JP2024010709A - dressing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dressing method that can perform perfect dressing for a plurality of grindstones.

SOLUTION: A dressing step for dressing a plurality of grindstones is performed while measuring a thickness of a dresser board, and the dressing step is terminated when a value, that is calculated by use of the thickness of the dresser board measured at the dressing step, becomes a prescribed value. By this, it is possible to perform perfect dressing for the plurality of grindstones.

SELECTED DRAWING: Figure 4

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a dressing method for dressing a plurality of grinding wheels provided on one side of an annular grinding wheel.

2. Description of the Related Art Device chips such as ICs (Integrated Circuits) are essential components in various electronic devices such as mobile phones and personal computers. Such chips are manufactured by, for example, thinning a workpiece, such as a wafer, on which a large number of devices are formed, and then dividing the workpiece into regions containing individual devices.

Examples of methods for thinning the workpiece include grinding the back side of the workpiece using a grinding device. This grinding device generally includes a chuck table that holds the front (bottom) side of the workpiece on a holding surface, and a plurality of grinding wheels that extend along the vertical direction and are provided on the bottom side. and a spindle attached to the lower end of the annular grinding wheel.

Each of the plurality of grinding wheels is made of, for example, a bond material such as vitrified bond or resin bond containing pores, and abrasive grains such as diamond or cubic boron nitride (cBN) dispersed in the bond material. and has. In the grinding device, the workpiece is thinned, for example, in the following order.

First, the front (lower) side of the workpiece is held on the holding surface of the chuck table. Both the chuck table and spindle are then rotated with the grinding wheel positioned above the chuck table. Next, the chuck table and the spindle are relatively moved along the vertical direction so that the grinding surfaces (lower surfaces) of the plurality of grinding wheels are brought into contact with the back surface (upper surface) of the workpiece.

As a result, the back surface (upper surface) side of the workpiece is ground by the abrasive grains exposed on the grinding surfaces (lower surface) of the plurality of grinding wheels. Furthermore, by continuing to move the chuck table and spindle relative to each other along the vertical direction, a portion having a predetermined thickness on the back (top) side of the workpiece is removed, and the workpiece is thinned. Ru.

However, if grinding debris generated by grinding the workpiece adheres to the grinding surface of the grinding wheel, the abrasive grains may not be sufficiently exposed (clogged) on the grinding surface of the grinding wheel. Further, as the workpiece is repeatedly ground, the abrasive grains exposed on the grinding surface of the grinding wheel may become worn out (clogged). Furthermore, when the grinding wheel attached to the lower end of the spindle is replaced, the positions (heights) of the grinding surfaces of the plurality of grinding wheels may shift.

In these cases, the efficiency of grinding the workpiece in the grinding device may be reduced. Therefore, in grinding devices, a process (dressing) is often performed at appropriate timing to prepare the grinding surfaces (lower surfaces) of a plurality of grinding wheels to make them suitable for grinding (for example, see Patent Document 1). ). In the grinding device, dressing of a plurality of grinding wheels is performed in the following order, for example.

First, a dresser board with abrasive grains exposed on its upper surface is held on a holding surface of a chuck table. Both the chuck table and spindle are then rotated with the grinding wheel positioned above the dresser board. Next, the chuck table and the spindle are moved relative to each other in the vertical direction so that the grinding surfaces of the plurality of grinding wheels come into contact with the upper surface of the dresser board.

As a result, the plurality of grinding wheels and the dresser board are ground together. That is, the upper surface side of the dresser board is ground by the abrasive grains exposed on the grinding surfaces of the plurality of grinding wheels, and the grinding surface side of the plurality of grinding wheels is ground by the abrasive grains exposed at the upper surface of the dresser board.

Japanese Patent Application Publication No. 9-29630

If dressing of the plurality of grinding wheels is insufficient, it becomes difficult to sufficiently recover the reduced efficiency of grinding the workpiece. Therefore, when dressing a plurality of grinding wheels, excessive dressing is often performed. However, this increases the time required for dressing and may shorten the life of the grinding wheel and dresser board.

In view of this point, an object of the present invention is to provide a dressing method that can dress a plurality of grinding wheels without excess or deficiency.

According to the present invention, there is provided a dressing method for dressing a plurality of grinding wheels provided on one side of an annular grinding wheel, which comprises: a holding step of holding a dresser board on a holding surface of a chuck table; While rotating the grinding wheel along the circumferential direction and rotating the chuck table along the circumferential direction of the chuck table, the grinding wheel and the dresser board are in contact with each other. a dressing step of dressing the plurality of grinding wheels by bringing them closer together with a chuck table; the dressing step is performed while measuring the thickness of the dresser board; and the dressing step is performed while measuring the thickness of the dresser board; A dressing method is provided that ends when a value calculated using the method reaches a predetermined value.

Further, the calculated value is a thickness reduction of the dresser board calculated by subtracting the thickness of the dresser board measured in the dressing step from the thickness of the dresser board at the beginning of the dressing step. It is preferable.

Alternatively, the calculated value is calculated by subtracting the thickness reduction of the dresser board from the distance at which the grinding wheel and the chuck table approach during dressing of the plurality of grinding wheels. Preferably, the thickness reduction of the dresser board is calculated by subtracting the thickness of the dresser board measured in the dressing step from the thickness of the dresser board at the start of the dressing step. .

In the present invention, the dressing step of dressing a plurality of grinding wheels is carried out while measuring the thickness of the dresser board, and the value calculated using the thickness of the dresser board measured in this dressing step is a predetermined value. The dressing step ends when the value is reached. Thereby, it becomes possible to dress a plurality of grinding wheels without excess or deficiency.

FIG. 1 is a perspective view schematically showing an example of a grinding device. FIG. 2 is a cross-sectional view schematically showing an example of a grinding device. FIG. 3 is a functional block diagram schematically showing an example of a control unit built into the grinding device. FIG. 4 is a flowchart schematically showing an example of a dressing method for dressing a plurality of grinding wheels in a grinding device.

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing an example of a grinding device, and FIG. 2 is a sectional view schematically showing an example of the grinding device shown in FIG. Note that the X-axis direction (front-back direction) and Y-axis direction (left-right direction) shown in FIGS. 1 and 2 are directions perpendicular to each other on the horizontal plane, and the Z-axis direction (vertical direction) is the same as the X-axis direction. This is a direction (vertical direction) perpendicular to the Y-axis direction and the Y-axis direction.

The grinding device 2 shown in FIGS. 1 and 2 has a base 4 that supports each component. A rectangular parallelepiped groove 4a extending along the X-axis direction is formed on the upper surface of the base 4. As shown in FIG. An X-axis direction movement mechanism 6 for moving a chuck table 24, which will be described later, along the X-axis direction is provided on the bottom surface of the groove 4a.

This X-axis direction movement mechanism 6 has a pair of guide rails 8 each extending along the X-axis direction. A rectangular parallelepiped-shaped X-axis moving plate 10 is attached to the upper side of the pair of guide rails 8 so as to be slidable along the X-axis direction. Furthermore, a screw shaft 12 extending along the X-axis direction is arranged between the pair of guide rails 8 .

A pulse motor 14 for rotating the screw shaft 12 is connected to the rear end of the screw shaft 12. Further, a nut 16 is provided on the outer circumferential surface of the screw shaft 12 on which a thread is formed, and the nut 16 accommodates a large number of balls that circulate according to the rotation of the screw shaft 12, thereby forming a ball screw.

Further, the nut 16 is fixed to the lower surface side of the X-axis moving plate 10. Therefore, when the screw shaft 12 is rotated by the pulse motor 14, the X-axis moving plate 10 moves along the X-axis direction together with the nut 16. Further, on the X-axis moving plate 10, there is a rotating body to which a driven pulley 18 is connected at the lower end, and a rotational drive source (not shown) such as a motor connected to a driving pulley (not shown). It is provided.

Further, an endless belt (not shown) is stretched between the driven pulley 18 and the driving pulley. Further, on the X-axis moving plate 10, there is provided a tilt adjustment mechanism having one fixed axis (not shown) and two movable axes 20 whose lengths along the Z-axis direction are variable. There is. Further, the fixed shaft and the two movable shafts 20 are connected to the lower surface side of the table base 22 and support the table base 22.

A through hole (not shown) is formed in the center of the table base 22, and a rotating body to which the driven pulley 18 is connected at its lower end passes through the through hole. The upper end of this rotating body is connected to the lower surface of a disc-shaped chuck table 24. Therefore, when the rotational drive source connected to the driving pulley is operated to rotate the endless belt placed on the driven pulley 18, the chuck table 24 rotates along the circumferential direction of the chuck table 24.

Furthermore, the chuck table 24 is supported by the table base 22 via a bearing (not shown). Therefore, even if the chuck table 24 is rotated as described above, the table base 22 will not rotate. On the other hand, when the length of each of the two movable shafts 20 along the Z-axis direction is adjusted in the inclination adjustment mechanism, not only the inclination of the table base 22 but also the chuck table 24 is adjusted.

The chuck table 24 has a disc-shaped frame 26 made of ceramics or the like. This frame body 26 has a disk-shaped bottom wall and a cylindrical side wall that stands up from the bottom wall. That is, a disc-shaped recess defined by a bottom wall and side walls is formed on the upper surface side of the frame 26. Further, a flow path (not shown) that opens at the bottom of the recess is formed in the bottom wall of the frame 26, and this flow path communicates with a suction source (not shown) such as an ejector.

Furthermore, a disc-shaped porous plate 28 having a diameter approximately equal to the diameter of this recess is fixed to the recess formed on the upper surface side of the frame 26. This porous plate 28 is made of porous ceramics, for example. Further, the upper surface of the porous plate 28 and the upper surface of the side wall of the frame body 26 have a shape corresponding to the side surface of a cone (a shape in which the center protrudes beyond the outer periphery).

Then, when a suction source communicating with the flow path formed inside the frame body 26 is operated, a suction force acts on the space near the upper surface of the porous plate 28 . Therefore, the upper surface of the porous plate 28 and the upper surface of the side wall of the frame body 26 function as a holding surface 24a of the chuck table 24 (see FIG. 1).

For example, by operating the suction source with the disk-shaped workpiece 11 or the dresser board 21 placed on the holding surface 24a of the chuck table 24, the workpiece 11 or the dresser board 21 can be held on the chuck table 24. It is held at surface 24a. Note that the diameters of each of the workpiece 11 and the dresser board 21 are larger than the inner diameter of the side wall of the frame 26 and smaller than the outer diameter thereof.

The workpiece 11 is made of, for example, a semiconductor material such as silicon, and has a wafer 13 on which a plurality of devices are formed on its surface 13a. Furthermore, a protective tape 15 made of resin, for example, is attached to the front surface 13a of the wafer 13 to prevent damage to the device when the back surface 13b of the wafer 13 is ground.

The dresser board 21 has a disk-shaped support portion 23 made of resin such as polyvinyl chloride, for example. Furthermore, a disc-shaped dressing part 25 having a smaller diameter than the support part 23 is attached to the center of the upper surface of the support part 23 via an adhesive. The dressing portion 25 is formed, for example, by kneading abrasive grains made of silicon carbide (SiC), aluminum oxide (Al ₂ O ₃ ), etc. into a bond material such as vitrified bond or resin bond, and then firing the mixture. Ru.

The workpiece 11 is held on the chuck table 24 so that the wafer 13 is held via the protective tape 15, that is, the back surface 13b of the wafer 13 is exposed. Further, the dresser board 21 is held on the chuck table 24 so that the dressing part 25 is held via the support part 23, that is, the dressing part 25 is exposed.

Further, a rectangular parallelepiped table cover 30 is provided around the chuck table 24 so that the holding surface 24a thereof is exposed. The width of this table cover 30 (length along the Y-axis direction) is approximately equal to the width of the groove 4a formed on the upper surface of the base 4. In addition, dust-proof and drip-proof covers 32 that are extendable and retractable along the X-axis direction are provided before and after the table cover 30.

Further, a quadrangular columnar support structure 34 is provided in a region of the upper surface of the base 4 located behind the groove 4a. A Z-axis direction movement mechanism 36 is provided on the front surface of the support structure 34. This Z-axis direction movement mechanism 36 has a pair of guide rails 38 each extending along the Z-axis direction. A slider 40 is provided on the front side of each of the pair of guide rails 38 so as to be slidable along the Z-axis direction (see FIG. 2).

Further, the front end portion of the slider 40 is fixed to the rear side of a rectangular parallelepiped-shaped Z-axis moving plate 42. Further, a screw shaft 44 extending along the Z-axis direction is arranged between the pair of guide rails 38. A pulse motor 46 for rotating the screw shaft 44 is connected to the upper end of the screw shaft 44 .

Further, a nut 48 is provided on the outer circumferential surface of the screw shaft 44 on which a thread is formed, and accommodates a large number of balls that circulate according to the rotation of the screw shaft 44, thereby forming a ball screw. Further, the nut 48 is fixed to the rear surface side of the Z-axis moving plate 42. Therefore, when the screw shaft 44 is rotated by the pulse motor 46, the Z-axis moving plate 42 moves along the Z-axis direction together with the nut 48.

A grinding unit 50 is provided on the front side of the Z-axis moving plate 42. This grinding unit 50 has a cylindrical holding member 52 fixed to the front surface of the Z-axis moving plate 42. A cylindrical spindle housing 54 extending along the Z-axis direction is provided inside the holding member 52.

Furthermore, a cylindrical spindle 56 extending along the Z-axis direction is provided inside the spindle housing 54 (see FIG. 2). The spindle 56 is rotatably supported by the spindle housing 54, and its upper end is connected to a rotational drive source 58 such as a motor.

Further, a lower end portion of the spindle 56 is exposed from the spindle housing 54 and is fixed to a disc-shaped wheel mount 60. An annular grinding wheel 62 having an outer diameter approximately equal to the diameter of the wheel mount 60 is attached to the lower surface of the wheel mount 60 using a fixing member (not shown) such as a bolt.

A plurality of grinding wheels 62a are provided on one surface (lower surface) of the grinding wheel 62. The plurality of grinding wheels 62a are fixed to the lower surface of the wheel base 62b in a discrete manner in an annular manner. When the rotational drive source 58 is operated, the grinding wheel 62 rotates along the circumferential direction of the grinding wheel 62.

Note that the plurality of grinding wheels 62a have abrasive grains such as diamond or cBN dispersed in a bond material such as vitrified bond or resin bond. Further, the wheel base 62b is made of a metal material such as stainless steel or aluminum, for example.

Furthermore, a grinding water supply nozzle is provided near the grinding wheel 62. This grinding water supply nozzle supplies a liquid (grinding water) such as pure water to a processing point at a predetermined flow rate when grinding the workpiece 11 with the plurality of grinding wheels 62a.

Further, a measurement unit 64 is provided in a region of the upper surface of the base 4 located on the side of the groove 4 a and close to the grinding unit 50 . This measurement unit 64 includes, for example, a pair of height gauges 64a and 64b that measure the height of the position where each probe touches.

The measuring tip of the height gauge 64a can be arranged so as to be in contact with the upper surface of the porous plate 28 of the chuck table 24. Further, when the workpiece 11 or the dresser board 21 is held on the holding surface 24a of the chuck table 24, the measuring head of the height gauge 64a is attached to the upper surface of these (specifically, the wafer included in the workpiece 11). 13 or the upper surface of the dressing part 25 included in the dresser board 21).

Further, the measuring tip of the height gauge 64b can be arranged so as to be in contact with the upper surface of the side wall of the frame 26 of the chuck table 24. The measuring point of the height gauge 64a is arranged so as to be in contact with the upper surface of the workpiece 11 or the dresser board 21, and the measuring point of the height gauge 64b is arranged so as to be in contact with the upper surface of the side wall of the frame 26 of the chuck table 24. If so, the thickness of the workpiece 11 or the dresser board 21 can be measured in the measurement unit 64.

Furthermore, the grinding device 2 includes a control unit that controls the above-mentioned components. FIG. 3 is a functional block diagram schematically showing an example of a control unit built into the grinding device 2. As shown in FIG. The control unit 66 shown in FIG. 3 includes a processing section 68 and a storage section 70.

The processing unit 68 is configured by a processor such as a CPU (Central Processing Unit). The storage unit 70 also includes volatile memory such as DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory), SSD (Solid State Drive) (NAND flash memory), or HDD (Hard). Disk Drive) (magnetic memory) device) and other non-volatile memory.

The storage unit 70 stores various types of information (specifically, data, programs, etc.) used in the processing unit 68. For example, the storage unit 70 stores the value (predetermined value) of the thickness reduction of the dresser board 21 or the plurality of grinding wheels 62a necessary for dressing the plurality of grinding wheels 62a with just the right amount. There is.

Further, the processing unit 68 reads and executes various programs stored in the storage unit 70 to control the components of the grinding device 2 . This processing section 68 includes, for example, a driving section 72 and a calculating section 74.

The drive unit 72 controls the movement or rotation of the components of the grinding device 2 . That is, the drive unit 72 includes the X-axis direction movement mechanism 6 (specifically, the pulse motor 14), the Z-axis direction movement mechanism 36 (specifically, the pulse motor 46), and the tilt adjustment mechanism (specifically, the pulse motor 46). controls the movable shaft 20 ), the rotational drive source that rotates the chuck table 24 , and the rotational drive source 58 that rotates the grinding wheel 62 .

The calculation unit 74 uses the thickness of the dresser board 21 measured by the measuring unit 64 to determine whether or not to finish dressing the plurality of grinding wheels 62a (for example, the thickness of the dresser board 21 or the plurality of (thickness reduction of the grinding wheel 62a) is calculated. Note that a specific method for calculating this value will be described later.

FIG. 4 is a flowchart schematically showing an example of a dressing method for dressing a plurality of grinding wheels 62a in the grinding device 2. As shown in FIG. In this method, first, the dresser board 21 is held on the holding surface 24a of the chuck table 24 (holding step: S1).

Specifically, the dresser board 21 is carried into the chuck table 24 so that the center of the lower surface of the support portion 23 of the dresser board 21 coincides with the center of the holding surface 24a of the chuck table 24. Then, a suction force is applied to the support portion 23 of the dresser board 21 by operating a suction source that communicates with the flow path formed in the bottom wall of the frame 26 of the chuck table 24 .

Thereby, the support portion 23 is elastically deformed so as to follow the holding surface 24a of the chuck table 24. That is, the lower surface of the support part 23 has a shape corresponding to the side surface of the cone, and the holding surface 24a of the chuck table 24 is covered by the support part 23. As a result, the dresser board 21 is held on the holding surface 24a of the chuck table 24.

Next, the plurality of grinding wheels 62a are dressed while measuring the thickness of the dresser board 21 (dressing step: S2). Specifically, first, the position of the chuck table 24 in the X-axis direction is adjusted so that the trajectory when the plurality of grinding wheels 62a are rotated and the dressing portion 25 of the dresser board 21 overlap in the Z-axis direction.

In addition, in this adjustment, for example, a line segment connecting the center and outer circumference of the holding surface 24a of the chuck table 24 at the shortest distance and orthogonal to the Z-axis direction, a trajectory of the plurality of rotating grinding wheels 62a, are overlapped in the Z-axis direction.

That is, the coordinates of the line segment in the coordinate plane (XY coordinate plane) perpendicular to the Z-axis direction and the coordinates of the trajectory are overlapped. Therefore, if necessary, the inclination of the chuck table 24 may be adjusted by operating the inclination adjustment mechanism prior to this adjustment.

Next, the measuring point of the height gauge 64a is arranged so as to be in contact with the upper surface of the dressing part 25, and the measuring point of the height gauge 64b is arranged so as to be in contact with the upper surface of the side wall of the frame 26 of the chuck table 24.

At this time, the measuring unit 64 measures the thickness of the dresser board 21 at the start of the dressing step (S2). This thickness value is then stored in the storage section 70 of the control unit 66. Furthermore, the measurement of the thickness of the dresser board 21 by the measurement unit 64 is continuously performed during the dressing step (S2).

Next, while rotating both the grinding wheel 62 and the chuck table 24, the grinding wheel 62 and the chuck table 24 are brought close to each other so that the lower surfaces of the plurality of grinding wheels 62a and the upper surface of the dressing section 25 are brought into contact with each other. Lower the wheel 62.

Note that when the lower surfaces of the plurality of grinding wheels 62a and the upper surface of the dressing section 25 come into contact, the current supplied to the rotation drive source 58 for rotating the grinding wheel 62 increases, and the load applied to the grinding unit 50 also increases. growing.

Therefore, by detecting this current or load, it is possible to grasp the timing at which the lower surfaces of the plurality of grinding wheels 62a and the upper surface of the dressing section 25 come into contact. In the grinding device 2, the position (height) of the nut 48 at this timing may be stored in the storage section 70 of the control unit 66.

Further, while rotating both the grinding wheel 62 and the chuck table 24, the grinding wheel 62 and the chuck table 24 are brought close to each other while the plurality of grinding wheels 62a are in contact with the dressing portion 25 of the dresser board 21, that is, The grinding wheel 62 is lowered.

As a result, the plurality of grinding wheels 62a and the dressing portion 25 of the dresser board 21 are ground together, and the plurality of grinding wheels 62a are dressed. Furthermore, if the value calculated using the thickness of the dresser board 21 is not the predetermined value stored in the storage unit 70 (step (S3): NO), dressing of the plurality of grinding wheels 62a is continued. In other words, the grinding wheel 62 is further lowered.

Here, the value calculated using the thickness of the dresser board 21 is, for example, a reduction in the thickness of the dresser board 21. Specifically, the thickness reduction of the dresser board 21 is determined by the thickness of the dresser board 21 measured during the dressing step (S2) from the thickness of the dresser board 21 at the start of the dressing step (S2) stored in the storage unit 70. It can be calculated by subtracting the thickness of

Alternatively, the value calculated using the thickness of the dresser board 21 may be a reduction in the thickness of the plurality of grinding wheels 62a. Specifically, the thickness reduction of the plurality of grinding wheels 62a is achieved by subtracting the thickness reduction of the dresser board 21 from the distance at which the grinding wheel 62 and the chuck table 24 approach each other during dressing of the plurality of grinding wheels 62a. It can be calculated.

Note that the distance at which the grinding wheel 62 and the chuck table 24 approach each other during dressing of the plurality of grinding wheels 62a is stored in the storage section 70, and is the distance at which the lower surface of the plurality of grinding wheels 62a and the upper surface of the dressing section 25 come into contact. It can be calculated by subtracting the height of the nut 48 during the dressing step (S2) from the height of the nut 48 at the timing.

Then, if the value calculated using the thickness of the dresser board 21 reaches the predetermined value stored in the storage unit 70 (step (S3): YES), dressing of the plurality of grinding wheels 62a is finished. That is, in this case, the rotation of both the grinding wheel 62 and the chuck table 24 is stopped, and the grinding wheel 62 is raised so as to separate the plurality of grinding wheels 62a from the dresser board 21.

In the dressing method shown in FIG. 4, a dressing step (S2) of dressing a plurality of grinding wheels 62a is carried out while measuring the thickness of the dresser board 21, and the dresser board measured in this dressing step (S2) is The dressing step (S2) ends when the value calculated using the thickness of 21 reaches a predetermined value. Thereby, it becomes possible to dress the plurality of grinding wheels 62a without excess or deficiency.

Note that the content described above is one embodiment of the present invention, and the present invention is not limited to the content described above. For example, the structure of the grinding device used in the present invention is not limited to the structure of the grinding device 2 described above. Specifically, the grinding apparatus of the present invention includes a Z-axis movement mechanism for moving the chuck table 24 along the Z-axis direction, and an X-axis movement mechanism for moving the grinding unit 50 along the X-axis direction. A directional movement mechanism may also be provided.

In addition, the structure, method, etc. according to the embodiments described above can be modified and implemented as appropriate without departing from the scope of the objective of the present invention.

2: Grinding device 4: Base (4a: groove)
6: X-axis direction movement mechanism 8: Guide rail 10: X-axis movement plate 11: Workpiece 12: Screw shaft 13: Wafer (13a: front surface, 13b: back surface)
14: Pulse motor 15: Protective tape 16: Nut 18: Driven pulley 20: Movable axis 21: Dresser board 22: Table base 23: Support part 24: Chuck table (24a: holding surface)
25: Dressing part 26: Frame body 28: Porous plate 30: Table cover 32: Dust-proof and drip-proof cover 34: Support structure 36: Z-axis direction movement mechanism 38: Guide rail 40: Slider 42: Z-axis movement plate 44: Screw shaft 46: Pulse motor 48: Nut 50: Grinding unit 52: Holding member 54: Spindle housing 56: Spindle 58: Rotation drive source 60: Wheel mount 62: Grinding wheel (62a: Grinding wheel, 62b: Wheel base)
64: Measurement unit (64a, 64b: height gauge)
66: Control unit 68: Processing section 70: Storage section 72: Drive section 74: Calculation section

Claims (3)

A dressing method for dressing a plurality of grinding wheels provided on one side of an annular grinding wheel, the method comprising:
a holding step for holding the dresser board on the holding surface of the chuck table;
While rotating the grinding wheel along the circumferential direction of the grinding wheel and rotating the chuck table along the circumferential direction of the chuck table, the plurality of grinding wheels and the dresser board are in contact with each other. a dressing step of dressing the plurality of grinding wheels by bringing the grinding wheel and the chuck table closer together,
The dressing method is such that the dressing step is performed while measuring the thickness of the dresser board, and ends when a value calculated using the measured thickness of the dresser board reaches a predetermined value. 2. The calculated value is a thickness reduction of the dresser board calculated by subtracting the thickness of the dresser board measured in the dressing step from the thickness of the dresser board at the beginning of the dressing step. The dressing method described in 1. The calculated value is the thickness of the plurality of grinding wheels calculated by subtracting the thickness reduction of the dresser board from the distance at which the grinding wheel and the chuck table approach during dressing of the plurality of grinding wheels. weight loss,
2. The dressing method of claim 1, wherein the thickness reduction of the dresser board is calculated by subtracting the thickness of the dresser board measured in the dressing step from the thickness of the dresser board at the beginning of the dressing step.

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