Grinding device

Abstract

The present invention provides a polishing apparatus that improves the uniformity of wafer thickness. The polishing apparatus (10) includes: a chuck stage (21) for holding a wafer (W) so that it can rotate; a processing unit (14) having a grinding stone (41) for processing the wafer (W) using the rotating grinding stone (41); and a control unit (16) for controlling the relative tilt between the grinding stone rotation axis (O3) of the grinding stone (41) and the stage rotation axis (O1) of the chuck stage (21). The control unit (16) controls the relative tilt between the grinding stone rotation axis (O3) of the grinding stone (41) and the stage rotation axis (O1) of the chuck stage (21) based on the variation characteristics of the tilt of the grinding stone rotation axis (O3) of the grinding stone (41) relative to the polishing load when polishing the chuck stage (21) with the grinding stone (41).

Description

Technical Field

[0001] This disclosure relates to grinding apparatus. Background Technology

[0002] In the semiconductor manufacturing field, back polishing is performed to grind the back side of a wafer in order to form a thin film. Patent Document 1 discloses a polishing apparatus that uses a rotating polishing stone to polish the back side of a wafer held by a chuck. Existing technical documents Patent documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2013-212571 Summary of the Invention The problem that the invention aims to solve

[0004] In grinding equipment, it is required to improve the uniformity of the thickness of the ground wafer. Solution for solving the problem

[0005] A polishing apparatus according to one aspect of this disclosure includes: a chuck stage for holding a wafer in a rotatable position; a processing unit having an abrasive stone for processing the wafer using the rotating abrasive stone; and a control unit for controlling the relative tilt between the rotation axis of the abrasive stone and the rotation axis of the chuck stage. The control unit controls the relative tilt between the rotation axis of the abrasive stone and the rotation axis of the chuck stage based on at least one of the variation characteristics of the tilt of the rotation axis of the abrasive stone relative to the polishing load when polishing the chuck stage with the abrasive stone and the variation characteristics of the tilt of the rotation axis of the chuck stage relative to the polishing load. Invention Effects

[0006] According to one aspect of this disclosure, a polishing apparatus is provided that improves the uniformity of wafer thickness. Attached Figure Description

[0007] Figure 1 This is a perspective view showing a simplified structure of the grinding apparatus according to the first embodiment. Figure 2 This is a simplified top view showing the structure surrounding the moving part and the measuring part. Figure 3 This is a simplified side view showing the holding section and the machining section. Figure 4 This is a simplified top view showing the holding section and the machining section. Figure 5 This is a simplified cross-sectional view showing the structure of the retaining part. Figure 6This is a simplified cross-sectional view showing the holding section, wafer, and measuring section. Figure 7 This is a simplified cross-sectional view showing the grinding of the chuck table. Figure 8 This is a simplified cross-sectional view showing the grinding of a wafer. Figure 9 This is a simplified top view showing the variation in the tilt of the grinding stone's axis of rotation. Figure 10 This is a simplified side view showing the holding part and the processing part of the grinding apparatus according to the second embodiment. Figure 11 This is a simplified top view showing the variation characteristics of the tilt angle of the chuck table. Figure 12 This is a simplified cross-sectional view showing the retaining part and the inclined part. Figure 13 This is a simplified top view of the indexing table of the grinding apparatus, representing a modified example. Figure 14 This is a simplified side view of the processing section and holding section of the grinding apparatus in a modified example. Detailed Implementation

[0008] (First Implementation) Reference Figures 1-9 The grinding apparatus 10 of the first embodiment will be described. (Overview of the grinding apparatus) Figure 1 This is a perspective view showing an example of the simplified structure of the grinding apparatus 10. In the following description, the X-axis and Y-axis directions of the mutually orthogonal XYZ axes shown in the figure represent the horizontal direction, and the Z-axis direction represents the height direction (vertical direction). In the following description, the Z-axis direction is sometimes set as the height direction. In addition, unless otherwise explicitly stated, the term "view from above" used in the following description refers to viewing the object along the Z-axis direction.

[0009] like Figure 1 As shown, the grinding apparatus 10 includes a housing 11, a holding part 12, a moving part 13, a processing part 14, a measuring part 15, and a control part 16. The grinding apparatus 10 is configured such that the wafer W held by the holding part 12 is moved to a position to be processed by the processing part 14 using the moving part 13, and then processed by the processing part 14. The wafer W is an example of a workpiece that is processed in the grinding apparatus 10. The grinding apparatus 10 thins the wafer W by grinding the upper surface Wa of the wafer W held by the holding part 12. The housing 11 is covered by a dustproof and dripproof cover, etc., and houses the holding part 12, the moving part 13, the processing part 14, the measuring part 15, and the control part 16.

[0010] (Structure of the grinding device) Figure 2 This is a schematic top view showing the periphery of the moving part 13 and the measuring part 15 in the grinding apparatus 10. Figure 3 This is a simplified side view showing the holding part 12 and the machining part 14. Figure 4 This is a simplified top view showing the holding part 12 and the machining part 14. Figure 5 This is a partial cross-sectional view showing the structure of the inclined portion 23 of the retaining portion 12. Figure 6 This is a simplified cross-sectional view showing the holding part 12 and the measuring part 15.

[0011] (Maintenance Department) like Figures 2-6 As shown, in one example, the holding part 12 is configured to hold the wafer W by adsorption. The holding part 12 holds the wafer W so that it can rotate. The holding part 12 includes a chuck stage 21 for holding the wafer W by adsorption and a support part 22 for supporting the chuck stage 21 so that it can rotate. The holding part 12 includes an inclined part 23 for tilting the stage rotation axis O1 of the chuck stage 21, that is, the wafer rotation axis O2 of the wafer W.

[0012] The chuck stage 21 has a wafer holding surface 21a for holding the wafer W. The chuck stage 21 is configured to hold the wafer W by adsorption. In one example, such as Figure 6 As shown, an adsorbent 24 made of a porous material such as alumina is embedded in the chuck stage 21. Inside the chuck stage 21, there is a (not shown) conduit extending to the side opposite to the wafer holding surface 21a. The conduit is connected to a vacuum source, a compressed air source, or a water supply. The wafer W is held on the wafer holding surface 21a of the chuck stage 21 by the vacuum source. The wafer W is released from the wafer holding surface 21a by the compressed air source or the water supply.

[0013] The chuck stage 21 is driven by a drive unit (not shown) including a motor and other drive mechanisms, and rotates in one direction around the stage rotation axis O1. As a result, the wafer W held in the chuck stage 21 rotates around the stage rotation axis O1 (the wafer rotation axis O2 of the wafer W) of the chuck stage 21.

[0014] The tilting portion 23 is configured to tilt the table rotation axis O1 of the chuck table 21 relative to the grinding stone rotation axis O3 of the grinding stone 41. In one example, the tilting portion 23 may be provided in the holding portion 12. The tilting portion 23 provided in the holding portion 12 is configured to tilt the table rotation axis O1 of the chuck table 21 relative to the grinding stone rotation axis O3 of the grinding stone 41.

[0015] The inclined section 23 includes an inclined worktable 31 for mounting the support section 22, a fixed support section 32, and two movable support sections 33. In one example, the tilting table 31 has a triangular shape when viewed from above. The tilting table 31 is provided with a fixed support 32 and two movable supports 33. The fixed support 32 and the two movable supports 33 are arranged at equal angular intervals around the table's rotation axis O1. Alternatively, the number of movable supports 33 can be appropriately changed to three or more.

[0016] The fixed support 32 is fastened to the inclined worktable 31 by bolts 34. Both movable support portions 33 have the same structure. The movable support portion 33 includes a nut 35 embedded in the tilting worktable 31, a tilting ball screw 36 fixed to the movable worktable 13a of the movable portion 13 and screwed to the nut 35 at its upper part, and a tilting motor 37 for rotating the tilting ball screw 36. The movable support portion 33 is formed to be longer than the fixed support portion 32 in the Z-axis direction.

[0017] The grinding apparatus 10 may also include a scale 38 for detecting the movement of the tilting stage 31. The tilting stage 31 sinks due to the load when the processing unit 14 presses the wafer W, thereby moving in the height direction. The amount of movement of the tilting stage 31 can be regarded as the movement of the chuck stage 21 that holds the wafer W. That is, the scale 38 is used to detect the amount of movement of the chuck stage 21, which corresponds to the grinding load when the processing unit 14 performs grinding processing on the wafer W. Therefore, it can also be said that the scale 38 is used to detect the grinding load of the processing unit 14.

[0018] (Mobile Department) The moving part 13 is configured to move the holding part 12 relative to the processing part 14. In one example, the moving part 13 is configured to move the holding part 12 relative to the processing part 14.

[0019] The moving part 13 includes: a moving worktable 13a having a holding part 12; a guide part 13b for linearly moving the moving worktable 13a; and a drive part 13c for moving the moving worktable 13a. The guide part 13b and the moving worktable 13a constitute a linear worktable that moves the holding part 12 in a linear manner.

[0020] The moving part 13 is configured to move the holding part 12 between a polishing position P1 and a non-polishing position P2. The polishing position P1 is the position where the wafer W held in the holding part 12 is processed by the processing part 14. The non-polishing position P2 is the position where the wafer W is not processed. In one example, the non-polishing position P2 is the position where the wafer W is placed on the chuck stage 21 and the wafer W is attracted to it.

[0021] The polishing apparatus 10 processes multiple wafers W sequentially by reciprocating the holding portion 12 between a non-polishing position P2 and a polishing position P1. Specifically, the polishing apparatus 10 holds the wafers W in the holding portion 12 at the non-polishing position P2, and moves the wafers W and the holding portion 12 in a straight line to the polishing position P1 by the movement of the moving portion 13. Furthermore, the polishing apparatus 10 moves the polished wafers W and the holding portion 12 in a straight line from the polishing position P1 to the non-polishing position P2.

[0022] (Processing Department) The processing unit 14 has a grinding stone 41, which is configured to process the wafer W using the grinding stone 41.

[0023] In one example, the processing unit 14 includes a plurality of grinding stones 41, a grinding wheel 42 on which the plurality of grinding stones 41 are mounted, and a spindle 43 for rotating the grinding wheel 42. In one example, the spindle 43 includes a rotating shaft for mounting and supporting the grinding wheel 42 so that it can rotate; and a motor 43a for driving the rotating shaft. The spindle 43 is configured such that the grinding wheel 42 rotates about the grinding wheel rotation axis O3 via the motor 43a. The grinding wheel 42 has a circular plate shape centered on the grinding wheel rotation axis O3. The plurality of grinding stones 41 are mounted on the grinding wheel retaining surface 42a of the grinding wheel 42. The plurality of grinding stones 41 are arranged on the circumference of the grinding wheel 42 centered on the grinding wheel rotation axis O3.

[0024] It can be said that the processing unit 14 is configured to make the grinding stone 41 rotate around the grinding stone rotation axis O3. The grinding stone rotation axis O3 of the grinding stone wheel 42 can be said to be the grinding stone rotation axis O3 of the grinding stone 41 mounted on the grinding stone wheel 42.

[0025] The processing unit 14 includes a spindle feed unit 44. The spindle feed unit 44 is configured to allow the processing unit 14 to move along the Z-axis. The grinding apparatus 10 uses the spindle feed unit 44 to press the grinding stone 41 of the processing unit 14 against the wafer W to perform grinding processing on the wafer W. The area where the grinding stone 41 grinds the wafer W is defined as the grinding area A1.

[0026] like Figure 3 , Figure 4 As shown, the grinding wheel 42 that holds the grinding stones 41 and the chuck stage 21 that holds the wafer W are arranged with their rotation axes O1 (O2) and O3 offset when viewed from the Z-axis. In one example, when viewed from the Z-axis, the grinding wheel 42 is arranged in a circle formed by multiple grinding stones 41, which overlaps with the stage rotation axis O1 of the chuck stage 21. Thus, the grinding area A1 of the grinding stones 41 extends from the wafer center O2 to the outer periphery of the wafer W, and has an arc shape that corresponds to the circle formed by multiple grinding stones 41.

[0027] The spindle feed unit 44 includes: two connecting portions 46 connecting the column 45 and the machining unit 14; and a drive portion 47 for moving the machining unit 14 relative to the column 45. The column 45 is, for example, fixed to... Figure 1 The housing 11 is shown. The column 45 may also be included within the housing 11. The two connecting portions 46 are, for example, linear guides. Each of the two connecting portions 46 has a guide rail 46a and two movable base portions 46b supported by the guide rail 46a. The guide rail 46a is mounted to the column 45 in a manner extending along the Z-axis direction. The base portions 46b are mounted to the base member 14a of the machining section 14.

[0028] The drive unit 47 may be, for example, a ball screw slider mechanism including a motor 47a and a ball screw that rotates under the action of the motor 47a. The drive unit 47 causes the base member 14a of the machining unit 14 to move relative to the column 45 along the Z-axis direction. As a result, the machining unit 14 moves along the height direction.

[0029] (Measurement Department) like Figure 2 , Figure 6 As shown, the grinding apparatus 10 includes a measuring unit 15. The measuring unit 15 may also include a shape measuring unit 51.

[0030] The shape measuring unit 51 measures the shape of the wafer W. In one example, the shape of the wafer W is its thickness. The shape measurement unit 51 includes sensor heads 51a and 51b for measuring the shape of the wafer W. In one example, sensor heads 51a and 51b are contact-type height measuring devices. Sensor head 51a is configured to contact the upper surface Wa of the wafer W. Sensor head 51b is configured to measure the position of the lower end that contacts the upper surface of the wafer W. Sensor head 51b is positioned closer to the outer periphery of the chuck stage 21 than sensor head 51a. Sensor head 51b is configured to contact the wafer holding surface 21a of the chuck stage 21. Sensor head 51b is configured to measure the height of the lower end that contacts the wafer holding surface 21a of the chuck stage 21. The shape measurement unit 51 is configured to measure the difference between the measurements taken by sensor heads 51a and 51b as the thickness of the wafer W.

[0031] (Control Department) The control unit 16 may consist of, for example, a computer system including a CPU, memory, input devices, output devices, and a sequencer. The input devices may be provided for inputting instructions from the operator regarding the grinding device 10. Input devices may include touch panels, keyboards, mice, etc. Non-contact devices based on sensors may also be used as input devices. The output unit may be provided for outputting processing results from the grinding device 10, notification information from the grinding device 10 to the operator, etc. The output unit may be an LCD display, etc. For example, the output unit may output processing results and notification information via a network. The functions of the control unit 16 can be implemented through software control or through hardware operation.

[0032] In one example, the control unit 16 is comprised of a computer system. Software to be implemented by the control unit 16 is pre-loaded into memory. The control unit 16 performs the polishing process of the wafer W according to the steps outlined in the software.

[0033] The control unit 16 controls the moving unit 13, specifically the drive unit 13c of the moving unit 13, causing the moving stage 13a to reciprocate between the polishing position P1 and the non-polishing position P2. At the non-polishing position P2, the wafer W is placed on the chuck stage 21. The control unit 16 controls a vacuum source (not shown) to hold the wafer W on the wafer holding surface 21a of the chuck stage 21.

[0034] The control unit 16 moves the movable stage 13a to the grinding position P1, thereby moving the wafer W to the grinding position P1. Furthermore, the control unit 16 uses the grinding stone 41 of the processing unit 14 to perform grinding on the wafer W.

[0035] The control unit 16 rotates the grinding stone 41 via the spindle 43, and also rotates the wafer W held in the chuck stage 21. Furthermore, the control unit 16 moves the grinding stone 41 toward the wafer W via the spindle feed unit 44. The control unit 16 presses the grinding stone 41 against the wafer W via the spindle feed unit 44, thus performing grinding processing on the wafer W using the grinding stone 41.

[0036] The control unit 16 controls the relative tilt of the wafer W and the grinding stone 41 during the grinding process. In one example, the control unit 16 tilts the table rotation axis O1 of the chuck stage 21, which holds the wafer W in place, relative to the grinding stone rotation axis O3 of the grinding stone 41 to grind the wafer W. The control unit 16 measures the thickness of the wafer W during the grinding process and performs feedback control to adjust the tilt of the chuck stage 21 based on the cross-sectional shape of the wafer W. By utilizing the tilt of the chuck stage 21, the unevenness of the wafer W's thickness can be reduced, thereby improving the flatness and parallelism of the wafer W.

[0037] The control unit 16 stores at least one of the variation characteristics of the tilt angle of the grinding wheel rotation axis O3 of the grinding wheel 41 relative to the grinding load and the variation characteristics of the tilt angle of the chuck table rotation axis O1 of the chuck table 21 relative to the grinding load. In one example, the grinding load can be the grinding load when the grinding wheel 41 grinds the chuck table 21. It can be said that the control unit 16 stores at least one of the variation characteristics of the tilt angle of the grinding wheel rotation axis O3 of the grinding wheel 41 relative to the grinding load when the grinding wheel 41 grinds the chuck table 21 and the variation characteristics of the tilt angle of the chuck table 21 rotation axis O1 relative to the grinding load. The variation characteristics are stored, for example, in a memory. Based on the variation characteristics, the control unit 16 controls the relative tilt angle of the grinding wheel rotation axis O3 of the grinding wheel 41 and the chuck table rotation axis O1 of the chuck table 21 according to the grinding load when grinding the wafer W with the grinding wheel 41. This improves the flatness and parallelism of the wafer W.

[0038] like Figure 3 As shown, the control unit 16 of the first embodiment stores a variation characteristic 62a of the inclination of the grinding wheel rotation axis O3 of the grinding wheel 41 relative to the grinding load when the grinding wheel 41 is used to grind the chuck table 21. Variation characteristic 62a is a data table that correlates the grinding load of the grinding wheel 41 with the orientation and amount of the inclination of the grinding wheel rotation axis O3 of the grinding wheel 41 relative to that grinding load. The grinding load is the load when the grinding wheel 41 is used to grind the chuck table 21. The grinding load is, for example, determined by… Figure 5 The scale 38 shown is used for detection. The tilt of the grinding wheel rotation axis O3 of the grinding wheel 41 is detected, for example, by a detection unit 61a provided on the main shaft 43 that rotates the grinding wheel 42 on which the grinding wheel 41 is mounted. The detection unit 61a may also be configured to detect the tilt of the rotation axis on which the grinding wheel 42 is mounted and supported so that it can rotate.

[0039] like Figure 7 As shown, the control unit 16 rotates the chuck stage 21 and the grinding stone 41. The control unit 16 presses the grinding stone 41 against the wafer holding surface 21a of the chuck stage 21, and the grinding stone 41 performs grinding on the wafer holding surface 21a of the chuck stage 21. At this time, the control unit 16 detects the grinding load pressing against the grinding stone 41 and the tilt of the grinding stone rotation axis O3 of the grinding stone 41. Furthermore, the control unit 16 stores the variation characteristic 62a that correlates the grinding load with the grinding stone rotation axis O3.

[0040] Figure 9 An example of the variation characteristic 62a is shown. Figure 9 The variation characteristic 62a shown represents the change in the orientation of the grinding wheel rotation axis O3 relative to the grinding load. Figure 9The characteristic points 63a of the variation characteristic 62a shown represent the trajectory of the normal vector of the grinding wheel 42's grinding holding surface 42a. The normal vector includes the grinding load and the normal direction of the grinding holding surface 42a relative to the grinding load.

[0041] Characteristic point 63a is referenced to the normal direction of the grinding stone holding surface 42a when the grinding load is "0". Characteristic point 63a shows the direction in which the grinding load and the grinding stone rotation axis O3 are tilted under the action of the grinding load when viewed from the direction along the grinding stone rotation axis O3 of the grinding stone holding surface 42a when the grinding load is "0". Therefore, the wafer holding surface 21a of the chuck stage 21 ground by the grinding stone 41 is tilted in the normal direction of the grinding stone holding surface 42a corresponding to the grinding load.

[0042] like Figure 8 As shown, the control unit 16 holds the wafer W on the wafer holding surface 21a of the chuck stage 21. The control unit 16 rotates the chuck stage 21 holding the wafer W and also rotates the grinding stone 41. Furthermore, the control unit 16 presses the grinding stone 41 against the wafer W, and the grinding stone 41 performs grinding processing on the wafer W. At this time, the control unit 16 controls the inclination of the grinding stone rotation axis O3 of the grinding stone 41 according to the grinding load when grinding the wafer W based on the variation characteristic 62a.

[0043] The lower surface Wb of the wafer W held by the chuck stage 21 mimics the wafer holding surface 21a. The variation characteristic 62a represents the tilt angle of the grinding stone rotation axis O3 of the grinding stone 41 relative to the grinding load when grinding the wafer holding surface 21a of the chuck stage 21. Thus, the tilt angle of the grinding stone rotation axis of the grinding stone 41 used to grind the wafer W is controlled based on the variation characteristic 62a. For example, by controlling the tilt angle of the grinding stone rotation axis of the grinding stone 41 used to grind the wafer W to make the wafer holding surface 21a parallel to the grinding stone holding surface 42a, the grinding stone holding surface 42a can be made parallel to the wafer holding surface 21a of the chuck stage 21. Therefore, the lower surface Wb of the wafer W held on the wafer holding surface 21a of the chuck stage 21 can be made parallel to the upper surface Wa of the wafer W after grinding by the grinding stone 41. That is, the parallelism between the upper surface Wa and the lower surface Wb in the wafer W can be improved, thereby improving the overall thickness uniformity of the wafer W. Furthermore, by controlling the inclination of the grinding wheel rotation axis of the grinding wheel 41 for grinding the wafer W, the wafer W can be ground into a desired cross-sectional shape.

[0044] (Effects of the first implementation method) The effects of the first embodiment will be explained. (1-1) The grinding apparatus 10 includes: a chuck table 21 for holding the wafer W so that it can rotate; a processing unit 14 having a grinding stone 41 for processing the wafer W using the rotating grinding stone 41; and a control unit 16 for controlling the relative tilt between the grinding stone rotation axis O3 of the grinding stone 41 and the table rotation axis O1 of the chuck table 21.

[0045] The control unit 16 controls the relative tilt of the grinding wheel rotation axis O3 of the grinding wheel 41 and the table rotation axis O1 of the chuck table 21 based on the variation characteristics of the tilt of the grinding wheel rotation axis O3 of the grinding wheel 41 relative to the grinding load when the grinding wheel 41 is used to grind the chuck table 21, according to the grinding load when the wafer W is ground by the grinding wheel 41.

[0046] By controlling the tilt of the grinding stone rotation axis of the grinding stone 41 that grinds the wafer W based on the variation characteristic 62a, the grinding stone holding surface 42a can be made parallel to the wafer holding surface 21a of the chuck stage 21. Therefore, the parallelism between the upper surface Wa and the lower surface Wb in the wafer W can be improved, thereby improving the overall thickness uniformity of the wafer W.

[0047] (1-2) The grinding apparatus 10 includes a shape measuring unit 51 for measuring the shape of the wafer W. The control unit 16 controls the relative tilt of the grinding stone rotation axis O3 of the grinding stone 41 and the table rotation axis O1 of the chuck table 21 based on the grinding load and the shape of the wafer measured by the shape measuring unit 51. Therefore, by controlling the tilt of the grinding stone rotation axis of the grinding stone 41 that grinds the wafer W, the wafer W can be ground into a shape with the desired cross-sectional shape.

[0048] (Second Implementation) Reference Figure 10 , Figure 11 The grinding apparatus 10 of the second embodiment will be described. Regarding the grinding apparatus 10 of the second embodiment, the same reference numerals are used for the same components as those in the grinding apparatus 10 of the first embodiment. Hereinafter, descriptions of components that are the same as those in the first embodiment will be omitted, while descriptions of components that are different from those in the first embodiment will be provided.

[0049] The grinding apparatus 10 of the second embodiment differs from the grinding apparatus 10 of the first embodiment in that it is controlled based on the control unit 16. Therefore, the control based on the control unit 16 will be described. like Figure 10As shown, the control unit 16 stores the variation characteristic 62b of the tilt angle of the chuck table 21's rotation axis O1 relative to the grinding load. In one example, the grinding load can be the grinding load when the chuck table 21 is ground using a grinding stone 41. Alternatively, the control unit 16 stores the variation characteristic 62b of the tilt angle of the chuck table 21's rotation axis O1 relative to the grinding load when the chuck table 21 is ground using a grinding stone 41. The variation characteristic 62b is a data table that correlates the grinding load of the grinding stone 41 with the orientation and amount of the tilt angle of the chuck table 21 relative to that grinding load. The tilt angle of the chuck table 21's rotation axis O1 is detected, for example, by a detection unit 61b provided on a support 22 that supports the chuck table 21 for rotation. The detection unit 61b can also be configured to detect the tilt angle of the rotation axis of the chuck table 21. Similar to the first embodiment, the variation characteristic 62b can be obtained when the chuck table 21 is polished using the grinding stone 41.

[0050] Figure 11 An example of variable characteristic 62b is shown. Figure 11 The variation characteristic 62b shown represents the change in the posture of the chuck table 21 relative to the grinding load. Figure 11 The characteristic points 63b of the variation characteristic 62b shown represent the trajectory of the normal vector of the wafer holding surface 21a of the chuck stage 21. The normal vector includes the polishing load and the normal direction of the wafer holding surface 21a relative to the polishing load.

[0051] Characteristic point 63b is referenced to the normal direction of the wafer holding surface 21a when the grinding load is "0". Characteristic point 63b indicates the grinding load and the direction in which the stage rotation axis O1 tilts under the action of the grinding load when viewed from the direction along the stage rotation axis O1 of the wafer holding surface 21a when the grinding load is "0".

[0052] The control unit 16 uses a grinding stone 41 to grind the wafer W held on the wafer holding surface 21a of the chuck stage 21. At this time, the control unit 16 controls the tilt of the stage rotation axis O1 of the chuck stage 21 according to the grinding load when grinding the wafer W based on the variation characteristic 62b.

[0053] (Effects of the second implementation method) The effects of the second embodiment will be explained. (2-1) The control unit 16 of the grinding apparatus 10 controls the relative tilt of the grinding wheel rotation axis O3 of the grinding wheel 41 to the relative tilt of the grinding load when the grinding wheel 41 is used to grind the chuck table 21 based on the variation characteristic 62b of the tilt of the table rotation axis O1 of the chuck table 21 to the grinding load when the wafer W is ground by the grinding wheel 41.

[0054] By controlling the tilt of the grinding stone rotation axis of the grinding stone 41 that grinds the wafer W based on the variation characteristic 62b, the grinding stone holding surface 42a can be made parallel to the wafer holding surface 21a of the chuck stage 21. Therefore, the parallelism between the upper surface Wa and the lower surface Wb in the wafer W can be improved, thereby improving the overall thickness uniformity of the wafer W.

[0055] (Example of amendment) This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other within the scope of technical inconsistency.

[0056] The structure of the grinding device 10 can also be modified appropriately. like Figure 12 As shown, a load sensor 55 for measuring the grinding load can also be provided. In one example, the load sensor 55 can be provided between the tilting table 31 and the support 22. Multiple load sensors 55 can also be provided around the table rotation axis O1 of the chuck table 21.

[0057] By setting multiple load sensors 55, the tilt of the table rotation axis O1 of the chuck table 21 can also be detected. The polishing apparatus 10 may also be equipped with a sensor that uses light or ultrasound to measure the thickness of the wafer W. For example, a light sensor can be used to measure the thickness of the wafer W based on the optical path difference between the reflected light from the upper surface Wa of the wafer W and the reflected light from the lower surface Wb.

[0058] The grinding apparatus 10 can also be configured to move the wafer W held on the chuck stage 21 toward the grinding stone 41. Alternatively, the grinding apparatus 10 can be configured to move both the grinding stone 41 and the chuck stage 21.

[0059] In one embodiment, the wafer W and the chuck stage 21 are moved in a linear reciprocating motion between the non-grinding position P2 and the grinding position P1. Alternatively, the wafer W and the chuck stage 21 can be moved in a manner other than linear reciprocating motion.

[0060] Figure 13This is a simplified top view schematically illustrating an example of a grinding apparatus 10 equipped with an indexing table 71. The grinding apparatus 10 is configured to rotate the indexing table 71 around its table center O4. In one example, the grinding apparatus 10 is configured to rotate the indexing table 71 about a rotation axis connected to a motor provided in a table transport mechanism (not shown). Three chuck tables 21 are respectively provided on the indexing table 71 to hold and rotate the wafer W. The three chuck tables 21 are arranged such that the distance from the table center O4 to the table center O1 of each chuck table 21 is equal and they are evenly spaced in the circumference of the indexing table 71. The imaginary line L1 (the movement trajectory of the table center O1) traversed by the table center O1 of the chuck table 21, which moves due to the rotation of the indexing table 71, is a circle centered on the table center O4 of the indexing table 71. The imaginary line L1 is also the imaginary line through which the wafer center O2 of the wafer W on each chuck stage 21 passes. The indexing stage 71 uses the driving force of the motor of the stage transport mechanism to rotate and move the wafer W and the chuck stage 21 sequentially to the non-grinding position P2, the rough grinding position P1A, the fine grinding position P1B, and the non-grinding position P2. In addition, the rough grinding position P1A and the fine grinding position P1B are respectively provided with a processing part 14 having a grinding stone 41 for grinding the surface of the wafer W.

[0061] In the control unit 16, at least one of the following is stored, corresponding to the three chuck stages 21 provided on the indexing stage 71: the variation characteristics of the inclination of the grinding wheel rotation axis O3 of the grinding wheel 41 relative to the grinding load when the grinding wheel 41 is used to grind the chuck stage 21, and the variation characteristics of the inclination of the stage rotation axis O1 of the chuck stage 21 relative to the grinding load. Based on the variation characteristics corresponding to each chuck stage 21, the control unit 16 controls the relative inclination of the grinding wheel rotation axis O3 of the grinding wheel 41 and the stage rotation axis O1 of the chuck stage 21 according to the grinding load when the wafer W is ground with the grinding wheel 41. In this way, the uniformity of the thickness of the wafer W can also be improved in the grinding apparatus 10 including the indexing stage 71.

[0062] like Figure 14 As shown, the grinding device 10 can also be configured to adjust the inclination of the grinding stone rotation axis O3 of the grinding stone 41. Alternatively, the grinding device 10 can also be configured to adjust the inclination of both the table rotation axis O1 of the chuck table 21 and the grinding stone rotation axis O3 of the grinding stone 41.

[0063] The control unit 16 can also control the tilt of the table rotation axis O1 of the chuck table 21 based on the variation characteristic 62a of the tilt of the grinding wheel rotation axis O3 of the grinding wheel 41 relative to the grinding load when grinding the chuck table 21 with the grinding wheel 41, according to the grinding load when grinding the wafer W with the grinding wheel 41. This can also improve the uniformity of the thickness of the wafer W.

[0064] The control unit 16 can also control the tilt of the grinding wheel rotation axis O3 of the grinding wheel 41 and the tilt of the table rotation axis O1 of the chuck table 21 based on the variation characteristic 62a of the tilt of the grinding wheel rotation axis O3 of the grinding wheel 41 relative to the grinding load when grinding the chuck table 21 with the grinding wheel 41, according to the grinding load when grinding the wafer W with the grinding wheel 41. This can also improve the uniformity of the thickness of the wafer W.

[0065] The control unit 16 can also control the tilt of the table rotation axis O1 of the chuck table 21 based on the variation characteristic 62b of the tilt of the table rotation axis O1 of the chuck table 21 relative to the grinding load when grinding the chuck table 21 with the grinding stone 41, according to the grinding load when grinding the wafer W with the grinding stone 41. This can also improve the uniformity of the thickness of the wafer W.

[0066] The control unit 16 can also control the tilt of the grinding wheel rotation axis O3 of the grinding wheel 41 and the tilt of the table rotation axis O1 of the chuck table 21 based on the variation characteristics 62b of the tilt of the table rotation axis O1 of the chuck table 21 relative to the grinding load when grinding the chuck table 21 with the grinding wheel 41, according to the grinding load when grinding the wafer W with the grinding wheel 41. This can also improve the uniformity of the thickness of the wafer W.

[0067] The control unit 16 can also control the relative tilt of the grinding wheel rotation axis O3 of the grinding wheel 41 and the table rotation axis O1 of the chuck table 21 based on the variation characteristics 62a and 62b, according to the grinding load when grinding the wafer W with the grinding wheel 41. This can also improve the uniformity of the thickness of the wafer W.

[0068] The variable characteristics stored in the control unit 16 may also include the inclination of the grinding wheel rotation axis O3 of the grinding wheel 41 and the inclination of the table rotation axis O1 of the chuck table 21 relative to the grinding load.

[0069] As a variable characteristic, the control unit 16 can store at least one of the variable characteristics of the tilt angle of the grinding wheel rotation axis O3 of the grinding wheel 41 relative to the grinding load when grinding the wafer W with the grinding wheel 41, and the variable characteristics of the tilt angle of the table rotation axis O1 of the chuck table 21 relative to the grinding load. Alternatively, the control unit 16 can store both the variable characteristics of the tilt angle of the grinding wheel rotation axis O3 of the grinding wheel 41 and the tilt angle of the table rotation axis O1 of the chuck table 21 relative to the grinding load when grinding the wafer W with the grinding wheel 41. Based on these variable characteristics, the control unit 16 can control at least one of the tilt angle of the grinding wheel rotation axis O3 of the grinding wheel 41 and the tilt angle of the table rotation axis O1 of the chuck table 21 according to the grinding load when grinding the wafer W with the grinding wheel 41.

[0070] Furthermore, this disclosure is not limited to the above-described embodiments and variations, and various modifications can be made to implement it without departing from the spirit of this disclosure. These modifications are all included in the technical concept of this disclosure. Additionally, unless otherwise specified in the specification, the constituent elements of this disclosure are not limited to one and multiple elements may exist. Explanation of reference numerals in the attached figures

[0071] 10…grinding apparatus, 11…housing, 12…holding part, 13…moving part, 13a…moving worktable, 13b…guide part, 13c…drive part, 14…processing part, 14a…base component, 15…measuring part, 16…control part, 21…chuck worktable, 21a…wafer holding surface, 22…support part, 23…tilting part, 24…adsorbent, 31…tilting worktable, 32…fixed support part, 33…movable support part, 34…bolt, 35…nut, 36…tilting ball screw, 37…tilting motor, 38…scale, 41…grinding stone, 42…grinding wheel, 42a…grinding stone holding surface, 43…spindle, 43a…motor, 44…spindle feed part, 45…column 46…Connecting part, 46a…Guide rail, 46b…Base part, 47…Drive part, 47a…Motor, 51…Shape measuring part, 51a…Sensor head, 51b…Sensor head, 55…Load sensor, 61a, 61b…Detection part, 62a, 62b…Variable characteristics, 63a, 63b…Characteristic points, 71…Indexing stage, A1…Grinding area, L1…Imaginary line, O1…Stage rotation axis (stage center), O2…Wafer rotation axis (wafer center), O3…Grinding stone rotation axis, O4…Stage center, P1…Grinding position, P1A…Rough grinding position, P1B…Fine grinding position, P2…Non-grinding position, W…Wa…Upper surface, Wb…Lower surface.

Claims

1. A grinding apparatus, comprising: The chuck stage holds the wafer in a position to rotate; The processing unit has a grinding stone, which is used to process the wafer by rotating the grinding stone; as well as The control unit controls the relative tilt between the rotation axis of the grinding stone and the rotation axis of the chuck table. The control unit controls the relative tilt of the grinding stone's rotation axis and the chuck stage's rotation axis based on at least one of the variation characteristics of the tilt of the grinding stone's rotation axis relative to the grinding load when grinding the wafer with the grinding stone.

2. The grinding apparatus according to claim 1, wherein, The control unit controls the tilt of the grinding stone's rotation axis based on the variation characteristics of the tilt of the grinding stone's rotation axis relative to the grinding load, according to the grinding load when the wafer is ground with the grinding stone.

3. The grinding apparatus according to claim 1, wherein, The control unit controls the tilt of the chuck stage's rotation axis based on the variation characteristics of the tilt of the grinding stone's rotation axis relative to the grinding load, according to the grinding load when grinding the wafer with the grinding stone.

4. The grinding apparatus according to claim 1, wherein, The control unit controls the tilt of the grinding stone's rotation axis and the tilt of the chuck stage's rotation axis based on the variation characteristics of the tilt of the grinding stone's rotation axis relative to the grinding load, according to the grinding load when grinding the wafer with the grinding stone.

5. The grinding apparatus according to claim 1, wherein, The control unit controls the tilt of the grinding wheel's rotation axis based on the variation characteristics of the tilt of the chuck stage's rotation axis relative to the grinding load, according to the grinding load when grinding the wafer with the grinding wheel.

6. The grinding apparatus according to claim 1, wherein, The control unit controls the tilt of the chuck stage's rotation axis based on the variation characteristics of the tilt of the chuck stage's rotation axis relative to the grinding load, according to the grinding load when grinding the wafer with the grinding stone.

7. The grinding apparatus according to claim 1, wherein, The control unit controls the tilt of the grinding stone's rotation axis and the tilt of the chuck stage's rotation axis based on the variation characteristics of the tilt of the chuck stage's rotation axis relative to the grinding load, according to the grinding load when grinding the wafer with the grinding stone.

8. The grinding apparatus according to claim 1, wherein, The control unit controls the tilt of the grinding stone's rotation axis and the tilt of the chuck stage's rotation axis based on the grinding load when the wafer is being ground with the grinding stone, based on the variation characteristics of the tilt of the grinding stone's rotation axis relative to the grinding load and the variation characteristics of the tilt of the chuck stage's rotation axis relative to the grinding load.

9. The grinding apparatus according to claim 1, wherein, The grinding apparatus includes a shape measuring unit for measuring the shape of the wafer. The control unit controls the relative tilt of the grinding stone's rotation axis to the rotation axis of the chuck stage based on the grinding load and the shape of the wafer measured by the shape measuring unit.

10. The grinding apparatus according to any one of claims 2, 3, 4, and 8, wherein, The control unit has a data table to show the variation characteristics of the tilt of the rotation axis of the grinding stone relative to the grinding load. The data table is a table that associates multiple grinding loads with the normal direction of the grinding stone holding surface relative to the multiple grinding loads. The relative tilt of the rotation axis of the grinding stone and the rotation axis of the chuck table is controlled according to the normal direction relative to the grinding load.

11. The grinding apparatus according to any one of claims 5, 6, 7, and 8, wherein, The control unit has a data table to show the variation characteristics of the tilt of the chuck stage's rotation axis relative to the grinding load. The data table is a table that associates multiple grinding loads with the normal direction of the wafer holding surface for holding the wafer relative to the multiple grinding loads. The relative tilt of the grinding stone's rotation axis and the chuck stage's rotation axis is controlled according to the normal direction relative to the grinding load.

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