JP2024086023A - Grinding wheel and grinding method - Google Patents

Abstract

A grinding wheel capable of being dressed without reducing productivity is provided.
[Solution] A grinding wheel for grinding a workpiece, comprising a circular wheel base and a plurality of grinding wheels arranged in a ring shape on one surface of the wheel base, wherein the grinding wheels have a base portion having a mounting surface for mounting to the wheel base, and a wear-promoting portion having a grinding surface that contacts the workpiece and is more susceptible to wear than the base portion.
[Selected figure] Figure 3

Description

The present invention relates to a grinding wheel and a grinding method used to grind a workpiece.

A plate-shaped workpiece, such as a semiconductor wafer on which devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integration) are formed, is divided along planned division lines (streets) to obtain multiple device chips, each of which contains a device. These device chips are built into various electronic devices, such as personal computers and mobile phones. In recent years, as electronic devices have become smaller and thinner, there has been a demand for device chips to be smaller and thinner as well. Therefore, a method is used in which the workpiece is thinned by grinding it with a grinding wheel.

To grind the workpiece, a grinding device is used that includes a chuck table that holds the workpiece and a grinding unit that grinds the workpiece held by the chuck table. The grinding unit of the grinding device includes a wheel mount that is fixed to the tip of a spindle that serves as a rotation axis, and a grinding wheel equipped with a grinding stone for grinding the workpiece is attached to the wheel mount (see, for example, Patent Document 1). The grinding wheel is rotated while the grinding surface of the grinding stone is brought into contact with the workpiece, thereby grinding the workpiece.

JP 2014-124690 A

After such a grinding wheel is mounted on the grinding device, the grinding wheel is dressed. Dressing the grinding wheel is an essential task performed to sharpen and true the grinding surface, but when this dressing is performed, processing by the grinding device is stopped, which leads to a decrease in productivity. Therefore, there has been a need to establish a method for dressing the grinding wheel without decreasing productivity.

Therefore, the object of the present invention is to provide a grinding wheel and a grinding method that can perform dressing without reducing productivity.

According to one aspect of the present invention, a grinding wheel for grinding a workpiece is provided, the grinding wheel having an annular wheel base and a plurality of grinding wheels arranged in a ring shape on one surface of the wheel base, the grinding wheels having a base portion having a mounting surface that is mounted on the wheel base, and a wear-promoting portion having a grinding surface that contacts the workpiece and is more susceptible to wear than the base portion.

Preferably, the brittleness of the wear accelerating portion is greater than the brittleness of the base portion. Also, preferably, the Vickers hardness of the wear accelerating portion is less than the Vickers hardness of the base portion.

Also, preferably, the wear promotion layer portion is made of the same material as the base portion, and a plurality of grooves are formed on the grinding surface side of the wear promotion portion. Also, preferably, the wear promotion portion is made of the same material as the base portion, and has a shape in which the volume decreases toward the grinding surface.

Also, preferably, the porosity of the wear-promoting portion is higher than the porosity of the base portion.

Also, preferably, the thickness of the wear-promoting portion in the direction from the grinding surface toward the base portion is 5 μm or more and 15 μm or less.

According to another aspect of the present invention, there is provided a grinding method for grinding a workpiece, comprising: a circular wheel base; and a plurality of grinding wheels arranged in a ring shape on one surface of the wheel base. The grinding wheels have a base portion having a mounting surface attached to the wheel base; and a grinding surface that contacts the workpiece and a wear-promoting portion that is more susceptible to wear than the base portion. The grinding method uses a grinding wheel having a base portion having a mounting surface attached to the wheel base and a wear-promoting portion that is more susceptible to wear than the base portion, and grinds the surface of the workpiece with the wear-promoting portion, and then grinds the workpiece with the base portion after the wear-promoting portion is gone.

A grinding wheel according to one aspect of the present invention has a base portion and a wear-promoting portion that is more susceptible to wear than the base portion, and is configured so that the wear-promoting portion comes into contact with the workpiece at the beginning of grinding the workpiece. Therefore, when grinding of the workpiece begins with the grinding wheel, the wear-promoting portion wears appropriately, and the grinding wheel is dressed as the workpiece is ground. Thus, according to one aspect of the present invention, a grinding wheel is provided that can be dressed without reducing productivity.

FIG. 1 is a perspective view showing a schematic diagram of a grinding apparatus. FIG. 2 is a perspective view showing a schematic diagram of a first example of a grinding wheel. FIG. 3 is a cross-sectional view illustrating a first example of a grinding wheel. FIG. 4 is an enlarged view of the grinding wheel of FIG. FIG. 5 is a side view showing a schematic view of the grinding wheel and the workpiece before grinding the workpiece. FIG. 6 is a side view showing a schematic view of the wear promotion portion being worn during grinding of the workpiece. FIG. 7 is a side view showing a state in which a wear-promoting portion is lost during grinding of a workpiece. FIG. 8 is a cross-sectional view illustrating a second example of the grinding wheel. FIG. 9 is an enlarged side view of the grinding wheel of FIG. FIG. 10 is a cross-sectional view illustrating a third example of the grinding wheel. FIG. 11 is an enlarged side view of the grinding wheel of FIG. FIG. 12 is a side view diagrammatically showing a grinding stone of a fourth example of the grinding wheel. FIG. 14 is a flow diagram showing a first example of a grinding method.

Below, an embodiment of a grinding wheel according to one aspect of the present invention will be described with reference to the attached drawings. First, an example of the configuration of a grinding device according to this embodiment will be described. FIG. 1 is a perspective view showing a grinding device 2 that grinds a workpiece 11. In FIG. 1, the X-axis direction (first horizontal direction, left-right direction of the grinding device 2) and the Y-axis direction (second horizontal direction, front-rear direction of the grinding device 2) are perpendicular to each other. Also, the Z-axis direction (processing feed direction, height direction of the grinding device 2, vertical direction, up-down direction) is perpendicular to the X-axis direction and the Y-axis direction.

The grinding device 2 includes a base 4 that supports or houses each of the components that make up the grinding device 2. An opening 4a is provided on the top surface side of the front end of the base 4, and a transport unit (transport mechanism) 6 that transports the workpiece 11 is provided inside the opening 4a. For example, a transport robot equipped with a robot hand (end effector) capable of holding the workpiece 11 is used as the transport unit 6.

Cassette installation areas 8A and 8B are provided on both sides of the transport unit 6. Cassettes 10A and 10B capable of accommodating multiple workpieces 11 are arranged on the cassette installation areas 8A and 8B, respectively. Cassettes 10A and 10B can respectively accommodate workpieces 11 to be processed by the grinding device 2 (workpieces 11 before processing) and workpieces 11 that have been processed by the grinding device 2 (workpieces 11 after processing).

For example, the workpiece 11 is a disk-shaped wafer made of a semiconductor material such as single crystal silicon, and has a front surface (first surface) 11a and a back surface (second surface) 11b that are generally parallel to each other. The workpiece 11 is partitioned into a number of rectangular regions by a number of streets (planned division lines) arranged in a lattice pattern so as to intersect with each other. In addition, each region partitioned by the streets on the front surface 11a of the workpiece 11 has a device formed therein, such as an integrated circuit (IC), a large scale integration (LSI), a light emitting diode (LED), or a micro electro mechanical systems (MEMS) device (not shown).

By dividing the workpiece 11 along the streets using a processing device such as a cutting device or a laser processing device, multiple device chips, each equipped with a device, are manufactured. In addition, before or after dividing the workpiece 11, the workpiece 11 is ground and thinned using a grinding device 2 to obtain a thinned device chip.

However, there are no restrictions on the type, material, size, shape, structure, etc. of the workpiece 11. For example, the workpiece 11 may be a substrate (wafer) made of a semiconductor other than silicon (GaAs, InP, GaN, SiC, etc.), glass, ceramics, resin, metal, etc. Furthermore, there are no restrictions on the type, number, shape, structure, size, arrangement, etc. of devices formed on the workpiece 11, and the workpiece 11 does not necessarily have to have any devices formed thereon.

Furthermore, the workpiece 11 may be a package substrate such as a CSP (Chip Size Package) substrate or a QFN (Quad Flat Non-leaded package) substrate. For example, a package substrate is formed by sealing multiple device chips mounted on a specific substrate with a resin layer (molding resin). By dividing and individualizing the package substrate, multiple package devices each including multiple packaged device chips are manufactured.

An alignment mechanism 12 is provided diagonally behind the opening 4a. The workpieces 11 stored in the cassettes 10A and 10B are transported to the alignment mechanism 12 by the transport unit 6. The alignment mechanism 12 then clamps the workpieces 11 and positions them in a predetermined position.

A transport unit (transport mechanism, loading arm) 14 that transports the workpiece 11 is provided adjacent to the alignment mechanism 12. For example, the transport unit 14 includes a suction pad that holds the top side of the workpiece 11 by suction. After the transport unit 14 holds the workpiece 11 that has been aligned by the alignment mechanism 12 with the suction pad, it rotates the suction pad to transport the workpiece 11 backward.

A disk-shaped turntable 16 is provided behind the transport unit 14. A rotational drive source (not shown), such as a motor, is connected to the turntable 16 to rotate the turntable 16 around a rotation axis that is generally parallel to the Z-axis direction.

On the turntable 16, multiple chuck tables (holding tables) 18 for holding the workpieces 11 are provided. Figure 1 shows an example in which three chuck tables 18 are arranged at approximately equal intervals (120° intervals) around the circumference of the turntable 16. However, there is no limit to the number of chuck tables 18.

The turntable 16 shown in FIG. 1 rotates clockwise and counterclockwise in a plan view. This causes each chuck table 18 to be positioned in sequence through the transfer position A, the rough grinding position (first grinding position) B, the finish grinding position (second grinding position) C, and then back to the transfer position A.

Thickness gauges 26 for measuring the thickness of the workpiece 11 held by the chuck table 18 are provided near the rough grinding position B and near the finish grinding position C. For example, the thickness gauges 26 include a first height gauge (first height gauge) for measuring the height of the top surface of the workpiece 11 held by the chuck table 18, and a second height gauge (second height gauge) for measuring the height of the top surface of the chuck table 18.

Columnar support structures 28A and 28B are disposed behind the rough grinding position B and the finish grinding position C, respectively. A moving unit (moving mechanism) 30A is provided on the front side of the support structure 28A, and a moving unit (moving mechanism) 30B is provided on the front side of the support structure 28B.

Each of the moving units 30A and 30B has a pair of guide rails 32 arranged along the Z-axis direction. A flat moving plate 34 is attached to the pair of guide rails 32 so as to be slidable along the guide rails 32.

A nut portion (not shown) is provided on the rear side (back side) of the moving plate 34. A ball screw 36 is disposed between the pair of guide rails 32 along the Z-axis direction and is screwed into this nut portion. A pulse motor 38 that rotates the ball screw 36 is connected to the end of the ball screw 36. When the ball screw 36 is rotated by the pulse motor 38, the moving plate 34 moves along the Z-axis direction.

A grinding unit (rough grinding unit) 40A that performs rough grinding on the workpiece 11 is attached to the moving plate 34 of the moving unit 30A. The grinding unit 40A grinds the workpiece 11 held by the chuck table 18 positioned at the rough grinding position B. A grinding unit (finish grinding unit) 40B that performs finish grinding on the workpiece 11 is attached to the moving plate 34 of the moving unit 30B. The grinding unit 40B grinds the workpiece 11 held by the chuck table 18 positioned at the finish grinding position C.

Each of the grinding units 40A and 40B has a housing 42 formed in a hollow cylindrical shape. The housing 42 is fixed to the front side (surface side) of the moving plate 34. The housing 42 contains a cylindrical spindle 44 (see FIG. 5) arranged along the Z-axis direction, and the tip (lower end) of the spindle 44 is exposed from the housing 42. A motor 46 that rotates the spindle 44 is connected to the base end (upper end) of the spindle 44, and a disk-shaped wheel mount 48 made of metal or the like is fixed to the tip of the spindle 44.

A grinding wheel (rough grinding wheel) 50A for rough grinding is attached to the underside of the wheel mount 48 of the grinding unit 40A. Meanwhile, a grinding wheel (finish grinding wheel) 50B for finish grinding is attached to the underside of the wheel mount 48 of the grinding unit 40B. The grinding wheels 50A and 50B are processing tools that can be attached to and detached from the wheel mount 48 and grind the workpiece 11, and are fixed to the wheel mount 48 by a fastening device such as a fastening bolt. In this way, the grinding wheels 50A and 50B are attached to the tip of the spindle 44. Details of the grinding wheels 50A and 50B will be described later.

The moving unit 30A moves the grinding unit 40A up and down along the Z-axis direction, thereby moving the chuck table 18 and the grinding wheel 50A, which are positioned at the rough grinding position B, closer to and farther away from each other along the Z-axis direction. Similarly, the moving unit 30B moves the grinding unit 40B up and down along the Z-axis direction, thereby moving the chuck table 18 and the grinding wheel 50B, which are positioned at the finish grinding position C, closer to and farther away from each other along the Z-axis direction.

As shown in FIG. 1, a transport unit (transport mechanism, unloading arm) 66 that transports the workpiece 11 is provided at a position adjacent to the transport unit 14 in the X-axis direction. For example, the transport unit 66 includes a suction pad that holds the top side of the workpiece 11 by suction. The transport unit 66 holds the workpiece 11 held by the chuck table 18 arranged at transport position A with the suction pad, and then rotates the suction pad to transport the workpiece 11 forward.

A cleaning unit (cleaning mechanism, cleaning device) 68 that cleans the workpiece 11 is provided in front of the transport unit 66. The cleaning unit 68 cleans the workpiece 11 transported from the chuck table 18 by the transport unit 66. For example, the cleaning unit 68 includes a spinner table that holds and rotates the workpiece 11, and a nozzle that supplies cleaning liquid (pure water, etc.) to the workpiece 11 held by the spinner table.

The grinding device 2 also includes a controller (control unit, control section, control device) 64 connected to each of the components constituting the grinding device 2 (the transport unit 6, the alignment mechanism 12, the transport unit 14, the turntable 16, the chuck table 18, the thickness gauge 26, the moving units 30A and 30B, the grinding units 40A and 40B, the transport unit 66, the cleaning unit 68, etc.). The controller 64 controls the operation of the grinding device 2 by outputting control signals to each of the components of the grinding device 2.

For example, the controller 64 is configured by a computer and includes a calculation unit that performs calculations necessary for the operation of the grinding device 2, and a storage unit that stores various information (data, programs, etc.) used in the operation of the grinding device 2. The calculation unit includes a processor such as a CPU (Central Processing Unit). The storage unit includes memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory).

When the workpiece 11 is processed by the grinding device 2, first, a cassette 10A or cassette 10B containing multiple workpieces 11 is placed on the cassette installation area 8A or cassette installation area 8B. Then, the transport unit 6 transports the workpiece 11 from the cassette 10A or cassette 10B to the alignment mechanism 12, which aligns the workpiece 11. Thereafter, the transport unit 14 transports the workpiece 11 to the chuck table 18 located at the transport position A, and the workpiece 11 is held by the chuck table 18.

Next, the turntable 16 rotates, and the chuck table 18 holding the workpiece 11 is positioned at the rough grinding position B. The workpiece 11 is then ground by the grinding wheel 50A attached to the grinding unit 40A. This results in rough grinding of the workpiece 11.

Next, the turntable 16 rotates, and the chuck table 18 holding the workpiece 11 is positioned at the finish grinding position C. The workpiece 11 is then ground by the grinding wheel 50B attached to the grinding unit 40B. This completes the finish grinding of the workpiece 11.

When grinding of the workpiece 11 is completed, the turntable 16 rotates and the chuck table 18 holding the workpiece 11 is again positioned at the transport position A. The workpiece 11 is then transported from the chuck table 18 to the cleaning unit 68 by the transport unit 66, and is cleaned by the cleaning unit 68. After cleaning, the workpiece 11 is transported by the transport unit 6 and is again stored in the cassette 10A or cassette 10B.

Next, the grinding wheels 50A and 50B will be described. Note that, in the following, the grinding wheel 50A for rough grinding will be described as an example, but the grinding wheel 50B for finish grinding can also be configured in a similar manner. Figure 2 is a perspective view showing a first example of the grinding wheel, Figure 3 is a cross-sectional view showing a first example of the grinding wheel, and Figure 4 is an enlarged view of the grinding wheel in Figure 3.

As shown in FIG. 2, the grinding wheel 50A has an annular wheel base 52. The wheel base 52 is made of a metal such as aluminum or stainless steel, and is formed to have approximately the same diameter as the wheel mount 48. In addition, a plurality of grinding stones 54 are fixed to the underside of the wheel base 52. For example, the grinding stones 54 are formed in a rectangular parallelepiped shape and are arranged in a ring shape at approximately equal intervals along the circumferential direction of the wheel base 52.

As shown in FIG. 4, the grinding wheel 54 has a base portion 56 having a mounting surface 58 that is attached to the wheel base 52, and a wear-promoting portion 60 that faces the opposite side to the mounting surface 58 and has a grinding surface 62 that contacts the workpiece 11. The base portion 56 is formed, for example, in a rectangular parallelepiped shape. The wear-promoting portion 60 is configured to be more susceptible to wear than the base portion 56.

For example, by using a material that is more brittle than the material of the base portion 56 as the material for the wear acceleration portion 60, the wear acceleration portion 60 becomes more susceptible to wear than the base portion 56. Alternatively, by using a material that has a lower Vickers hardness than the material of the base portion 56 as the material for the wear acceleration portion 60, the wear acceleration portion 60 becomes more susceptible to wear than the base portion 56.

On the other hand, when the material of the base portion 56 and the material of the wear accelerating portion 60 are the same, the wear accelerating portion 60 is configured to have a shape whose volume decreases toward the grinding surface 62, so that the wear accelerating portion 60 is more susceptible to wear than the base portion 56. For example, when the shape of the wear accelerating portion 60 is a dome shape or a frustum shape whose volume on the grinding surface 62 side is smaller, the wear accelerating portion 60 is more susceptible to wear than the base portion 56. Similarly, when the porosity of the wear accelerating portion 60 is greater than the porosity of the base portion 56, the wear accelerating portion 60 is more susceptible to wear than the base portion 56.

The material of the base portion 56 and the wear accelerating portion 60 is not particularly limited. For example, the base portion 56 and the wear accelerating portion 60 are made of a material including abrasive grains such as diamond or cBN (cubic boron nitride) and a bonding material (bond material) such as a metal bond, a resin bond, or a vitrified bond that fixes the abrasive grains. The number and arrangement of the grinding wheels 54 can also be set arbitrarily.

The thickness a of the wear accelerating portion 60 is preferably set to a thickness such that the wear accelerating portion 60 is completely lost before grinding of one workpiece 11 is completed. By setting the thickness a of the wear accelerating portion 60 to such a thickness, one workpiece 11 is ground by both the wear accelerating portion 60 and the base portion 56. For example, the thickness a of the wear accelerating portion 60 is preferably 5 μm or more and 15 μm or less.

Next, the action and effect of the present embodiment, which is achieved by configuring the wear-promoting portion 60 to be more susceptible to wear than the base portion 56, will be described. FIG. 5 is a side view that shows the grinding wheel 50A and the workpiece 11 before grinding the workpiece 11. FIG. 6 is a side view that shows the wear-promoting portion 60 as the workpiece 11 is ground, and FIG. 7 is a side view that shows the wear-promoting portion 60 as the workpiece 11 is ground.

As shown in FIG. 5, when the motor 46 is driven, the spindle 44 and the grinding wheel 50A rotate around a rotation axis that is generally parallel to the Z-axis direction. This causes each of the grinding wheels 54 to rotate along a circular rotation path (orbit) centered on the rotation axis of the spindle 44 and the grinding wheel 50A.

As shown in FIG. 5, when the grinding wheel 50A is attached to the wheel mount 48, if a foreign object is present between the wheel mount 48 and the grinding wheel 50A, a gap c will be created between the wheel mount 48 and the grinding wheel 50A. As a result, the grinding surface 62 of the grinding wheel 54 will be inclined relative to the surface (grinding surface) 11a of the workpiece 11. In other words, the actual grinding surface 62 will be inclined relative to the grinding surface in an ideal state in which the surface 11a of the workpiece 11 is properly ground, and a deviation of a deviation b will be created between the actual grinding surface 62 and the ideal grinding surface.

When the workpiece 11 is ground in a state where such a deviation b exists, some parts of the surface 11a of the workpiece 11 are in contact with the grinding wheel 54 and some are not. This may result in a decrease in the quality of the workpiece 11. More specifically, for example, there is a risk that the variation in surface roughness between multiple workpieces 11 and the in-plane variation in surface roughness within a single workpiece 11 will increase.

As shown in FIG. 6, the grinding wheel 50A of this embodiment is configured so that the wear accelerating portion 60 comes into contact with the workpiece 11 at the beginning of grinding the workpiece 11. Therefore, when grinding of the workpiece is started by the grinding wheel 50A, the wear accelerating portion 60 wears appropriately, and the grinding wheel 50A is dressed as the workpiece 11 is ground. As a result, the bottom surface of the grinding wheel 54 approaches an ideal grinding surface, and the effect of the deviation amount b is substantially eliminated.

In conventional grinding devices and methods, in order to dress (sharpen, true) the grinding wheel, a process was required in which a dummy workpiece was prepared and ground before grinding the workpiece. In contrast, when the grinding wheel 50A of this embodiment is used, as described above, special work for dressing the grinding wheel 50A is not required, and dressing is performed simultaneously with grinding the workpiece 11. Therefore, the grinding wheel of this embodiment can prevent a decrease in productivity.

The grinding wheel 50A of this embodiment is particularly effective in cases where the grinding wheel 50A is replaced frequently and dressing work is required frequently, for example, when grinding a workpiece 11 made of a hard material. In addition, as described above, in the grinding wheel 50A of this embodiment, the wear-promoting portion 60 is configured to a thickness that can be completely removed by grinding one workpiece 11, so that after the workpiece is ground by the wear-promoting portion 60, the same workpiece 11 is subsequently ground by the base portion 56. Therefore, the quality of the workpiece 11 can be maintained at the same level as before.

The thickness of the wear accelerating portion 60 in the direction from the grinding surface 62 toward the base portion 56 (thickness a in FIG. 4) is preferably adjusted according to the mounting tolerance of the grinding wheel 50A. For example, the thickness of the wear accelerating portion 60 is preferably set to be equal to or greater than the mounting tolerance. If the thickness of the wear accelerating portion 60 is too large, the grinding of one workpiece 11 is completed without the wear accelerating portion 60 being completely lost. In this case, the quality of the workpiece 11 ground only by the wear accelerating portion 60 is likely to differ from that of the workpiece 11 ground by the base portion 56 after the wear accelerating portion 60 is completely lost. Therefore, it is preferable that the thickness of the wear accelerating portion 60 is set to a thickness that is completely lost before the grinding of one workpiece 11 is completed.

This allows the wear-promoting portion 60 to be configured to a thickness that allows it to be completely removed by grinding one workpiece 11, and after the workpiece 11 is ground by the wear-promoting portion 60, the same workpiece 11 is subsequently ground by the base portion 56. As a result, it becomes easier to maintain consistent quality among multiple workpieces 11.

Another aspect of the grinding wheel 54 will now be described. FIG. 8 is a cross-sectional view showing a schematic diagram of a second example of the grinding wheel, and FIG. 9 is an enlarged side view of the grinding wheel of FIG. 8. As shown in FIGS. 8 and 9, in this embodiment, a plurality of grooves are provided on the grinding surface 62 side of the wear accelerating portion 60. By having the wear accelerating portion 60 have such a shape, the volume of the wear accelerating portion 60 is smaller than that of the base portion 56, and the wear accelerating portion 60 is more easily worn than the base portion 56.

Figure 10 is a cross-sectional view showing a schematic diagram of a third example of a grinding wheel, and Figure 11 is an enlarged side view of the grinding wheel of Figure 10. As shown in Figures 10 and 11, in this embodiment, the wear accelerating portion 60 has a dome shape. In other words, the wear accelerating portion 60 has a shape that tapers toward the grinding surface 62 so that the volume decreases toward the grinding surface 62. By having the wear accelerating portion 60 have such a shape, the volume of the wear accelerating portion 60 is smaller than the base portion 56, particularly on the grinding surface 62 side, and the grinding surface 62 side of the wear accelerating portion 60 is more easily worn than the base portion 56.

Figure 12 is a side view showing a grinding stone of a fourth example of a grinding wheel. As shown in Figure 12, in this embodiment, the wear accelerating portion 60 has a quadrangular pyramid shape. In other words, the wear accelerating portion 60 has a shape that tapers toward the grinding surface 62 so that the volume decreases toward the grinding surface 62. By having the wear accelerating portion 60 have such a shape, the volume of the wear accelerating portion 60 is smaller than the base portion 56, particularly on the grinding surface 62 side, and the grinding surface 62 side of the wear accelerating portion 60 is more easily worn than the base portion 56.

Next, a grinding method according to one aspect of the present invention will be described. FIG. 13 is a flow diagram showing a first example of the grinding method. As shown in FIG. 13, the grinding method of this embodiment includes a step (S1) of attaching the grinding wheel 50A to the wheel mount 48, a step (S2) of transporting the workpiece 11 to the rough grinding position B, a first grinding step (S3), and a second grinding step (S4).

However, if the grinding wheel 50B for finish grinding is configured similarly to the grinding wheel 50A for rough grinding described above, the grinding wheel 50A in step S1 can be replaced with the grinding wheel 50B, and the rough grinding position B in step S2 can be replaced with the finish grinding position C.

In the grinding method of this embodiment, the grinding device 2 according to one aspect of the present invention described above is used. When grinding of the workpiece 11 is started, the grinding device 2 grinds the workpiece 11 with the wear-promoting portion 60 of the grinding wheel 54 in the first grinding step (S3). Since the wear-promoting portion 60 is configured to be easily worn, dressing of the grinding wheel 50A progresses simultaneously with grinding of the workpiece 11. Then, even after the wear-promoting portion 60 is worn away, the grinding device 2 continues to grind the workpiece 11 with the base portion 56 of the grinding wheel 54 in the second grinding step (S4).

As described above, this embodiment provides a grinding method that allows dressing to be performed without reducing productivity.

In addition, the structures, methods, etc. according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention.

11 Workpiece 11a Surface (first surface)
11b Back side (second surface)
2 Grinding device 4 Base 4a Opening 6 Transport unit (transport mechanism)
8A, 8B Cassette installation area 10A, 10B Cassette 12 Alignment mechanism
14 Transport unit (transport mechanism, loading arm)
16 Turntable 18 Chuck table (holding table)
26 Thickness measuring device 28A, 28B Support structure 30A, 30B Moving unit (moving mechanism)
32 Guide rail 34 Moving plate 36 Ball screw 38 Pulse motor 40A Grinding unit (rough grinding unit)
40B Grinding unit (finish grinding unit)
42 Housing 44 Spindle 48 Wheel mount 50A Grinding wheel (coarse grinding wheel)
50B Grinding wheel (finish grinding wheel)
52 Wheel base 54 Grinding wheel 56 Base portion of grinding wheel 58 Mounting surface of grinding wheel to wheel base 60 Wear promoting portion of grinding wheel 62 Grinding surface of grinding wheel 64 Controller (control unit, control unit, control device)
66 Transport unit (transport mechanism, unloading arm)
68 Cleaning unit (cleaning mechanism, cleaning device)

Claims (8)

A grinding wheel for grinding a workpiece, comprising:
A circular wheel base;
a plurality of grinding wheels arranged in an annular shape on one surface side of the wheel base;
The grinding wheel is
a base portion having a mounting surface to be mounted on the wheel base;
The grinding wheel has a grinding surface that contacts the workpiece, and a wear-promoting portion that is more susceptible to wear than the base portion. The grinding wheel according to claim 1, wherein the brittleness of the wear-promoting portion is greater than the brittleness of the base portion. The grinding wheel according to claim 1, wherein the Vickers hardness of the wear-promoting portion is less than the Vickers hardness of the base portion. The wear promoting portion is made of the same material as the base portion,
2. The grinding wheel according to claim 1, wherein the wear promoting portion has a plurality of grooves formed on the grinding surface side. The grinding wheel according to claim 1, wherein the wear promoting portion is made of the same material as the base portion and has a shape in which the volume decreases toward the grinding surface. The grinding wheel according to claim 1, wherein the porosity of the wear-promoting portion is higher than the porosity of the base portion. The grinding wheel according to claim 1, wherein the thickness of the wear-promoting portion in the direction from the grinding surface toward the base portion is 5 μm or more and 15 μm or less. A grinding method for grinding a workpiece, comprising the steps of:
a grinding wheel having a circular wheel base and a plurality of grinding wheels arranged in a ring shape on one side of the wheel base, the grinding wheels having a base portion having a mounting surface mounted on the wheel base and a wear-promoting portion having a grinding surface that contacts the workpiece and is more susceptible to wear than the base portion, the surface of the workpiece being ground by the wear-promoting portion;
After the wear-promoting portion is removed, the workpiece is ground with the base portion.

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