes. After epitaxial growth, measure and analyze the geometric parameters of the epitaxial wafers.

2. The method for controlling silicon wafer curvature by thinning according to claim 1, characterized in that: In S1, the cutting process adopts wire cutting technology, the cutting speed is 0.5 to 1.5 mm / s, and the cutting accuracy is controlled within ±0.01 mm.

3. The method for controlling silicon wafer curvature by thinning according to claim 1, characterized in that: The first grinding wheel of the thinning device A and the second grinding wheel of the thinning device B are both diamond grinding wheels with a grit size of 800-1200 mesh and a grinding speed of 1000-1500 r / min.

4. The method for controlling silicon wafer curvature by thinning according to claim 1, characterized in that: The curvature value was measured using a white light interferometer.

5. The method for controlling the curvature of a silicon wafer by thinning according to claim 1, characterized in that: The amount of thickness removed from the front and back sides during the thinning process is within 50 μm.

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