Measurement device, grinding system, and measurement method

Abstract

This measurement device measures the dimension of a dress board for use in dressing of a grinding tool. The measurement device comprises: a stage that holds the dress board; a reflector that is placed on the upper surface of the dress board held by the stage; an optical sensor that irradiates the upper surface of the reflector with light and receives light reflected by the upper surface of the reflector; and a support body that supports the reflector so as to be able to move up and down.

Description

MEASURING APPARATUS, GRINDING SYSTEM, AND MEASURING METHOD

[0001] The present disclosure relates to a measurement device, a grinding system, and a measurement method.

[0002] Patent Documents 1 and 2 describe measuring the thickness of a dress board used for dressing a grinding tool. The measuring devices described in Patent Documents 1 and 2 are contact type. However, Patent Document 2 describes that the measuring device may be a non-contact type.

[0003] Japanese Patent Publication No. 2022-032755 Japanese Patent Publication No. 2018-149621

[0004] One embodiment of the present disclosure provides a technique for improving the accuracy of measuring the dimensions of a dress board.

[0005] A measuring device according to an embodiment of the present disclosure measures the dimensions of a dress board used for dressing a grinding tool, and includes a stage for holding the dress board, a reflector placed on an upper surface of the dress board held by the stage, an optical sensor for irradiating light toward the upper surface of the reflector and receiving light reflected by the upper surface of the reflector, and a support for supporting the reflector so as to be movable up and down relative to the stage.

[0006] According to one embodiment of the present disclosure, the measurement accuracy of the dimensions of the dress board can be improved.

[0007] FIG. 1 is a plan view showing a grinding system according to one embodiment. FIG. 2 is a side view showing the grinding system shown in FIG. 1. FIG. 3 is a cross-sectional view showing an example of a drive unit. FIG. 4 is a diagram showing an example of a change in the height of a rotating unit over time. FIG. 5 is a cross-sectional view showing an example of dressing of a grinding tool. FIG. 6 is a plan view showing an example of a dress board. FIG. 7(A) is a cross-sectional view showing an example of a measuring device, showing an example of a standby position of a support, and FIG. 7(B) is a cross-sectional view showing an example of a measurement position of the support. FIG. 8(A) is a cross-sectional view showing an example of a reference height of the upper surface of a reflector, and FIG. 8(B) is a cross-sectional view showing another example of the reference height of the upper surface of a reflector.

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that in each drawing, the same or similar components are denoted by the same reference numerals, and descriptions thereof may be omitted. In each drawing, the X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other, the X-axis direction and the Y-axis direction are horizontal, and the Z-axis direction is vertical. The X-axis direction includes the positive X-axis direction and the negative X-axis direction that is opposite to the positive X-axis direction. The Y-axis direction includes the positive Y-axis direction and the negative Y-axis direction that is opposite to the positive Y-axis direction. The Z-axis direction includes the positive Z-axis direction and the negative Z-axis direction that is opposite to the positive Z-axis direction.

[0009] A grinding system 1 according to one embodiment will be described mainly with reference to Figures 1 and 2. As shown in Figure 1, the grinding system 1 includes a grinding apparatus 10, a measuring apparatus 20, a storage apparatus 30, and a transport apparatus 40. The grinding apparatus 10 grinds a substrate W by pressing a grinding tool T against the substrate W as shown in Figure 2. In this specification, grinding includes polishing. The measuring apparatus 20 measures the dimensions of a dress board B. The dress board B is used for dressing the grinding tool T. The storage apparatus 30 stores the dress board B. The transport apparatus 40 transports the substrate W or the dress board B. The transport apparatus 40 transports the dress board B between the storage apparatus 30, the measuring apparatus 20, and the grinding apparatus 10.

[0010] The grinding system 1 may include a first platform (not shown) or a second platform (not shown). The first platform receives a cassette containing a substrate W or a dress board B. The second platform receives a substrate W or a dress board B removed from the cassette. The transport device 40 may unload the substrate W or the dress board B from the first platform or the second platform. The transport device 40 may also load the substrate W or the dress board B onto the first platform or the second platform.

[0011] The grinding apparatus 10 includes, for example, four holders 11A to 11D, two drive units 12A to 12B, and a housing 13. The holders 11A to 11D hold the substrate W or the dress board B. Holding includes suction. The drive units 12A and 12B drive the grinding tool T. The housing 13 houses the holders 11A to 11D and the grinding tool T. The housing 13 prevents particles and mist generated during grinding from escaping to the outside. The housing 13 has a load / unload opening 13a. The substrate W or the dress board B is loaded from the outside of the housing 13 into the inside, or unloaded from the inside of the housing 13 to the outside, through the load / unload opening 13a.

[0012] The grinding apparatus 10 may include a nozzle 14 as shown in Fig. 2. The nozzle 14 is provided inside the housing 13. The nozzle 14 sprays gas from the nozzle 14 toward the opposite side of the housing 13 from the loading / unloading port 13a, forming an airflow along the underside of the substrate W or dress board B. The airflow removes the cleaning liquid or grinding liquid adhering to the underside of the substrate W or dress board B. This can prevent the cleaning liquid or grinding liquid from being carried out of the housing 13 together with the substrate W or dress board B.

[0013] The grinding device 10 may include a rotary table 15 as shown in FIG. 1. The rotary table 15 is provided inside the housing 13. The rotary table 15 is rotated around a rotation center line R1. The four holders 11A to 11D are provided at intervals around the rotation center line R1 of the rotary table 15 and are rotated together with the rotary table 15. Furthermore, the four holders 11A to 11D are rotated independently around their respective rotation center lines R2 (see FIG. 2).

[0014] The two holders 11A, 11C are arranged symmetrically about the rotation center line R1 of the turntable 15. Each holder 11A, 11C moves between a first load / unload position A3, where the transport device 40 loads or unloads the substrate W or the dress board B, and a first grinding position A1, where the drive unit 12A grinds the substrate W or the dress board B with the grinding tool T. The two holders 11A, 11C move between the first load / unload position A3 and the first grinding position A1 every time the turntable 15 rotates 180°. At the first grinding position A1, a nozzle 16 (see FIG. 2 ) supplies a grinding fluid such as water to the upper surface of the substrate W when the substrate W or the dress board B is ground. The nozzle 16 is provided inside the housing 13.

[0015] The other two holders 11B, 11D are arranged symmetrically about the rotation center line R1 of the turntable 15. Each holder 11B, 11D moves between a second load / unload position A0, where the transport device 40 loads or unloads the substrate W or the dress board B, and a second grinding position A2, where the drive unit 12B grinds the substrate W or the dress board B with the grinding tool T. The other two holders 11B, 11D move between the second load / unload position A0 and the second grinding position A2 every time the turntable 15 rotates 180°. At the second grinding position A2, as with the first grinding position A1, a nozzle (not shown) supplies a grinding fluid such as water to the upper surface of the substrate W when the substrate W or the dress board B is being ground.

[0016] When viewed from above, the first loading / unloading position A3, the second loading / unloading position A0, the first grinding position A1, and the second grinding position A2 are arranged in this order in a counterclockwise direction. In this case, when viewed from above, the holding portions 11A, 11B, 11C, and 11D are arranged in this order at 90° intervals in a counterclockwise direction.

[0017] The positions of the first loading / unloading position A3 and the second loading / unloading position A0 may be reversed, and the positions of the first grinding position A1 and the second grinding position A2 may also be reversed. That is, when viewed from above, the first loading / unloading position A3, the second loading / unloading position A0, the first grinding position A1, and the second grinding position A2 may be arranged in this order clockwise. In this case, when viewed from above, the holding units 11A, 11B, 11C, and 11D are arranged in this order clockwise at 90° intervals.

[0018] However, the number of holding units is not limited to four, and the number of driving units is not limited to two. Also, the rotary table 15 may be omitted. Instead of the rotary table 15, a slide table may be provided.

[0019] The measuring device 20 measures the dimensions of the dress board B. The dress board B is used to dress the grinding tool T. The dressing of the grinding tool T is performed by grinding the dress board B with the driving unit 12A or 12B using the grinding tool T while the holding unit 11A, 11B, 11C, or 11D holds the dress board B.

[0020] The measuring device 20 may be provided outside the housing 13 of the grinding device 10. In this case, the transport device 40 transports the measuring device 20 to the dress board B between the measuring device 20 and the grinding device 10. When the measuring device 20 is provided outside the housing 13 of the grinding device 10, it is possible to prevent the measuring device 20 from being contaminated by particles and mist generated during grinding.

[0021] The measuring device 20 may be provided inside the housing 13 of the grinding device 10. In this case, the holding units 11A, 11B, 11C, and 11D of the grinding device 10 may also serve as the stage 21 (see FIG. 7 ) of the measuring device 20. In this case, the measuring device 20 can also measure the dimensions of the substrate W (for example, the thickness of the substrate W).

[0022] The storage device 30 stores the dress board B. Similar to the measuring device 20, the storage device 30 may be provided outside the housing 13 of the grinding device 10. In this case, the transport device 40 transports the dress board B between the storage device 30 and the grinding device 10. When the storage device 30 is provided outside the housing 13 of the grinding device 10, it is possible to prevent the dress board B from being contaminated by particles and mist generated during grinding.

[0023] The storage device 30 may be provided separately from the measuring device 20. In this case, the transport device 40 transports the dress board B between the storage device 30 and the measuring device 20. When the storage device 30 stores multiple dress boards B, the measuring device 20 can measure the dimensions of the multiple dress boards B in sequence. Therefore, the number of measuring devices 20 can be reduced.

[0024] From the viewpoint of installation space, the measuring device 20 and the storage device 30 may be stacked vertically as shown in FIG.

[0025] The transport device 40 includes a transport arm 41 that transports the substrate W or the dress board B. The transport arm 41 includes a suction pad 42 that adsorbs the substrate W or the dress board B. The suction pad 42 is capable of moving horizontally (in both the X-axis direction and the Y-axis direction) and vertically, and of rotating about a vertical axis. The grinding system 1 may also include an inverting unit (not shown) that inverts the substrate W.

[0026] The grinding system 1 includes a control circuit 90. The control circuit 90 is, for example, a computer. The control circuit 90 includes an arithmetic unit 91 such as a CPU (Central Processing Unit) and a storage unit 92 such as a memory. The storage unit 92 stores programs that control various processes executed in the grinding system 1. The control circuit 90 controls the operation of the grinding system 1 by causing the arithmetic unit 91 to execute the programs stored in the storage unit 92. A lower-level control circuit that controls the operation of each device that makes up the grinding system 1 may be provided, and a higher-level control circuit that controls multiple lower-level control circuits may be provided. The control circuit 90 may be configured with the lower-level control circuit and the higher-level control circuit.

[0027] The program, i.e., a computer program product, may be supplied in a form recorded on a removable storage medium such as a memory card, an optical disk, or a hard disk drive (HDD). The control circuit 90 reads the program from the storage medium and stores it in the storage unit 92. The storage unit 92 includes a storage medium such as an HDD, a solid state drive (SDD), or an electronically erasable programmable read-only memory (EEPROM). The program may be written in advance to the storage medium of the storage unit 92. The control circuit 90 may also obtain the program distributed by a remote server device or the like via a network or other communication.

[0028] The control circuit 90 includes electronic circuits such as a CPU, a graphics processing unit (GPU), a field programmable gate array (FPGA), or an application specific integrated circuit (ASIC). The control circuit 90 executes various control operations described in this specification by executing instruction codes stored in a storage medium such as a memory, or by being a circuit designed for a specific application.

[0029] An example of the operation of the grinding system 1 shown in Figures 1 and 2 will be described. The following operation is performed under the control of the control circuit 90. First, the transport device 40 unloads the substrate W from the first or second platform, and transports the unloaded substrate W to a holder (e.g., holder 11C) located at the first load / unload position A3. The holder 11C holds the substrate W with the first main surface of the substrate W facing upward. Thereafter, the turntable 15 is rotated 180°, and the holder 11C is moved from the first load / unload position A3 to the first grinding position A1.

[0030] Next, the drive unit 12A drives the grinding tool T to grind the first main surface of the substrate W. Thereafter, the turntable 15 is rotated 180 degrees, and the holder 11C is moved from the first grinding position A1 to the first load / unload position A3. Subsequently, the transport device 40 receives the substrate W from the holder 11C located at the first load / unload position A3, and removes it from inside the housing 13 to the outside. Thereafter, the inversion unit inverts the substrate W upside down.

[0031] Next, the transport device 40 transports the substrate W to a holder (e.g., holder 11D) located at the second load / unload position A0. The holder 11D holds the substrate W with the second main surface of the substrate W facing upward. The second main surface faces opposite the first main surface. Thereafter, the turntable 15 is rotated 180°, and the holder 11D is moved from the second load / unload position A0 to the second grinding position A2.

[0032] Next, the drive unit 12B drives the grinding tool T to grind the second main surface of the substrate W. Thereafter, the turntable 15 is rotated 180 degrees, and the holder 11D is moved from the second grinding position A2 to the second load / unload position A0. Subsequently, the transport device 40 receives the substrate W from the holder 11D located at the second load / unload position A0, and unloads it from inside the housing 13 to the outside.

[0033] Here, the operation of the grinding system 1 has been described with a focus on one substrate W. The grinding system 1 may simultaneously perform multiple processes at multiple positions to improve throughput. For example, the grinding system 1 simultaneously grinds substrates W at each of the first grinding position A1 and the second grinding position A2. Meanwhile, the grinding system 1 performs, in this order, spray cleaning of the substrate W, measurement of the thickness distribution of the substrate W, unloading of the substrate W, cleaning of the holding surface (upper surface) of the holder 11A, 11B, 11C, or 11D, and loading of the substrate W, for example, at each of the first load / unload position A3 and the second load / unload position A0.

[0034] Thereafter, the grinding system 1 rotates the turntable 15 by 180°. Subsequently, the grinding system 1 simultaneously grinds the substrate W again at each of the first grinding position A1 and the second grinding position A2. Meanwhile, the grinding system 1 again performs spray cleaning of the substrate W, measurement of the thickness distribution of the substrate W, unloading the substrate W, cleaning the holding surface (upper surface) of the holder 11A, 11B, 11C or 11D, and loading the substrate W, in this order, at each of the first load / unload position A3 and the second load / unload position A0.

[0035] An example of the grinding apparatus 10 will be described again with reference to Fig. 3. The grinding apparatus 10 grinds the substrate W by pressing the grinding tool T against the substrate W. The grinding tool T includes, for example, a disk-shaped grinding wheel T1 and a plurality of grinding stones T2 arranged in a ring shape on the lower surface of the grinding wheel T1. The grinding stones T2 grind the substrate W.

[0036] The grinding apparatus 10 includes a holding unit 11A. The holding unit 11A has a holding surface 111 on its upper surface that holds the substrate W. The holding unit 11A holds the substrate W from the side opposite to the grinding tool T (i.e., from below). The holding unit 11A is, for example, a vacuum chuck, and includes a porous body 112 that forms the holding surface 111, and a base 113 in which the porous body 112 is embedded. The holding surface 111 may be flat as shown in FIG. 3, or may have a conical surface to adjust the thickness distribution of the substrate W. Note that the configurations of the holding units 11B to 11D shown in FIG. 1 are similar to the configuration of the holding unit 11A shown in FIG. 3, and therefore description thereof will be omitted.

[0037] The grinding apparatus 10 includes a second rotating unit 17. The second rotating unit 17 rotates the holding unit 11A. The second rotating unit 17 has, for example, a rotation motor 171 and a vertical rotation shaft 172 that is rotated by the rotation motor 171. The holding unit 11A is provided at the upper end of the rotation shaft 172. The rotation motor 171 rotates the holding unit 11A together with the rotation shaft 172. The rotation shaft 172 may be inclined to adjust the thickness distribution of the substrate W.

[0038] The grinding device 10 includes a drive unit 12A. The drive unit 12A drives the grinding tool T. The drive unit 12A has, for example, a rotation unit 121 and an elevation unit 125. The rotation unit 121 holds and rotates the grinding tool T. The elevation unit 125 elevates the grinding tool T together with the rotation unit 121. Note that the configuration of the drive unit 12B shown in FIG. 1 is similar to the configuration of the drive unit 12A shown in FIG. 3, and therefore description thereof will be omitted.

[0039] The rotating unit 121 has, for example, a rotary motor 122, a vertical spindle shaft 123 rotated by the rotary motor 122, and a flange 124 provided at the lower end of the spindle shaft 123. The flange 124 is disposed horizontally, and a grinding tool T is attached to its lower surface. The rotary motor 122 rotates the spindle shaft 123, thereby rotating the grinding tool T attached to the lower surface of the flange 124.

[0040] The lifting unit 125 has, for example, a vertical Z-axis guide 126, a Z-axis slider 127 that moves along the Z-axis guide 126, and an elevator motor 128 that moves the Z-axis slider 127. The rotary motor 122 is fixed to the Z-axis slider 127 via a motor holder 129. The lifting unit 125 has a ball screw (not shown) that converts the rotational motion of the elevator motor 128 into linear motion of the Z-axis slider 127.

[0041] The grinding apparatus 10 includes a first measuring unit 18. The first measuring unit 18 measures the thickness of the substrate W held by the holder 11A. The first measuring unit 18 has, for example, a contact-type first gauge sensor 181 that measures the height of the upper surface of the substrate W, and a contact-type second gauge sensor 182 that measures the height of the holding surface 111 of the holder 11A. The difference in height between the upper surface of the substrate W and the holding surface 111 of the holder 11A is the thickness of the substrate W. The first measuring unit 18 transmits a signal indicative of the thickness of the substrate W to the control circuit 90.

[0042] Although the first measuring unit 18 is of a contact type in this embodiment, it may be of a non-contact type. The non-contact type first measuring unit 18 has, for example, a laser displacement meter. The laser displacement meter irradiates light from above the substrate W and receives light reflected from the upper surface of the substrate W and light reflected from the lower surface of the substrate W, thereby measuring the height difference between the upper and lower surfaces of the substrate W, i.e., the thickness of the substrate W. The laser displacement meter is, for example, of a spectral interference type or a confocal type.

[0043] The grinding device 10 includes a second measuring unit 19. The second measuring unit 19 measures the height of the rotating unit 121. The height of the rotating unit 121 is the position of the rotating unit 121 in the Z-axis direction. The second measuring unit 19 is, for example, a rotary encoder, and measures the height of the rotating unit 121 by measuring the rotation of the lift motor 128. The second measuring unit 19 transmits a signal indicating the height of the rotating unit 121 to the control circuit 90. The height of the rotating unit 121 can be rephrased as the height of the grinding tool T.

[0044] It should be noted that second measurement unit 19 is not limited to a rotary encoder. Second measurement unit 19 may be a linear encoder, and may have a scale installed along Z-axis guide 126 and a read head mounted on Z-axis slider 127. The read head reads the graduations on the scale.

[0045] An example of the change in height of the rotating unit 121 over time will be described with reference to Figure 4. The height of the rotating unit 121 is controlled by the control circuit 90. The control circuit 90 starts lowering the rotating unit 121 at time t0. The control circuit 90 lowers the rotating unit 121 from the standby position Z0 to the air cut position Zair at a first speed V1. At this time, the control circuit 90 rotates the grinding tool T at a preset rotation speed. The control circuit 90 may also rotate the substrate W together with the holder 11A at a preset rotation speed. Note that the rotation start time of at least one of the grinding tool T and the substrate W may be time t1, which will be described later, instead of time t0.

[0046] When the second measurement unit 19 measures that the rotating unit 121 has reached the air-cut position Zair at time t1, the control circuit 90 decelerates the descending speed of the rotating unit 121 from the first speed V1 to a second speed V2 (V2<V1) that is smaller than the first speed V1. The air-cut position Zair is a position where the descending speed of the rotating unit 121 is decelerated just before the grinding wheel T2 hits the substrate W. The air-cut position Zair is set to a position shifted upward from the setup position Zset by a set amount.

[0047] The setup position Zset is a reference position when setting the air-cut position Zair. The setup position Zset is the height of the rotating part 121 at which it is estimated that the grinding wheel T2 will come into contact with the holding surface 111 of the holder 11A. The grinding wheel T2 wears out during grinding of the substrate W. The setup position Zset is the height of the rotating part 121 at which it is estimated that the grinding wheel T2, which has the same thickness as that of the substrate W immediately before being ground, will come into contact with the holding surface 111 of the holder 11A.

[0048] As described above, the air cut position Zair is set at a position shifted upward from the setup position Zset by a set amount. The difference in elevation between the setup position Zset and the air cut position Zair is equal to the sum of the thickness of the substrate W before grinding and the set value of the air cut amount ΔZ. The air cut amount ΔZ is the size of the gap formed between the grinding tool T and the substrate W at time t1.

[0049] As described above, the control circuit 90 lowers the rotating part 121 at high speed from time t0 to time t1, thereby preventing a decrease in throughput. Furthermore, the control circuit 90 lowers the rotating part 121 at low speed after time t1, thereby reducing the impact when the grinding wheel T2 contacts the substrate W and preventing damage to the substrate W and the grinding tool T. The grinding wheel T2 contacts the substrate W at time t2. Time t2 can be detected from the load current (or torque) of the rotary motor 122.

[0050] The control circuit 90 continues to lower the rotating part 121 even after time t2. The lower surface of the grinding wheel T2 is pressed against the upper surface of the substrate W, grinding the substrate W. In this embodiment, the control circuit 90 sets the lowering speed of the rotating part 121 to the second speed V2 even after time t2, but the speed may be further reduced to a third speed that is lower than the second speed V2.

[0051] When the first measuring unit 18 measures that the thickness of the substrate W has reached the set value at time t3, the control circuit 90 stops the lowering of the rotating unit 121. Thereafter, the control circuit 90 may rotate the grinding tool T and the substrate W for a set time Δt while stopping the raising and lowering of the rotating unit 121.

[0052] When the elapsed time from time t3 reaches the set time Δt at time t4, the control circuit 90 starts raising the rotating part 121. Note that the control circuit 90 may also start raising the rotating part 121 at time t3. The control circuit 90 raises the rotating part 121 to the standby position Z0. After the grinding tool T and the substrate W are separated, the control circuit 90 stops the rotation of the grinding tool T and the rotation of the holding part 11A.

[0053] Thereafter, while the rotating part 121 is waiting at the waiting position Z0, the substrate W is replaced, the ground substrate W is unloaded, and the unground substrate W is loaded in. The waiting position Z0 is set at a position above the air cut position Zair so that the grinding tool T does not interfere with the loading and unloading of the substrate W. After the substrate W is replaced, grinding of the substrate W is performed again.

[0054] The dress board B is ground in the same manner as the substrates W are ground. The dress board B may be ground between the grinding of the kth substrate W and the grinding of the (k+1)th substrate W. The setup position Zset when grinding the dress board B is determined from the thickness of the substrate W at the completion of grinding of the kth substrate W and the height of the rotating part 121 at the completion of grinding of the kth substrate W. The completion of grinding of the substrate W occurs, for example, when the rotating part 121 starts to rise after it has descended. The setup position Zset when grinding the (k+1)th substrate W is determined from the thickness of the dress board B at the completion of grinding of the dress board B and the height of the rotating part 121 at the completion of grinding of the dress board B. The completion of grinding of the dress board B occurs, for example, when the rotating part 121 starts to rise after it has descended.

[0055] An example of dressing of the grinding tool T will be described with reference to Figures 5 and 6. When grinding of the substrate W is repeatedly performed, the grinding tool T may become dull. Therefore, the grinding tool T is periodically dressed. Dressing of the grinding tool T involves the dressing board B scraping off the surface of the grinding tool T to restore the sharpness of the grinding tool T. Dressing of the grinding tool T is performed by the drive unit 12A or 12B grinding the dressing board B with the grinding tool T while the holding unit 11A, 11B, 11C or 11D holds the dressing board B.

[0056] The dressing board B has, for example, a support plate B1 and a dressing grindstone B2. The support plate B1 supports the dressing grindstone B2. The support plate B1 preferably has a diameter equivalent to that of the substrate W so that it can be easily held by the holder 11A, 11B, 11C, or 11D. The dressing grindstone B2 rubs against the grinding tool T (more specifically, the grinding wheel T2). The dressing grindstone B2 is fixed to the center of the upper surface of the support plate B1 with an adhesive or the like.

[0057] The support plate B1 is, for example, a resin plate. The dressing wheel B2 is, for example, a large number of abrasive grains bound together with a binder. The grain size of the abrasive grains constituting the dressing wheel B2 is set according to the grain size of the abrasive grains constituting the grinding wheel T2. Multiple dressing boards B with different grain sizes of the abrasive grains of the dressing wheel B2 may be prepared. Note that the dressing board B may have any general configuration and is not limited to the configuration shown in Figures 5 and 6.

[0058] The dressing board B can also be used for truing the grinding tool T. Truing the grinding tool T involves the dressing board B aligning the height of the cutting edge of the grinding tool T, thereby improving the grinding accuracy of the substrate W. Truing the grinding tool T is performed in the same manner as dressing the grinding tool T, by having the driving unit 12A or 12B grind the dressing board B with the grinding tool T while the holding unit 11A, 11B, 11C or 11D holds the dressing board B.

[0059] Incidentally, as the number of times the dress board B is used increases, the thickness of the dress board B (more specifically, the dress grindstone B2) becomes thinner. Therefore, the measuring device 20 may measure the thickness of the dress board B or the thickness of the dress grindstone B2. The thickness of the dress board B or the thickness of the dress grindstone B2 is used to manage the timing of replacing the dress board B. The thickness of the dress board B or the thickness of the dress grindstone B2 may also be used to set the setup position Zset or the air cut position Zair.

[0060] 7 and 8, an example of the measuring device 20 will be described. The measuring device 20 includes a stage 21, a reflector 22, an optical sensor 23, and a support 24. The stage 21 holds a dress board B. The reflector 22 is placed on the upper surface of the dress board B held by the stage 21. The optical sensor 23 irradiates light toward the upper surface of the reflector 22 and receives light reflected by the upper surface of the reflector 22. The support 24 supports the reflector 22 so that it can be raised and lowered freely.

[0061] The reflector 22 can be raised and lowered freely relative to the support 24. The reflector 22 can be raised and lowered freely as long as its distance from the stage 21 is within a desired range (a range in which the thickness of the dress board B can be measured). If the reflector 22 can be raised and lowered freely relative to the support 24, the force pressing the reflector 22 against the upper surface of the dress board B is only the weight of the reflector 22. Therefore, deformation of the reflector 22 and the dress board B can be suppressed, and measurement accuracy can be improved.

[0062] The stage 21 holds the dressing board B with the dressing wheel B2 facing upward. The dressing wheel B2 is made of a large number of abrasive grains bound together with a binder. Therefore, the upper surface of the dressing wheel B2 has irregularities. Contamination can get into the recesses of the irregularities. The contamination is, for example, particles generated when grinding the substrate W. When the upper surface of the dressing wheel B2 becomes contaminated, the color of the upper surface of the dressing wheel B2 changes. The change in color alters the light reflection characteristics.

[0063] The optical sensor 23 receives light reflected by the upper surface of the reflector 22, not light reflected by the upper surface of the dress board B. Unlike the dress board B, the reflector 22 does not come into contact with the grinding tool T. Therefore, dirt is not transferred from the grinding tool T to the reflector 22. Therefore, the color of the reflector 22 does not change. The reflector 22 can maintain its light reflection properties for a long period of time. This improves the measurement accuracy of the dimensions of the dress board B.

[0064] The surface roughness of the upper surface of the reflector 22 is preferably smaller than the surface roughness of the upper surface of the dressing board B (more specifically, the dressing grindstone B2). The surface roughness is expressed, for example, by the arithmetic mean roughness Ra as defined in JIS B0601:2013. By receiving light reflected by the upper surface of the reflector 22, which has a smaller surface roughness, rather than light reflected by the upper surface of the dressing board B, which has a larger surface roughness, the effects of diffuse reflection of light can be reduced.

[0065] Unlike a contact-type gauge sensor, the optical sensor 23 does not come into contact with either the dress board B or the reflector 22. Therefore, the optical sensor 23 is not pushed back by either the dress board B or the reflector 22, and no positional deviation of the optical sensor 23 occurs. This improves the measurement accuracy of the dimensions of the dress board B.

[0066] When the probe of the contact-type gauge sensor comes into contact with the upper surface of the dressing grinding wheel B2, the height of the probe may fluctuate due to unevenness on the upper surface of the dressing grinding wheel B2. Unlike the contact-type gauge sensor, the optical sensor 23 does not come into contact with the upper surface of the dressing grinding wheel B2. Therefore, the optical sensor 23 is not affected by unevenness on the upper surface of the dressing grinding wheel B2. This improves measurement accuracy.

[0067] The optical sensor 23 is, for example, a displacement sensor that measures the thickness of the dress board B or the dress grindstone B2 by measuring the height of the upper surface of the reflector 22. From the viewpoint of cost reduction, the displacement sensor is preferably, for example, a triangulation type. However, the type of the displacement sensor is not limited to the triangulation type. For example, the displacement sensor may be a spectral interference type or a confocal type.

[0068] The thickness of the dress board B may be measured using the height of the upper surface of the reflector 22 when the lower surface of the reflector 22 is in contact with the upper surface of the stage 21 as a reference height, as shown in Figure 8(A). The amount of displacement from the reference height is the thickness of the dress board B. The thickness of the dress grindstone B2 may be measured using the height of the upper surface of the reflector 22 when the lower surface of the reflector 22 is in contact with the upper surface of the support plate B1 as a reference height, as shown in Figure 8(B). The amount of displacement from the reference height is the thickness of the dress grindstone B2.

[0069] The measuring device 20 may include an elevator mechanism 25. The elevator mechanism 25 raises and lowers the support 24 relative to the stage 21 between a standby position and a measurement position. The standby position is a position where the support 24 supports the reflector 22 from below and the reflector 22 is separated from the upper surface of the dress board B, as shown in FIG. 7A. The standby position is a position above the measurement position. The measurement position is a position where the reflector 22 abuts on the upper surface of the dress board B and the support 24 is separated downward from the reflector 22, as shown in FIG. 7B.

[0070] The lifting mechanism 25 is a lifter. For example, the lifting mechanism 25 includes a cylinder. The support 24 is raised and lowered by the extension and contraction of the cylinder. Alternatively, the lifting mechanism 25 includes a slider, a guide that guides the slider in the vertical direction, and a motor that moves the slider. The support 24 is raised and lowered together with the slider.

[0071] When the lifting mechanism 25 raises the support 24 to the standby position, the reflector 22 moves away from the upper surface of the dress board B, making it possible to carry the dress board B into and out of the stage 21. When the lifting mechanism 25 lowers the support 24 to the measurement position, the reflector 22 comes into contact with the upper surface of the dress board B, making it possible to measure the thickness of the dress board B or the thickness of the dress grindstone B2.

[0072] When the support 24 is in the measurement position, the support 24 is spaced downward from the reflector 22. Therefore, no external force from the lifting mechanism 25 acts on the reflector 22. The only force pressing the reflector 22 against the upper surface of the dress board B is the weight of the reflector 22. Therefore, deformation of the reflector 22 and the dress board B can be suppressed, and measurement accuracy can be improved.

[0073] The lifting mechanism 25 preferably raises and lowers the support 24 relative to the optical sensor 23. The support 24 can be raised and lowered while the optical sensor 23 is stopped, and thus the reflector 22 can be raised and lowered. The thickness of the dress board B or the dress grindstone B2 can be measured solely from the amount of displacement in height of the reflector 22.

[0074] Although not shown, the lifting mechanism 25 may lift and lower the optical sensor 23 and the support 24 together. In this case, the thickness of the dressing board B or the dressing grindstone B2 can be measured from the amount of displacement in height of the optical sensor 23 and the amount of displacement in height of the reflector 22, but the calculation of the thickness is complicated. In this case, the lifting mechanism 25 may be part of the moving mechanism 26 described later.

[0075] The measuring device 20 may include a movement mechanism 26. The movement mechanism 26 moves the optical sensor 23 and the support 24 together in the horizontal and vertical directions. This allows the optical sensor 23 and the support 24 to be retracted from the carry-in / out path of the transport device 40, thereby simplifying the operation of the transport device 40 to carry in and out the dress board B. The movement mechanism 26 may include a horizontal movement mechanism and a vertical movement mechanism.

[0076] For example, the horizontal movement mechanism may include a cylinder. The optical sensor 23 moves horizontally by extension and contraction of the cylinder. Alternatively, the horizontal movement mechanism may include a slider, a guide that guides the slider horizontally, and a motor that moves the slider. The optical sensor 23 moves horizontally together with the slider.

[0077] For example, the vertical movement mechanism may include a cylinder. The optical sensor 23 moves vertically by extension and contraction of the cylinder. Alternatively, the vertical movement mechanism may include a slider, a guide that guides the slider vertically, and a motor that moves the slider. The optical sensor 23 moves vertically together with the slider.

[0078] Measuring device 20 may include both lifting mechanism 25 and moving mechanism 26, in which case it may also include holder 27. Holder 27 holds optical sensor 23 and lifting mechanism 25. Moving mechanism 26 moves holder 27 in the horizontal and vertical directions, thereby moving optical sensor 23 and lifting mechanism 25 together in the horizontal and vertical directions.

[0079] The reflector 22 has, for example, a vertical shaft portion 221 and a flange portion 222 provided on the upper end of the shaft portion 221. The support body 24 has an insertion hole 241 through which the shaft portion 221 is inserted. The length of the insertion hole 241 is shorter than the length of the shaft portion 221. The diameter of the insertion hole 241 is larger than the diameter of the shaft portion 221 and smaller than the diameter of the flange portion 222. The insertion hole 241 allows the shaft portion 221 to move up and down, and restricts the descent of the flange portion 222.

[0080] The support body 24 may have an accommodation hole 242 above the insertion hole 241 that accommodates at least a portion of the flange portion 222. The diameter of the accommodation hole 242 is larger than the diameter of the flange portion 222. Therefore, the diameter of the accommodation hole 242 is larger than the diameter of the insertion hole 241. By accommodating at least a portion of the flange portion 222 in the accommodation hole 242, the posture of the shaft portion 221 is stabilized.

[0081] The lifting mechanism 25 raises and lowers the support 24 relative to the stage 21 between a standby position and a measurement position. The standby position is a position where the support 24 contacts the lower surface of the flange portion 222 and the shaft portion 221 is separated from the upper surface of the dress board B, as shown in FIG. 7A. The standby position is a position above the measurement position. The measurement position is a position where the shaft portion 221 contacts the upper surface of the dress board B and the support 24 is separated from the lower surface of the flange portion 222, as shown in FIG. 7B.

[0082] Although the embodiments of the measuring device, grinding system, and measuring method according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure.

[0083] This application claims priority based on Japanese Patent Application No. 2024-126002 filed with the Japan Patent Office on August 1, 2024, the entire contents of which are incorporated herein by reference.

[0084] REFERENCE SIGNS LIST 1 Grinding system 20 Measuring device 21 Stage 22 Reflector 23 Optical sensor 24 Support B Dress board T Grinding tool W Substrate

Claims

A measuring device for measuring dimensions of a dressing board used for dressing a grinding tool, comprising: a stage for holding the dress board; a reflector placed on the upper surface of the dress board held by the stage; an optical sensor that irradiates light toward an upper surface of the reflector and receives light reflected by the upper surface of the reflector; a support that supports the reflector so that it can be raised and lowered; A measuring device comprising: 　 the reflector has a vertical shaft portion and a flange portion provided at an upper end of the shaft portion, the support body has an insertion hole through which the shaft portion is inserted, The measuring device according to claim 1 , wherein the diameter of the insertion hole is larger than the diameter of the shaft portion and smaller than the diameter of the flange portion. 　 the support body has an accommodation hole above the insertion hole that accommodates at least a part of the flange portion, The measuring device according to claim 2 , wherein the diameter of the receiving hole is larger than the diameter of the flange portion.

3. The measuring device according to claim 2, further comprising an elevation mechanism that raises and lowers the support relative to the stage between a standby position in which the support contacts the underside of the flange portion and the shaft portion is spaced from the upper surface of the dress board, and a measurement position in which the shaft portion contacts the upper surface of the dress board and the support is spaced from the underside of the flange portion.

2. The measuring device according to claim 1, further comprising an elevation mechanism that raises and lowers the support relative to the stage between a standby position in which the support supports the reflector from below and the reflector is separated from the upper surface of the dress board, and a measurement position in which the reflector abuts the upper surface of the dress board and the support is separated downward from the reflector. 　 The measuring device according to claim 1 , wherein the optical sensor is a displacement sensor that measures the height of the upper surface of the reflector to thereby measure the thickness of the dress board. 　 The dressing board has a dressing stone that rubs against the grinding tool and a support plate that supports the dressing stone, The measuring device according to claim 1 , wherein the stage holds the dressing board with the dressing grindstone facing upward. 　 The measuring device according to claim 7 , wherein the optical sensor is a displacement sensor that measures the height of the upper surface of the reflector to thereby measure the thickness of the dressing grindstone.

9. A grinding system comprising: the measuring device according to claim 1; and a grinding device that grinds the substrate by pressing the grinding tool against the substrate. 　 the grinding apparatus includes a holding unit that holds the substrate or the dress board, a drive unit that drives the grinding tool, and a housing that houses the holding unit and the grinding tool therein; the measuring device is provided outside the housing, The grinding system according to claim 9 , further comprising a transport device that transports the dress board between the measuring device and the grinding device. 　 a storage device for storing the dress board, separate from the measuring device; The grinding system according to claim 10 , wherein the transport device transports the dress board between the storage device and the measuring device. 　 A measuring method comprising measuring dimensions of the dress board using the measuring device according to any one of claims 1 to 8.

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