Grinding device

Abstract

To provide a grinding device, which can prevent a dress grindstone not corresponding to a type of a grinding grindstone from being used for dressing.SOLUTION: It can be discriminated whether a dresser board held by a holding surface is a first dresser board 11 or a second dresser board 12, by measuring height of the boards while setting a measurement point of an upper height measurement instrument 61 as a first position 611, which can determine whether the held dresser board corresponds to a type of a grinding grindstone. This can prevent a dress grindstone not corresponding to the type of the grinding grindstone from being used for dressing.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a grinding apparatus for grinding a workpiece held on a chuck table using a grinding wheel.

Background Art

[0002] In a grinding apparatus for grinding a wafer held on the holding surface of a chuck table by bringing the lower surface of a grinding wheel into contact with the wafer, when the grinding wheel is replaced, in order to flatten the lower surface of the grinding wheel, a dresser board provided with a dressing wheel is held on the holding surface of the chuck table, and dressing is performed by bringing the lower surface of the grinding wheel into contact with the dressing wheel. Here, the dresser board includes a disk that covers the entire holding surface, and the dressing wheel is disposed on the upper surface of the disk (see, for example, Patent Document 1).

[0003] Also, when machining chips adhere to the lower surface of the grinding wheel by grinding a workpiece made of a soft material using the grinding wheel, the dresser board is held on the holding surface and the lower surface of the grinding wheel is brought into contact with the dressing wheel to remove the machining chips adhering to the lower surface of the grinding wheel.

[0004] There are a rough grinding wheel and a finish grinding wheel for the grinding wheel, and there are also those formed with abrasive grains of various sizes for the rough grinding wheel and the finish grinding wheel. Therefore, it is necessary to use a dressing wheel formed with abrasive grains of a size corresponding to the type of grinding wheel during dressing.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Therefore, if dressing is accidentally performed using a dressing stone that does not correspond to the grinding wheel, the workpiece ground using the grinding wheel may not be finished to the desired surface. For example, if the dressing of a finish grinding wheel is performed using a dressing stone for a rough grinding wheel, the lower surface of the finish grinding wheel becomes rough, and a groove pattern like a scratch is formed on the surface to be ground of the wafer ground by the lower surface of the grinding wheel. Also, if the dressing of a rough grinding wheel is accidentally performed using a dressing stone for finish grinding, problems such as clogging occur due to the dressing stone abrasive grains and the like adhering to the lower surface of the rough grinding wheel, making it impossible to grind. Such problems occur because the operator fails to notice the mistake of the dresser board when holding the dresser board on the holding surface of the chuck table.

[0007] The present invention is conceived in view of such problems, and aims to prevent dressing using a dressing stone that does not correspond to the type of grinding wheel in a grinding apparatus.

Means for Solving the Problem

[0008] The present invention provides a grinding apparatus comprising: a chuck table that holds a workpiece or a dresser board on a holding surface; a grinding mechanism that grinds the workpiece held on the holding surface with a grinding wheel; an upper surface height measuring device that measures the upper surface height of the workpiece held on the holding surface; and a moving mechanism that relatively moves the chuck table and the upper surface height measuring device in a horizontal direction to position a measurement point measured by the upper surface height measuring device at a predetermined position. The measurement point of the upper surface height measuring device can pass near the center of the chuck table by the moving mechanism, and the dresser board held on the chuck table is a first dresser board in which a disk-shaped dressing grindstone having a first diameter is arranged at the center of the upper surface of the base covering the entire holding surface, or a second dresser board in which a disk-shaped dressing grindstone having a second diameter smaller than the first diameter is arranged at the center of the upper surface of the base. The determination unit is provided with a determination unit that at least determines whether it is the first dresser board or the second dresser board. The determination unit relatively moves the chuck table and the upper surface height measuring device by the moving mechanism, positions the measurement point by the upper surface height measuring device at a preset first position, measures the upper surface height of the dresser board held on the holding surface using the upper surface height measuring device, and determines whether the dresser board held on the holding surface is the first dresser board or the second dresser board based on whether the value measured by the upper surface height measuring device is the value of the height of the upper surface of the base or the value of the height of the upper surface of the dressing grindstone. The determination unit can determine a third dresser board in which a disk-shaped dressing grindstone having a third diameter smaller than the second diameter is arranged at the center of the upper surface of the base. When the value of the upper surface height of the dresser board held on the chuck table measured by the upper surface height measuring device with the measurement point positioned at the first position is the value of the height of the upper surface of the base, the determination unit moves the measurement point of the upper surface height measuring device to a second position that is closer to the center of the holding surface than the first position, measures the upper surface height of the dresser board held on the holding surface by the upper surface height measuring device at the second position, and determines whether the dresser board held on the holding surface is the second dresser board or the third dresser board based on whether the value measured by the upper surface height measuring device is the value of the height of the upper surface of the base or the value of the height of the upper surface of the dressing grindstone. Further, the determination unit can determine a fourth dresser board in which an annular disk-shaped dressing grindstone centered on the center of the upper surface of the base is arranged. The determination unit moves the measurement point by the upper surface height measuring device to the first position, A position closer to the center of the holding surface than the first position the second position, and a third position that is different from the first position and the second position. and outside the first position When the value measured by the upper surface height measuring device becomes the height of the dressing grindstone only at the first position or only at the third positionIt may be determined that the dresser board held by the holding surface is the fourth dresser board.

Advantages of the Invention

[0009] In the present invention, by measuring the height with the measurement point of the upper surface height measuring device as the first position, it is possible to determine whether the dresser board held by the holding surface is the first dresser board or the second dresser board. Therefore, it is possible to determine whether the held dresser board corresponds to the type of grinding wheel. Accordingly, it is possible to prevent dressing with a dressing grindstone that does not correspond to the type of grinding wheel. Further, when the measured value at the first position is not the height of the dressing grindstone, by moving the measurement point of the upper surface height measuring device to the second position, it is possible to determine whether the dresser board held on the chuck table is a third dresser board different from the first dresser board and the second dresser board. Furthermore, by moving the measurement point by the upper surface height measuring device to a third position different from the first position and the second position, and performing measurement by the upper surface height measuring device at each position, it is possible to determine whether it is a fourth dresser board having an annular plate-shaped dressing grindstone.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0011] The grinding device 1 shown in FIG. 1 is a device that grinds a workpiece held on a chuck table 2 using a grinding mechanism 3.

[0012] The chuck table 2 includes a suction portion 21 communicating with a suction source (not shown) and a frame body 22 that supports the suction portion 21. The upper surface of the suction portion 21 is a holding surface 210 for holding the workpiece, and is flush with the upper surface 220 of the frame body 22. The lower part of the frame body 22 is supported by a rotary support portion 23 and is driven by a motor provided in the rotary support portion 23 to be rotatable about a rotation axis 20. A cover 24 is disposed around the frame body 22, and bellows 25 are attached to both ends of the cover 24 in the Y-axis direction.

[0013] The chuck table 2 is driven by a moving mechanism 4 to be movable in the Y-axis direction. The moving mechanism 4 includes a ball screw 41 having a rotation axis 40 in the Y-axis direction, a pair of guide rails 42 disposed in parallel with the ball screw 41, a motor 43 that rotates the ball screw 41 about the rotation axis 40, an encoder 44 that detects the rotation angle of the motor 43, and a slide base 45 whose internal nut is screwed onto the ball screw 41 and whose bottom is in sliding contact with the guide rail 42. The rotary support portion 23 is fixed to the slide base 45. When the motor 43 rotates the ball screw 41, the slide base 45 is guided by the guide rail 42 and slides in the Y-axis direction, and thereby the chuck table 2 also moves in the Y-axis direction. The position of the chuck table 2 in the Y-axis direction is recognized by the encoder 44.

[0014] The grinding mechanism 3 includes a spindle 31 having a rotation axis 30 in the Z-axis direction, a housing 32 that rotatably supports the spindle 31, a motor 33 that rotates the spindle 31 about the rotation axis 30, a mount 34 connected to the lower end of the spindle 31, and a grinding wheel 35 attached to the mount 34. The grinding wheel 35 includes a wheel base 350 attached to the mount and a plurality of grinding wheels 351 annularly fixed to the lower surface of the wheel base 350.

[0015] The grinding mechanism 3 is supported by a grinding feed mechanism 5 so as to be movable up and down. The grinding feed mechanism 5 includes a ball screw 51 having a rotation axis 50 in the Z-axis direction, a pair of guide rails 52 disposed in parallel with the ball screw 51, a motor 53 that rotates the ball screw 51, a lifting base 54 whose internal nut is screwed onto the ball screw 51 and whose side portion is in sliding contact with the guide rail 52, and a holder 55 fixed to the lifting base 54 and supporting the housing 32 of the grinding mechanism 3. When the motor 53 rotates the ball screw 51, the lifting base 54 is guided by the guide rail 52 and moves up and down in the Z-axis direction, and thereby the grinding mechanism 3 also moves up and down in the Z-axis direction.

[0016] On the side of the movement path of the chuck table 2 in the Y-axis direction, a thickness measurement unit 6 for measuring the thickness of a workpiece or the like held by the chuck table 2 is disposed. The thickness measurement unit 6 includes two gauges. One is an upper surface height measuring instrument 61 that measures the height of the workpiece held by the chuck table 2, and the other is a holding surface height measuring instrument 62 that measures the height of the upper surface 220 of the frame body 22, that is, the height of the holding surface 210 of the chuck table 2. The thickness measurement unit 6 recognizes the difference between the measurement value of the upper surface height measuring instrument 61 and the measurement value of the holding surface height measuring instrument 62 as the thickness of the workpiece.

[0017] When grinding the workpiece, as shown in Fig. 2, the workpiece 8 is sucked and held on the holding surface 210 of the chuck table 2. The moving mechanism 4 moves the chuck table 2 at the loading / unloading position 201 in the +Y direction, and positions the chuck table 2 such that the rotating grinding wheel 351 passes through the center of the holding surface 210. The position of the chuck table 2 in the Y-axis direction at this time is referred to as the grinding position 202.

[0018] In this state, while the grinding wheel 35 rotates, the grinding feed mechanism 5 lowers the grinding mechanism 3, and the rotating grinding wheel 351 is brought into contact with the workpiece 8 for grinding. During grinding, the upper surface height measuring device 61 is brought into contact with the upper surface of the workpiece 8 to measure the height of the upper surface of the workpiece 8, and the holding surface height measuring device 62 is brought into contact with the upper surface of the frame body 22 to measure the height of the holding surface 210. The thickness measuring unit 6 calculates the difference between the height of the upper surface of the workpiece 8 and the height of the holding surface 210. When the calculated value reaches a predetermined value, the grinding feed mechanism 5 raises the grinding mechanism 3 to end the grinding.

[0019] In the process of grinding a plurality of workpieces in this way, dressing of the grinding wheel 351 is performed for the purpose of flattening the lower surface of the grinding wheel 351 or removing grinding chips adhering to the lower surface. Dressing of the grinding wheel 351 is performed by holding a dresser board having a dressing stone on the holding surface 210 of the chuck table 2 and bringing the lower surface of the rotating grinding wheel 351 into contact with this dressing stone. There are various dressing stones for the dresser board corresponding to the type of the grinding wheel 351. In order to prevent dressing from being performed using a dresser board not corresponding to the type of the grinding wheel 351, the grinding apparatus 1 is provided with a determination unit 7 for determining the type of the dresser board, as shown in Fig. 1.

[0020] Fig. 3 shows four types of dresser boards 11, 12, 13, and 14. All of these dresser boards 11, 12, 13, and 14 are provided with a base 15 having the same diameter and the same thickness. At the center of the upper surface 151 of the base 15 of the first dresser board 11, a disc-shaped first dressing grindstone 16 having a first diameter is fixed. At the center of the upper surface 151 of the base 15 of the second dresser board 12, a disc-shaped second dressing grindstone 17 having a second diameter smaller than the first diameter is fixed. At the center of the upper surface 151 of the base 15 of the third dresser board 13, a disc-shaped third dressing grindstone 18 having a third diameter smaller than the second diameter is fixed. At the center of the upper surface 151 of the base 15 of the fourth dresser board 14, a ring-shaped fourth dressing grindstone 19 having a fourth inner diameter and a fifth outer diameter is fixed. The first dressing grindstone 16, the second dressing grindstone 17, the third dressing grindstone 18, and the fourth dressing grindstone 19 have the same thickness. Note that the types of dresser boards are not limited to these, but hereinafter, the case of discriminating the types of dresser boards for these will be described.

[0021] When discriminating the types of dresser boards, using the moving mechanism 4 shown in FIG. 1, the chuck table 2 holding the dresser board on the holding surface 210 is moved in the Y-axis direction, and the chuck table 2 is positioned at a position where the upper surface height measuring instrument 61 can contact the dressing grindstone provided on the dresser board. Note that the base 15 of each dresser board covers the entire holding surface 210.

[0022] Specifically, for example, first, as shown in FIG. 3, the moving mechanism 4 is used to move the chuck table 2 in the Y-axis direction so that the measurement point of the upper surface height measuring instrument 61 is located at the first position 611. Here, the measurement point of the upper surface height measuring instrument 61 can pass near or through the center of the chuck table 2 by the moving mechanism 4, and the first position 611 means that the upper surface height measuring instrument 61 can contact the first dressing grindstone 16 having the largest diameter among the circular first dressing grindstone 16 of the first dresser board 11, the circular second dressing grindstone 17 of the second dresser board 12, and the circular third dressing grindstone 18 of the third dresser board 13, and is a position where it does not contact the second dressing grindstone 17, the third dressing grindstone 18, and the fourth dressing grindstone 19.

[0023] Next, lower the upper surface height measuring device 61 and measure the height when the movement stops. When the measured value of the upper surface height measuring device 61 is the height of the upper surface 161 of the first dressing grindstone 16, it is determined that the first dresser board 11 is held. When the measured value is the height of the base 15, it is determined that something other than the first dresser board 11 is held. Note that the diameters and heights of the dressing grindstones 16, 17, 18, and 19 have been recognized in advance by the determination unit 7.

[0024] When the measured value of the upper surface height measuring device 61 at the first position is not the height of the upper surface 161 of the first dressing grindstone 16 but the height of the upper surface 151 of the base 15, move the chuck table 2 in the -Y direction and position the measurement point of the upper surface height measuring device 61 at the second position 612 as shown in FIG. 4. Here, the second position 612 is a position closer to the center of the holding surface 210 than the first position 611, and the upper surface height measuring device 61 can contact the first dressing grindstone 16 having the largest circular diameter among the circular first dressing grindstone 16 of the first dresser board, the circular second dressing grindstone 17 of the second dresser board, and the circular third dressing grindstone 18 of the third dresser board, and the second largest diameter second dressing grindstone 17, and is a position where it does not contact the smallest diameter third dressing grindstone 18. When the measured value of the upper surface height measuring device 61 is the height of the upper surface 151 of the base 15 at the first position 611 and the height of the upper surface 171 of the second dressing grindstone 17 at the second position 612, the determination unit 7 determines that the second dresser board 12 having the second dressing grindstone 17 is held by the chuck table 2.

[0025] When the measured value of the upper surface height measuring device 61 is the height of the upper surface 151 of the base 15 at both the first position 611 and the second position 612, the chuck table 2 is moved in the +Y direction, and as shown in FIG. 5, the upper surface height measuring device 61 is moved to the third position 613. Here, the third position 613 is a position where the upper surface height measuring device 61 does not contact any of the circular first dressing grindstone 16 of the first dressing board 11, the circular second dressing grindstone 17 of the second dressing board 12, and the circular third dressing grindstone 18 of the third dressing board 13, and is a position where it can contact only the ring-shaped fourth dressing grindstone 19. When the measured value of the upper surface height measuring device 61 is the height of the upper surface 151 of the base 15 at the first position 611 and the second position 612, and is the height of the upper surface 191 of the dressing grindstone 19 at the third position 613, the determination unit 7 determines that the fourth dressing board 14 having the fourth dressing grindstone 19 is held by the chuck table 2.

[0026] When the measured value of the upper surface height measuring device 61 is the height of the upper surface 151 of the base 15 at the first position 611, the second position 612, and the third position 613, it is determined that the third dressing board 13 is held by the chuck table 2.

[0027] Note that the outer diameter of the fourth dressing grindstone 19 of the fourth dressing board 14 may be equal to the outer diameter of the first dressing grindstone 16 of the first dressing board 11. In that case, as shown in FIG. 6, the position where the upper surface height measuring device 61 can contact the fourth dressing grindstone 19 is defined as the first position 611, the inner side of the inner circumference of the fourth dressing grindstone 19 is defined as the second position 612, and the outer side of the outer circumference of the fourth dressing grindstone 19 is defined as the third position 613. When the measured value of the upper surface height measuring device 61 becomes the height of the upper surface 191 of the dressing grindstone 19 only at the first position 611, it may be determined that the fourth dressing board 14 is held by the chuck table 2.

[0028] In this way, the determination unit 7 determines which dresser board is held on the chuck table 2. When the dresser board corresponds to the grinding wheel 351, the chuck table 2 is moved to the grinding position 202 shown in Fig. 2, the grinding wheel 35 is rotated, and the grinding feed mechanism 5 lowers the grinding mechanism 3 to bring the rotating grinding wheel 351 into contact with the dressing stone for grinding. As a result, the lower surface of the grinding wheel 351 is dressed.

[0029] When dressing is performed in this way, the dressing stone wears out. Therefore, when the dressing stone falls below a predetermined thickness, it is necessary to replace the dressing board having the dressing stone. Therefore, the thickness of the dressing stone is measured using the thickness measurement unit 6 shown in Fig. 1. Hereinafter, the first dresser board 11 having the first dressing stone 16 and the second dresser board 12 having the second dressing stone 17 will be described as examples.

[0030] First, as shown in Fig. 7, the chuck table 2 is moved to the first remaining amount measurement position 203 using the moving mechanism 4 shown in Fig. 1. This first remaining amount measurement position 203 is a position where the upper surface height measuring device 61 can contact the first dressing stone 16 and the second dressing stone 17 and a position where the holding surface height measuring device 62 can contact the base 15 of the first dresser board 11 and the second dresser board 12. In this state, the upper surface height measuring device 61 is brought into contact with the upper surface 161 of the first dressing stone 16 or the upper surface 171 of the second dressing stone 17 to measure its height, and the holding surface height measuring device 62 is brought into contact with the upper surface 151 of the base 15 to measure its height. Then, by obtaining the difference between the height of the upper surface 161 of the first dressing stone 16 or the upper surface 171 of the second dressing stone 17 and the height of the upper surface 151 of the base 15 in the thickness measurement unit 6, the thickness of the first dressing stone 16 or the second dressing stone 17, that is, the remaining amount can be calculated. When the obtained thickness is less than the predetermined thickness, the dresser board is removed from the chuck table 2 and a new dresser board is held. Note that the upper surface height measuring device 61 and the holding surface height measuring device 62 are adjusted to measure the height of the holding surface 210 and show the same value, for example.

[0031] Note that, as shown in FIG. 8, the chuck table 2 may be positioned at the second remaining amount measurement position 204. This second remaining amount measurement position 204 is a position where the upper surface height measuring device 61 can contact the center of the first dressing grindstone 16 and the holding surface height measuring device 62 can contact the outer peripheral portion of the first dressing grindstone 16, and is also a position where the upper surface height measuring device 61 can contact the center of the second dressing grindstone 17 and the holding surface height measuring device can contact the base 15 of the second dresser board. In this state, the upper surface height measuring device 61 is brought into contact with the upper surfaces 161 of the first dressing grindstone 16 and the second dressing grindstone 17 to measure their heights, and the holding surface height measuring device 62 is brought into contact with the upper surfaces 161 of the first dressing grindstone 16 and the upper surface 151 of the base 15 to measure their heights. Then, when the measured value by the upper surface height measuring device 61 is the height of the upper surface 161 of the first dressing grindstone 16 and the measured value by the holding surface height measuring device 62 is also the height of the upper surface 161 of the first dressing grindstone 16, the determination unit 7 can determine that the first dresser board 11 is held on the chuck table 2. On the other hand, when the measured value by the upper surface height measuring device 61 is the height of the upper surface 171 of the second dressing grindstone 17 and the measured value by the holding surface height measuring device 62 is the height of the upper surface 151 of the substrate 15 of the second dressing grindstone 17, the thickness of the second dressing grindstone 17, that is, the remaining amount, can be calculated by obtaining the difference between the height of the upper surface 171 of the second dressing grindstone 17 and the height of the upper surface 151 of the base 15 in the thickness measuring unit 6. And when the obtained thickness is less than a predetermined thickness, the dresser board is removed from the chuck table 2 and a new dresser board is held. In this way, by using the holding surface height measuring device 62, not only can the remaining amount of the dressing grindstone be measured, but also the type of the dressing grindstone of the dresser board held on the chuck table 2 can be discriminated.

[0032] In the above-described embodiment, the moving mechanism 4 moves the chuck table 2 in the Y-axis direction to adjust the measurement position of the upper surface height measuring instrument 61. However, the upper surface height measuring instrument 61 may be configured to move in the Y-axis direction. Further, the moving mechanism is not limited to a configuration in which the chuck table 2 and the upper surface height measuring instrument 61 linearly move relative to each other. For example, the chuck table 2 may be supported by a turntable so as to be rotatable around a common axis. That is, the moving mechanism may be any mechanism that relatively moves the chuck table 2 and the upper surface height measuring instrument 61 in the horizontal direction.

[0033] As described above, by taking advantage of the fact that the diameter of the dressing grindstone varies depending on its type and performing measurement while moving the measurement point of the upper surface height measuring instrument, it is possible to discriminate the type of dressing grindstone, and it is possible to prevent dressing using a dressing grindstone that does not correspond to the type of grinding grindstone.

Explanation of Reference Numerals

[0034] 1: Grinding device 2: Chuck table 20: Rotating shaft 21: Suction part 210: Holding surface 22: Frame body 220: Upper surface 23: Rotary support part 24: Cover 25: Bellows 201: Loading / unloading position 202: Grinding position 203: First remaining amount measurement position 204: Second remaining amount measurement position 3: Grinding mechanism 30: Rotating shaft 31: Spindle 32: Housing 33: Motor 34: Mount 35: Grinding wheel 350: Wheel base 351: Grinding grindstone 4: Moving mechanism 40: Rotating shaft 41: Ball screw 42: Guide rail 43: Motor 44: Encoder 45: Slide base 5: Grinding feed mechanism 50: Rotating shaft 51: Ball screw 52: Guide rail 53: Motor 54: Lifting base 55: Holder 6: Thickness measurement unit 61: Upper surface height measuring device 611: First position 612: Second position 613: Third position 62: Holding surface height measuring device 7: Judgment unit 8: Workpiece 11: First dresser board 16: First dressing grindstone 161: Upper surface 12: Second dresser board 17: Second dressing grindstone 171: Upper surface 13: Third dresser board 18: Third dressing grindstone 181: Upper surface 14: Fourth dresser board 19: Fourth dressing grindstone 191: Upper surface 15: Base 151: Upper surface

Claims

1. A grinding apparatus comprising: a chuck table for holding a workpiece or a dresser board on a holding surface; a grinding mechanism for grinding the workpiece held on the holding surface with a grinding wheel; an upper surface height measuring device for measuring the upper surface height of the workpiece held on the holding surface; and a moving mechanism for relatively moving the chuck table and the upper surface height measuring device in a horizontal direction to position a measurement point measured by the upper surface height measuring device at a predetermined position, the measurement point of the upper surface height measuring device can pass near the center of the chuck table by the moving mechanism, and comprising a determination unit for at least determining whether the dresser board held on the chuck table is a first dresser board having a disk-shaped dressing grindstone with a first diameter disposed at the center of the upper surface of a base covering the entire holding surface, or a second dresser board having a disk-shaped dressing grindstone with a second diameter smaller than the first diameter disposed at the center of the upper surface of the base, the determination unit, relatively moves the chuck table and the upper surface height measuring device by the moving mechanism to position the measurement point by the upper surface height measuring device at a preset first position, measures the upper surface height of the dresser board held on the holding surface using the upper surface height measuring device, and determines whether the dresser board held on the holding surface is the first dresser board or the second dresser board according to whether the value measured by the upper surface height measuring device is the value of the height of the upper surface of the base or the value of the height of the upper surface of the dressing grindstone, a grinding apparatus.

2. the determination unit can discriminate a third dresser board having a disk-shaped dressing grindstone with a third diameter smaller than the second diameter disposed at the center of the upper surface of the base, the determination unit, when the value of the upper surface height of the dresser board held on the chuck table measured by the upper surface height measuring device with the measurement point positioned at the first position is the value of the height of the upper surface of the base, moves the measurement point of the upper surface height measuring device to a second position closer to the center of the holding surface than the first position, measures the upper surface height of the dresser board held on the holding surface by the upper surface height measuring device at the second position, and determines whether the dresser board held on the holding surface is the second dresser board or the third dresser board according to whether the value measured by the upper surface height measuring device is the value of the height of the upper surface of the base or the value of the height of the upper surface of the dressing grindstone, The grinding apparatus according to Claim 1.

3. The determination unit can discriminate a fourth dresser board on which an annular plate-shaped dressing grindstone centered on the center of the upper surface of the base is arranged. The determination unit moves the measurement point by the upper surface height measuring device to a first position, a second position that is closer to the center of the holding surface than the first position, and a third position that is different from the first position and the second position in the radial direction of the circle centered on the center of the base and is outside the first position. When the value measured by the upper surface height measuring device becomes the height of the dressing grindstone only at the first position or only at the third position, it is determined that the dresser board held by the holding surface is the fourth dresser board. The grinding device according to claim 1.

Images