JP7477330B2 - Grinding device and method for grinding workpiece - Google Patents

Description

The present invention relates to a grinding device and a method for grinding a workpiece.

A method is known in which a grinding wheel, which has grinding stones arranged in a ring, is rotated and pressed against a disk-shaped workpiece such as a semiconductor wafer held on a holding table using a feed mechanism to grind the workpiece (see Patent Document 1).

Patent No. 5025200

For example, there is a need to grind a workpiece having a metal or resin film formed on a silicon substrate from the film side. However, with the method of Patent Document 1, there is a problem that the metal or resin film has high viscosity, so some of it peels off and adheres to the grinding surface of the grinding wheel, making it impossible to perform stable grinding.

The present invention was made in consideration of these problems, and its purpose is to provide a grinding device and a method for grinding a workpiece that can stably grind from the film side even when a highly viscous film is formed.

In order to solve the above-mentioned problems and achieve the object, the grinding apparatus of the present invention is a grinding apparatus comprising: a holding table having a holding surface for holding a workpiece having a film formed on one surface of a substrate such that the surface on which the film is formed is exposed; a grinding unit having a grinding wheel having a grinding stone for grinding the workpiece held on the holding surface from the surface on which the film is formed and a drive source for rotating the grinding wheel; a grinding feed unit for feeding the grinding unit in a direction perpendicular to the holding table; a grinding state changing unit for changing the state between a parallel state and a grinding surface of the grinding stone and a non-parallel state; and a control unit for controlling the grinding state changing unit, the control unit rotating the holding table and feeding the grinding wheel while rotating it to grind the workpiece held on the holding surface. When grinding a workpiece, the grinding state change unit is operated to make the holding surface and the grinding surface of the grinding wheel non-parallel, and grinding is started with the grinding surface in contact with a part of the film, and the workpiece is ground while increasing the area of the workpiece in contact with the grinding surface in accordance with the grinding feed of the grinding wheel, until a predetermined amount of the film is ground away , and a grinding amount, which is the thickness by which the workpiece has been ground, or a base material exposure ratio, which is the ratio of the area of the exposed base material of the workpiece to the total area of the surface side of the workpiece being ground, is detected, and by determining that the detected grinding amount or base material exposure ratio is equal to or greater than a predetermined amount, the grinding feed unit is switched to control so as to perform grinding feed while controlling the grinding state change unit so that the holding surface and the grinding surface of the grinding wheel are gradually changed from the non-parallel state to a parallel state.

In order to solve the above-mentioned problems and achieve the object, the present invention provides a method for grinding a workpiece, comprising: a holding table having a holding surface for holding the workpiece; a grinding unit having a grinding wheel having a grinding stone for grinding the workpiece held on the holding surface and a drive source for rotating the grinding wheel; a grinding feed unit for feeding the grinding unit in a direction perpendicular to the holding table; a grinding state changing unit for changing the state between a parallel state and a non-parallel state between the holding surface and the grinding surface of the grinding stone; and a control unit for controlling the grinding state changing unit, the method comprising: a holding step of holding the workpiece on the holding surface so that the surface on which the film is formed is exposed, the holding step of holding the workpiece on the holding surface so that the surface on which the film is formed is exposed, and a holding step of holding the workpiece on the holding surface so that the film is formed. a first grinding step in which the holding surface and the grinding surface of the grinding wheel are made non-parallel so as to be a predetermined distance apart, grinding is started in a state in which the grinding surface is in contact with a portion of the film, and the workpiece is ground while the area of the workpiece in contact with the grinding surface is gradually increased in accordance with the grinding feed of the grinding wheel; and a second grinding step in which, when a predetermined amount of the film has been ground off in the first grinding step, the holding surface and the grinding surface of the grinding wheel are gradually changed from the non-parallel state to a parallel state while the grinding feed is performed, thereby grinding the workpiece, wherein the control unit detects a grinding amount, which is the thickness by which the workpiece has been ground, or a base material exposure ratio, which is the ratio of the area of the workpiece's base material exposed to the total area of the surface side of the workpiece that is ground, and switches from the first grinding step to the second grinding step by determining that the detected grinding amount or base material exposure ratio is equal to or greater than a predetermined amount .

The present invention allows stable grinding from the film side even when a highly viscous film is formed.

FIG. 1 is a perspective view showing an example of the configuration of a grinding device according to a first embodiment. FIG. 2 is a cross-sectional view for explaining an example of the function of the main part of the grinding device of FIG. FIG. 3 is a cross-sectional view for explaining another example of the function of the main parts of the grinding device of FIG. FIG. 4 is a top view showing the state of a workpiece during grinding using the function of FIG. FIG. 5 is a top view showing the state of a workpiece during grinding using the function of FIG. FIG. 6 is a diagram showing an example of processing sequence data stored in the control unit of the grinding apparatus of FIG. FIG. 7 is a flowchart showing an example of a processing procedure of the method for grinding a workpiece according to the first embodiment. FIG. 8 is a cross-sectional view illustrating the first grinding step of FIG. FIG. 9 is a cross-sectional view illustrating the second grinding step of FIG. FIG. 10 is a cross-sectional view illustrating a first grinding step of the grinding method for a workpiece according to the second embodiment. FIG. 11 is a flowchart showing an example of a processing procedure of a method for grinding a workpiece according to the third embodiment. FIG. 12 is a perspective view illustrating an example of the configuration of a grinding device according to the fourth embodiment. FIG. 13 is a flowchart showing a first example of a processing procedure of the method for grinding a workpiece according to the fourth embodiment. FIG. 14 is a flowchart showing a second example of the processing procedure of the method for grinding a workpiece according to the fourth embodiment. FIG. 15 is a flowchart showing a third example of the processing procedure of the method for grinding a workpiece according to the fourth embodiment. FIG. 16 is a flowchart showing a fourth example of the processing procedure of the method for grinding a workpiece according to the fourth embodiment.

The following describes in detail the form (embodiment) for carrying out the present invention with reference to the drawings. The present invention is not limited to the contents described in the following embodiment. The components described below include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. Various omissions, substitutions, or modifications of the configuration can be made without departing from the spirit of the present invention.

[Embodiment 1]
A grinding device 1 and a method for grinding a workpiece according to a first embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view showing a configuration example of the grinding device 1 according to the first embodiment. As shown in Fig. 1, the grinding device 1 according to the first embodiment includes a holding table 10, a grinding unit 20, a grinding feed unit 30, a grinding state changing unit 40, a grinding amount detection unit 50, and a control unit 60.

In the first embodiment, the workpiece 200 to be ground by the grinding device 1 is configured to have a base material 201 and a film 202 formed on one side of the base material 201, as shown in FIG. 1. In the first embodiment, the base material 201 is, for example, a disk-shaped silicon, such as a disk-shaped semiconductor wafer or an optical device wafer. A device may be formed in an area partitioned by a plurality of planned division lines formed in a lattice shape on either side. In the first embodiment, the film 202 is made of a material having a higher viscosity than the base material 201, and is, for example, a metal film such as Ni, Al, Ti, Pt, or Cu, or a resin film such as resist, ABF resin, or PI (Poly-Imide). In the first embodiment, the film 202 has a thickness of 10 μm or less when it is a metal film. In the first embodiment, the film 202 has a thickness of 3 μm or more and 60 μm or less when it is a resin film. The workpiece 200 has an adhesive tape 205 attached to the side opposite the side on which the film 202 is formed.

The holding table 10 holds the workpiece 200 on the holding surface 11 with the surface on which the film 202 is formed facing upward so as to expose it. The holding table 10 is disk-shaped, with a flat holding surface 11 formed on the upper surface thereof for holding the workpiece 200, a disk-shaped suction section made of porous ceramics or the like having a large number of porous holes, and a frame body for fixing the suction section by fitting it into a recess in the center of the upper surface. The holding surface 11 is formed approximately parallel to the XY plane, which is a horizontal plane. The holding table 10 is provided so as to be movable in the X-axis direction, which is one horizontal direction, by an X-axis moving unit (not shown), and to be rotatable around a rotation axis 19 (see Figures 2, 3, etc.) approximately along the Z axis by a rotary drive source (not shown). The suction section of the holding table 10 is connected to a vacuum suction source (not shown) via a vacuum suction path (not shown), and the entire holding surface 11 suctions and holds the workpiece 200.

As shown in FIG. 1, the grinding unit 20 includes a grinding wheel 22 having grinding stones 21 arranged in a ring shape, a spindle 23, and a servo motor 24. The grinding stone 21 is arranged below the grinding wheel 22 and has a grinding surface 25 on the lower side. In the first embodiment, the grinding stone 21 has a relatively large abrasive grain size, for example, a grain size of #320 (320th) or #600 (600th), and is used for rough grinding of a workpiece 200 having a silicon base material 201. The grinding wheel 22 is attached to the lower end of the spindle 23 and rotates with the rotation of the spindle 23. The spindle 23 supports the grinding wheel 22 rotatably around a rotation axis 29 (see FIG. 2, FIG. 3, etc.) that is approximately parallel to the Z-axis direction that is parallel to the vertical direction. The servo motor 24 functions as a rotation drive source that supplies rotational power to the spindle 23.

The grinding feed unit 30 is attached to the grinding unit 20 and feeds the grinding unit 20 for grinding in the vertical direction (Z-axis direction), which is a direction roughly perpendicular to the holding surface 11 of the holding table 10.

When both the rotation axis 19 of the holding surface 11 of the holding table 10 and the rotation axis 29 of the grinding surface 25 of the grinding wheel 21 are held parallel to the XY plane, they are positioned offset from each other in the XY plane.

While rotating the grinding wheel 22, the grinding unit 20 presses the workpiece 200 held on the holding table 10 against the surface on which the film 202 is formed, along the Z-axis direction, which is parallel to the vertical direction, with the grinding feed unit 30, thereby grinding the workpiece 200 from the surface on which the film 202 is formed.

The grinding state change unit 40 changes the relationship between the holding surface 11 of the holding table 10 and the grinding surface 25 of the grinding wheel 21 to change the grinding state of the workpiece 200 on the holding table 10 with the grinding wheel 21. The grinding state change unit 40 can change the holding surface 11 of the holding table 10 and the grinding surface 25 of the grinding wheel 21 between a parallel state in which they are parallel to each other and a non-parallel state in which they are not parallel to each other.

In the first embodiment, the grinding state change unit 40 includes a grinding surface tilting unit 40-1 and a holding surface tilting unit 40-2, as shown in FIG. 1. The grinding surface tilting unit 40-1 is provided in the grinding unit 20, and tilts the grinding surface 25 of the grinding wheel 21 by rotating the grinding unit 20 about the X-axis. The holding surface tilting unit 40-2 is provided in the holding table 10, and tilts the holding surface 11 of the holding table 10 by rotating the holding table 10 about the X-axis.

Figure 2 is a cross-sectional view for explaining an example of the function of the main part of the grinding device 1 in Figure 1. Figure 3 is a cross-sectional view for explaining another example of the function of the main part of the grinding device 1 in Figure 1. Figure 2 shows a state in which the grinding surface 25 of the grinding wheel 21 is inclined by an angle θ1 with respect to the holding surface 11 of the holding table 10 in a direction in which the area vertically facing the outside of the holding surface 11 of the holding table 10 is closer to the holding surface 11 of the holding table 10 than the area vertically facing the inside of the holding surface 11. Figure 3 shows a state in which the grinding surface 25 of the grinding wheel 21 is inclined by an angle θ2 with respect to the holding surface 11 of the holding table 10 in a direction in which the area vertically facing the inside of the holding surface 11 of the holding table 10 is closer to the holding surface 11 of the holding table 10 than the area vertically facing the outside of the holding surface 11, that is, in a direction opposite to the state shown in Figure 2.

In the first embodiment, the inclination angles θ1 and θ2 of the grinding surface 25 of the grinding wheel 21 relative to the holding surface 11 of the holding table 10 can be determined according to the thickness of the film 202. Specifically, the inclination angles θ1 and θ2 can be determined so that the difference in distance (inclination height) between the closest position on the grinding surface 25 of the grinding wheel 21 from the holding surface 11 of the holding table 10 and the furthest position from the holding surface 11 of the holding table 10 is twice the thickness of the film 202. In other words, the inclination height is the difference in height between the center and the outer edge of the holding table 10. For example, if the film 202 is 10 μm, the inclination angles θ1 and θ2 can be determined so that the inclination height is 20 μm.

The inclination of the grinding surface 25 of the grinding wheel 21 relative to the holding surface 11 of the holding table 10 may be formed by inclining the grinding unit 20 using the grinding surface inclination unit 40-1, or by inclining the holding surface 11 of the holding table 10 using the holding surface inclination unit 40-2, or both the grinding surface inclination unit 40-1 and the holding surface inclination unit 40-2 may be used.

As shown in Figures 1, 2, and 3, the grinding amount detection unit 50 is provided near the outer periphery of the holding surface 11 of the holding table 10. In the first embodiment, the grinding amount detection unit 50 is a contact-type height detection device, and includes contact-type probes 51 and 52 that detect the height of the contact position.

When the workpiece 200 is held on the holding surface 11 of the holding table 10, the probe 51 detects the height of the holding surface 11 by contacting the holding surface 11 from above in an area outside the outer edge of the workpiece 200. When the workpiece 200 is held on the holding surface 11 of the holding table 10, the probe 52 detects the height of the upper surface of the workpiece 200 by contacting the workpiece 200 from above in an area slightly inside the outer edge of the workpiece 200. The grinding amount detection unit 50 detects the thickness of the workpiece 200 in an area slightly inside the outer edge of the workpiece 200 based on the height information detected by the probes 51 and 52, and transmits the detected thickness information of the workpiece 200 to the control unit 60.

In the first embodiment, the grinding amount detection unit 50 is provided with contact probes 51, 52, but the present invention is not limited to this. For example, the grinding amount detection unit 50 may be configured to irradiate the inside and outside of the outer edge of the workpiece 200 with laser light of a wavelength that is reflected by the holding surface 11 and the workpiece 200, receive interference waves of the laser light reflected from both, and detect the thickness of the workpiece 200 in a region slightly inside the outer edge of the workpiece 200 based on the received interference waves.

Figure 4 is a top view showing the state of the workpiece 200 being ground using the function of Figure 2. Figure 5 is a top view showing the state of the workpiece 200 being ground using the function of Figure 3. When the grinding device 1 performs a grinding process by pressing the surface side of the workpiece 200 held on the holding table 10 on which the film 202 is formed with the grinding feed unit 30 along the Z-axis direction parallel to the vertical direction in the state shown in Figure 2, the workpiece 200 is ground from the outer periphery as shown in Figure 4, and the film 202 is removed from the outer periphery to expose the base material 201. When the grinding device 1 continues the grinding process in the state shown in Figure 2, the area where the film 202 is removed and the base material 201 is exposed expands from the outer periphery of the workpiece 200 toward the center, and the area where the film 202 remains shrinks toward the center.

When the grinding device 1 performs a grinding process by pressing the surface of the workpiece 200 held on the holding table 10 on which the film 202 is formed with the grinding feed unit 30 along the Z-axis direction parallel to the vertical direction, the workpiece 200 is ground from the inner circumference side as shown in FIG. 5, and the film 202 is removed from the inner circumference side to expose the base material 201. When the grinding device 1 continues the grinding process in the state shown in FIG. 3, the area where the film 202 is removed and the base material 201 is exposed expands from the central area of the workpiece 200 toward the outer circumference side, and accordingly the area where the film 202 remains shrinks toward the outer circumference side.

The control unit 60 controls each component of the grinding device 1 and causes the grinding device 1 to perform each operation related to each process of the grinding method for the workpiece 200 according to the first embodiment. In the first embodiment, the control unit 60 includes a computer system. The control unit 60 has an arithmetic processing device having a microprocessor such as a CPU (central processing unit), a storage device having a memory such as a ROM (read only memory) or a RAM (random access memory), and an input/output interface device. The arithmetic processing device performs arithmetic processing according to a computer program stored in the storage device, and outputs a control signal for controlling the grinding device 1 to each component of the grinding device 1 via the input/output interface device.

The control unit 60 controls the grinding feed unit 30 to move the grinding unit 20 away from or close to the holding table 10. The control unit 60 also controls the grinding feed unit 30 to move the grinding unit 20 close to the holding table 10, thereby grinding and feeding the grinding wheel 22 of the grinding unit 20 to the workpiece 200 on the holding table 10. The control unit 60 also obtains information on the grinding feed amount from the grinding feed unit 30.

The control unit 60 controls the grinding state change unit 40 to control the inclination angle of the grinding surface 25 of the grinding wheel 21 relative to the holding surface 11 of the holding table 10, and acquires information on this inclination angle. The control unit 60 controls the grinding amount detection unit 50 continuously or at regular intervals during grinding by the grinding unit 20 to detect the thickness of the workpiece 200 in an area slightly inside the outer edge of the workpiece 200, and acquires information on the thickness of the workpiece 200 in an area slightly inside the outer edge of the workpiece 200 detected by the grinding amount detection unit 50.

The control unit 60 calculates the amount of grinding in the area slightly inside the outer edge of the workpiece 200 based on the thickness of the workpiece 200 in the area slightly inside the outer edge of the workpiece 200. Here, the amount of grinding in the area slightly inside the outer edge of the workpiece 200 indicates the thickness of the workpiece 200 (film 202 and base material 201) ground in the area slightly inside the outer edge of the workpiece 200.

The control unit 60 calculates the base material exposure ratio on the side of the workpiece 200 where the grinding process is performed based on the thickness of the film 202 on the workpiece 200 before grinding, the amount of grinding in the area slightly inside the outer edge of the workpiece 200 calculated as described above, and the inclination angle of the grinding surface 25 of the grinding wheel 21 relative to the holding surface 11 of the holding table 10 obtained as described above. Here, the base material exposure ratio indicates the ratio of the area of the exposed base material 201 to the total area of the side of the workpiece 200 where the grinding process is performed.

Figure 6 is a diagram showing an example of processing sequence data 65 stored by the control unit 60 of the grinding device 1 of Figure 1. The storage device of the control unit 60 stores, as processing sequence data 65 shown in Figure 6, information used in the arithmetic processing executed by the arithmetic processing device of the control unit 60 when performing the workpiece grinding method of embodiment 1 on the workpiece 200. The processing sequence data 65 is stored in advance in the storage device of the control unit 60 based on information input by an operator to an input unit (not shown) before the grinding device 1 performs the workpiece grinding method.

As shown in FIG. 6, the storage device of the control unit 60 stores the processing order data 65, which corresponds one-to-one to the processing order of each process when the grinding device 1 performs the grinding method for the workpiece, the tilt angle for each process, the grinding time for each process, the estimated grinding amount for each process, and the estimated base material exposure ratio for each process.

In the first embodiment, the processing sequence data 65 is configured such that in the first processing step, the tilt angle 1 is set to a non-zero value to bring the holding surface 11 of the holding table 10 and the grinding surface 25 of the grinding wheel 21 into a non-parallel state, and in the second processing step, the tilt angle 2 is set to 0 to bring the holding surface 11 of the holding table 10 and the grinding surface 25 of the grinding wheel 21 into a parallel state.

In the first embodiment, the processing sequence data 65 is set as grinding time 1 for the first processing step, which is based on the operator's prior investigation through experiments, etc., and the grinding time until the grinding amount or base material exposure ratio reaches a predetermined amount, for example, grinding amount 1 or base material exposure ratio 1. Similarly, the processing sequence data 65 is set as grinding time 2 for the second processing step, which is based on the operator's prior investigation through experiments, and the grinding time until the grinding amount or base material exposure ratio reaches a predetermined amount, for example, grinding amount 2 or base material exposure ratio 2. Here, in the first embodiment, the base material exposure ratio 1 is set to a predetermined ratio at which at least a part of the base material 201 is exposed, for example, less than 100%, such as 30% or 50%, and the base material exposure ratio 2 is set to 100%, which corresponds to the time when the base material 201 is completely exposed and the film 202 is completely removed. Also, in embodiment 1, grinding amount 1 is set to the grinding amount when the base material exposure ratio becomes the set base material exposure ratio 1, and grinding amount 2 is set to be equal to or greater than the grinding amount when the base material exposure ratio becomes the set base material exposure ratio 2.

In the first embodiment, the processing sequence data 65 is set so that the processing sequence is divided into only two stages, the first process and the second process, but the present invention is not limited to this. For example, the processing may be set to be divided into three or more stages, and the inclination angle of the holding surface 11 of the holding table 10 relative to the grinding surface 25 of the grinding wheel 21 may be gradually decreased as the grinding process proceeds and the grinding amount and the exposed ratio of the base material increase, or the grinding feed speed for bringing the grinding wheel 22 closer to the holding table 10 may be increased.

The control unit 60 thus refers to processing sequence data 65 in which each process when carrying out the grinding method for the workpiece is preset, and sequentially executes the first and second processes in the processing sequence, thereby realizing the present invention's process of activating the grinding state change unit 40 to make the holding surface 11 and the grinding surface 25 of the grinding wheel 21 non-parallel, starting grinding with the grinding surface 25 in contact with a part of the film 202, grinding the workpiece 200 while increasing the area of the workpiece 200 in contact with the grinding surface 25 in accordance with the grinding feed of the grinding wheel 22, and controlling the grinding feed unit 30 to grind while controlling the grinding state change unit 40 so as to gradually change the holding surface 11 and the grinding surface 25 of the grinding wheel 21 from the non-parallel state to a parallel state when a predetermined amount of the film 202 has been ground. Here, in embodiment 1, a predetermined amount of film 202 being ground away corresponds to the amount of grinding reaching a predetermined amount, grinding amount 1, or the base material exposure ratio reaching a base material exposure ratio 1, which is a predetermined ratio at which at least a portion of base material 201 is exposed.

As shown in FIG. 1, the grinding device 1 further includes cassettes 91 and 92, an alignment unit 93, a carry-in unit 94, an unloading unit 95, a cleaning unit 96, and a carry-in/out unit 98. As shown in FIG. 1, the cassettes 91 and 92 are containers for storing multiple workpieces 200. The alignment unit 93 is a table on which the workpiece 200 removed from the cassette 91 is temporarily placed and on which the center of the workpiece 200 is aligned.

The carry-in unit 94 has a suction pad, and adsorbs and holds the workpiece 200 before grinding that has been aligned by the alignment unit 93, and carries it onto the holding table 10 located at the carry-in/carry-out position. The carry-out unit 95 adsorbs and holds the workpiece 200 after grinding that is held on the holding table 10 located at the carry-in/carry-out position, and carries it out to the cleaning unit 96. The cleaning unit 96 cleans the workpiece 200 after grinding, and removes contamination such as grinding debris adhering to the ground surface.

The loading/unloading unit 98 is, for example, a robot pick equipped with a circular hand, and transports the workpiece 200 by suctioning and holding the workpiece 200 with the circular hand. Specifically, the loading/unloading unit 98 transports the workpiece 200 before grinding from the cassette 91 to the alignment unit 93, and transports the workpiece 200 after grinding from the cleaning unit 96 to the cassette 92.

Next, this specification describes an example of a grinding method for a workpiece according to embodiment 1, which is an example of the operation of the grinding device 1 according to embodiment 1, with reference to the drawings. FIG. 7 is a flowchart showing an example of a processing procedure of the grinding method for a workpiece according to embodiment 1. As shown in FIG. 7, the grinding method for a workpiece according to embodiment 1 includes a holding step 1001, a first grinding step 1002, and a second grinding step 1003.

In the holding step 1001, the holding table 10 holds the workpiece 200 on the holding surface 11 so that the surface of the workpiece 200 on which the film 202 is formed is exposed. In the holding step 1001, the holding table 10 holds the adhesive surface side of the adhesive tape 205 attached to the side of the workpiece 200 opposite the surface on which the film 202 is formed, on the holding surface 11, with the surface on which the film 202 is formed of the workpiece 200 facing upward relative to the holding table 10, which is the side on which the grinding unit 20 is provided.

Figure 8 is a cross-sectional view explaining the first grinding step 1002 in Figure 7. The first grinding step 1002 is performed after the holding step 1001, and as shown in Figure 8, the holding surface 11 and the grinding surface 25 of the grinding wheel 21 are made non-parallel so as to be separated by a predetermined distance, grinding is started with the grinding surface 25 in contact with a part of the film 202, and the workpiece 200 is ground while the area of the workpiece 200 in contact with the grinding surface 25 is gradually increased according to the grinding feed of the grinding wheel 22.

In the first grinding step 1002, first, the control unit 60 controls the grinding state change unit 40 while separating the holding surface 11 of the holding table 10 and the grinding surface 25 of the grinding wheel 21 by a predetermined distance or more, thereby controlling the inclination angle of the grinding surface 25 of the grinding wheel 21 relative to the holding surface 11 of the holding table 10, thereby making the holding surface 11 of the holding table 10 and the grinding surface 25 of the grinding wheel 21 non-parallel. In the first grinding step 1002, in the first embodiment, the control unit 60 forms a state in which the grinding surface 25 of the grinding wheel 21 is inclined by an angle θ1 in a direction in which the inside of the holding surface 11 of the holding table 10 is closer to the holding surface 11 of the holding table 10 than the outside of the holding surface 11 of the holding table 10, as shown in FIG. 2.

In the first grinding step 1002, the control unit 60 then rotates the holding table 10 and the grinding wheel 22 of the grinding unit 20. In the first grinding step 1002, the control unit 60 then controls the grinding feed unit 30 while rotating the holding table 10 and the grinding wheel 22, as shown in FIG. 8, to bring the grinding unit 20 closer to the holding table 10, bring the grinding surface 25 into contact with the outer peripheral portion (outer edge) of the film 202, and start grinding the workpiece 200 from the surface side on which the film 202 is formed.

In the first grinding step 1002, in the first embodiment, the grinding surface 25 of the grinding wheel 21 is inclined relative to the holding surface 11 of the holding table 10 before it is brought into contact with the holding surface 11, but the present invention is not limited to this, and the grinding surface 25 of the grinding wheel 21 may be inclined after it is brought into contact with the holding surface 11 of the holding table 10.

In the first grinding step 1002, the control unit 60 further controls the grinding feed unit 30 to press the grinding unit 20 against the holding table 10 in the vertical direction, thereby feeding the grinding wheel 22 against the workpiece 200 on the holding table 10, and grinding the workpiece 200 while gradually increasing the area of the workpiece 200 in contact with the grinding surface 25 according to the grinding feed of the grinding wheel 22. In the first grinding step 1002, in the first embodiment, as the workpiece 200 is ground, as shown in FIG. 4, the workpiece 200 is ground from the outer periphery, the film 202 is removed from the outer periphery to expose the base material 201, and the area where the film 202 is removed and the base material 201 is exposed expands from the outer periphery toward the center.

In the first grinding step 1002, the holding surface 11 of the holding table 10 and the grinding surface 25 of the grinding wheel 21 are ground in a non-parallel state, so that the contact area between the grinding wheel 21 and the film 202 of the workpiece 200 during grinding can be suppressed to be smaller than when grinding in a parallel state. Therefore, in the first grinding step 1002, the risk of the highly viscous film 202 adhering to the grinding wheel 21 during grinding can be reduced. In addition, in the first grinding step 1002, when at least a part of the base material 201 is exposed, the grinding wheel 21 and the base material 201 come into contact during grinding, so that the dressing effect of the base material 201 on the grinding wheel 21 caused by this allows the film 202 adhering to the grinding wheel 21 to be suitably removed, thereby further reducing the grinding resistance applied to the grinding wheel 21 and enabling stable grinding processing to be performed. This dressing effect is particularly pronounced when the base material 201 is silicon.

In the first grinding step 1002, in the first embodiment, the control unit 60 refers to the processing sequence data 65 and continues the grinding process for the grinding time 1 associated with the first process in the processing sequence, thereby causing the grinding amount and base material exposure ratio of the workpiece 200 to approximately reach the grinding amount 1 and base material exposure ratio 1 associated with the first process in the processing sequence. As a result, in the first grinding step 1002, the control unit 60 realizes a state in which a predetermined amount of the film 202 is ground in the first grinding step 1002.

Figure 9 is a cross-sectional view explaining the second grinding step 1003 in Figure 7. As shown in Figure 9, the second grinding step 1003 is performed after the first grinding step 1002. When a predetermined amount of the film 202 is ground in the first grinding step 1002, the workpiece 200 is ground by gradually changing the holding surface 11 and the grinding surface 25 of the grinding wheel 21 from a non-parallel state to a parallel state while being fed for grinding.

In the second grinding step 1003, the control unit 60 controls the grinding state change unit 40 to control the inclination angle of the grinding surface 25 of the grinding wheel 21 relative to the holding surface 11 of the holding table 10, gradually changing the holding surface 11 of the holding table 10 and the grinding surface 25 of the grinding wheel 21 from a non-parallel state to a parallel state. In the second grinding step 1003, the control unit 60 controls the grinding feed unit 30 to grind and feed the grinding wheel 22, following the first grinding step 1002.

In the second grinding step 1003, at least a part of the base material 201 is exposed at the start of the process. In the second grinding step 1003, in the first embodiment, the base material exposure ratio reaches a predetermined amount at the start of the process. Therefore, in the second grinding step 1003, the contact area between the grinding wheel 21 and the film 202 of the workpiece 200 during grinding can be suppressed to a small area compared to the conventional method of grinding in a parallel state. In addition, in the second grinding step 1003, the grinding wheel 21 and the base material 201 come into contact during grinding, and a dressing effect of the base material 201 against the grinding wheel 21 caused by this can be obtained. Therefore, in the second grinding step 1003, even if a certain amount of the film 202 remains, the same grinding resistance suppression effect as in the first grinding step 1002 can be obtained, and a stable grinding process can be performed.

After this second grinding step 1003, the ground workpiece 200 has the film 202 completely removed, and the surface of the base material 201 that has been ground by the grinding wheel 21 (the surface to be ground) is formed parallel to the holding surface 11 of the holding table 10.

The grinding device 1 and the grinding method of the workpiece according to the first embodiment having the above-mentioned configuration make the holding surface 11 and the grinding surface 25 of the grinding wheel 21 in a non-parallel state, start grinding in a state where the grinding surface 25 is in contact with a part (peripheral part) of the film 202, grind the workpiece 200 while increasing the area of the workpiece 200 in contact with the grinding surface 25 from the peripheral part toward the center, and when a predetermined amount of the film 202 is ground, the holding surface 11 and the grinding surface 25 of the grinding wheel 21 are gradually changed from the non-parallel state to a parallel state, and the grinding feed is performed, thereby grinding the workpiece 200 from the film 202 side. Therefore, the grinding device 1 and the grinding method of the workpiece according to the first embodiment can reduce the risk of the highly viscous film 202 adhering to the grinding wheel 21, so that even if a highly viscous film 202 is formed, it is possible to stably grind from the film 202 side.

[Embodiment 2]
A grinding device 1 and a grinding method for a workpiece according to a second embodiment of the present invention will be described. Fig. 10 is a cross-sectional view illustrating a first grinding step 1002 of the grinding method for a workpiece according to the second embodiment. In Fig. 10, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

The grinding device 1 and the method for grinding a workpiece according to the second embodiment are the same as those according to the first embodiment, except that in the first grinding step 1002, the inclination direction of the grinding surface 25 of the grinding wheel 21 relative to the holding surface 11 of the holding table 10 is reversed, as shown in FIG. 10.

Specifically, in the first grinding step 1002 according to the second embodiment, the control unit 60 forms a state in which the grinding surface 25 of the grinding wheel 21 is inclined by an angle θ2 with respect to the holding surface 11 of the holding table 10, as shown in FIG. 3, in a direction in which the area vertically facing the inside of the holding surface 11 of the holding table 10 is closer to the holding surface 11 of the holding table 10 than the area vertically facing the outside of the holding surface 11. In the first grinding step 1002 according to the second embodiment, the control unit 60 controls the grinding feed unit 30 while rotating the holding table 10 and rotating the grinding wheel 22, as shown in FIG. 10, to bring the grinding unit 20 closer to the holding table 10, bring the grinding surface 25 into contact with the center part of the film 202, and start grinding the workpiece 200 from the surface side on which the film 202 is formed.

In the first grinding step 1002 according to the second embodiment, as the workpiece 200 is ground, as shown in FIG. 5, the workpiece 200 is ground from the center, the film 202 is removed from the center to expose the base material 201, and the area where the film 202 is removed to expose the base material 201 expands from the center toward the outer periphery.

The grinding device 1 and the grinding method for the workpiece according to the second embodiment having the above-mentioned configuration are the same as those of the first embodiment except that in the first grinding step 1002, the inclination direction of the grinding surface 25 of the grinding wheel 21 relative to the holding surface 11 of the holding table 10 is reversed. Therefore, the grinding device 1 and the grinding method for the workpiece according to the second embodiment have the same effect as those of the first embodiment.

[Embodiment 3]
A grinding device 1 and a grinding method for a workpiece according to a third embodiment of the present invention will be described. Fig. 11 is a flowchart showing an example of a processing procedure of the grinding method for a workpiece according to the third embodiment. In Fig. 11, the same parts as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

The grinding device 1 and the grinding method of the workpiece according to the third embodiment further includes a grinding amount measuring step 1004 and a grinding amount determining step 1005 as shown in FIG. 11 in the first and second embodiments. The grinding device 1 and the grinding method of the workpiece according to the third embodiment controls the grinding time in the first grinding step 1002 by performing a grinding amount measuring step 1004 and a grinding amount determining step 1005, instead of the control unit 60 referring to the processing order data 65 in the first grinding step 1002 and continuing the grinding process for the grinding time 1 associated with the first process in the processing order in the first grinding step 1002 in the first and second embodiments.

The grinding amount measurement step 1004 is a step for measuring the amount of grinding in an area slightly inside the outer edge of the workpiece 200 during grinding in the first grinding step 1002.

In the grinding amount measurement step 1004, the control unit 60 first controls the grinding amount detection unit 50 to detect the thickness of the workpiece 200 in a region slightly inside the outer edge of the workpiece 200, and acquires information on the thickness. In the grinding amount measurement step 1004, the control unit 60 then calculates the grinding amount in the region slightly inside the outer edge of the workpiece 200 based on the acquired thickness information.

Grinding amount determination step 1005 is a step for determining whether the grinding amount in the area slightly inside the outer edge of the workpiece 200 measured in grinding amount measurement step 1004 is equal to or greater than a predetermined amount.

In the grinding amount determination step 1005, if the control unit 60 determines that the grinding amount measured in the grinding amount measurement step 1004 is equal to or greater than the predetermined amount (Yes in the grinding amount determination step 1005), it determines that a sufficient area percentage of the film 202 has been removed in the first grinding step 1002 and that a sufficient area percentage of the base material 201 has been exposed, and ends the first grinding step 1002, and advances the processing of the grinding method for the workpiece according to the third embodiment to the second grinding step 1003. In the grinding amount determination step 1005, the control unit 60, for example, refers to the processing order data 65 and sets the grinding amount 1 associated with the first processing in the processing order to the predetermined amount of grinding amount described above.

In the grinding amount determination step 1005, if the control unit 60 determines that the grinding amount measured in the grinding amount measurement step 1004 is less than the predetermined amount (No in the grinding amount determination step 1005), it determines that a sufficient area ratio of the film 202 has not been removed in the first grinding step 1002 and that a sufficient area ratio of the base material 201 has not been exposed, and continues the first grinding step 1002, and returns the processing of the grinding method of the workpiece according to the third embodiment to the grinding amount measurement step 1004 again. In the grinding method of the workpiece according to the third embodiment, the control unit 60 continues the first grinding step 1002 and repeats the grinding amount measurement step 1004 and the grinding amount determination step 1005 until it determines that the grinding amount is equal to or greater than the predetermined amount in the grinding amount determination step 1005.

In the method for grinding a workpiece according to the third embodiment, the control unit 60 continues the first grinding step 1002 until the grinding amount reaches a predetermined amount, and repeats the grinding amount measurement step 1004 and the grinding amount determination step 1005, thereby realizing a state in which the film 202 is ground off by a predetermined amount in the first grinding step 1002.

In the grinding method of the workpiece according to the third embodiment, the grinding amount is measured in the grinding amount measurement step 1004, and it is determined whether the grinding amount is equal to or greater than a predetermined amount in the grinding amount determination step 1005. However, the present invention is not limited to this, and the base material exposure ratio may be detected instead of the grinding amount, and instead of determining whether the grinding amount is equal to or greater than a predetermined amount, it may be determined whether the base material exposure ratio is equal to or greater than a predetermined amount. When determining whether the base material exposure ratio is equal to or greater than a predetermined amount, the control unit 60, for example, refers to the processing sequence data 65 and sets the base material exposure ratio 1 associated with the first processing in the processing sequence to the above-mentioned predetermined amount of the base material exposure ratio.

In addition, in the grinding method of the workpiece according to the third embodiment, the grinding feed amount of the grinding feed unit 30 may be detected instead of the grinding amount, and instead of determining whether the grinding amount is equal to or greater than the predetermined amount, it may be determined whether the grinding feed amount is equal to or greater than the predetermined amount. When determining whether the grinding feed amount is equal to or greater than the predetermined amount, the control unit 60 sets the grinding feed amount calculated based on the grinding amount 1 associated with the first process in the process order obtained by referring to the process order data 65 and the inclination angle of the grinding surface 25 of the grinding wheel 21 relative to the holding surface 11 of the holding table 10 to the above-mentioned predetermined amount. In addition, in the grinding method of the workpiece according to the third embodiment, a correction value equivalent to the wear amount of the grinding wheel 21 may be added to the above-mentioned predetermined amount in consideration of the wear of the grinding wheel 21.

The grinding device 1 and the grinding method of the workpiece according to the third embodiment having the above configuration detect the amount of grinding and the ratio of exposed base material, and determine whether or not these are equal to or greater than a predetermined amount, thereby switching from the first grinding step 1002 to the second grinding step 1003. Therefore, the grinding device 1 and the grinding method of the workpiece according to the third embodiment have the same effect as the first and second embodiments. In addition to the first and second embodiments, the grinding device 1 and the grinding method of the workpiece according to the third embodiment can more reliably switch to the second grinding step 1003 when the amount of grinding or the ratio of exposed base material in the first grinding step 1002 becomes equal to or greater than a predetermined amount, and therefore have the effect of being able to grind from the film 202 side more stably.

[Embodiment 4]
A grinding device 1-2 and a grinding method for a workpiece according to a fourth embodiment of the present invention will be described. FIG. 12 is a perspective view showing a configuration example of a grinding device 1-2 according to the fourth embodiment. FIG. 13 is a flowchart showing a first example of a processing procedure of the grinding method for a workpiece according to the fourth embodiment. FIG. 14 is a flowchart showing a second example of a processing procedure of the grinding method for a workpiece according to the fourth embodiment. FIG. 15 is a flowchart showing a third example of a processing procedure of the grinding method for a workpiece according to the fourth embodiment. FIG. 16 is a flowchart showing a fourth example of a processing procedure of the grinding method for a workpiece according to the fourth embodiment. In FIGS. 13 to 16, the same reference numerals are assigned to the same parts as those in the first, second and third embodiments, and the description thereof will be omitted.

As shown in FIG. 12, the grinding device 1-2 according to the fourth embodiment includes a holding table 10, a turntable 15, grinding feed units 30-1 and 30-2, a grinding state change unit 40, a grinding amount detection unit 50, a control unit 60, a rough grinding unit 70, and a finish grinding unit 80. The rough grinding unit 70 and the finish grinding unit 80 according to the fourth embodiment are both grinding units according to the present invention.

As shown in FIG. 12, three holding tables 10 are installed on the turntable 15. These three holding tables 10 are arranged on the turntable 15 so as to be rotatable in a generally horizontal plane (XY plane) independently of the turntable 15. As shown in FIG. 12, the turntable 15 is a disk-shaped table that is arranged so as to be rotatable in a horizontal plane and is rotated at a predetermined timing. The three holding tables 10 are arranged on the turntable 15 at equal intervals, for example, at a phase angle of 120°. These three holding tables 10 are moved sequentially to the loading/unloading position 101, the rough grinding position 102, the finish grinding position 103, and the loading/unloading position 101 by the rotation of the turntable 15.

As shown in FIG. 12, the rough grinding unit 70 includes a grinding wheel 72 having grinding stones 71 arranged in an annular shape, a spindle 73, and a servo motor 74. The grinding stone 71 has a grinding surface 75 on the lower side. The rough grinding unit 70 is the same as the grinding unit 20 in the first to third embodiments, except that the rough grinding unit 70 processes the workpiece 200 on the holding table 10 positioned at the rough grinding position 102. In addition, the grinding stone 71, the grinding wheel 72, the spindle 73, the servo motor 74, and the grinding surface 75 are the same as the grinding stone 21, the grinding wheel 22, the spindle 23, the servo motor 24, and the grinding surface 25 in the first to third embodiments.

As shown in FIG. 12, the finish grinding unit 80 includes a grinding wheel 82 having grinding stones 81 arranged in a ring shape, a spindle 83, and a servo motor 84. The grinding stone 81 has a grinding surface 85 on the lower side. The finish grinding unit 80 is the same as the grinding unit 20 in the first to third embodiments except for processing the workpiece 200 on the holding table 10 positioned at the finish grinding position 103 and the abrasive grain size and granularity of the grinding stone 81. The grinding wheel 82, spindle 83, servo motor 84, and grinding surface 85 are the same as the grinding wheel 22, spindle 23, servo motor 24, and grinding surface 25 in the first to third embodiments. In the fourth embodiment, the grinding stone 81 has a relatively small abrasive grain size, for example, a grain size of #1400 (1400th number) or more, so-called base material 201 is for finishing polishing the workpiece 200 made of silicon. The grinding wheel 81 is the same as the grinding wheel 21 in embodiments 1 to 3, except for the abrasive grain size and particle size.

The grinding feed unit 30-1 is attached to the rough grinding unit 70, and feeds the rough grinding unit 70 for grinding in a vertical direction (Z-axis direction) that is generally perpendicular to the holding surface 11 of the holding table 10 positioned at the rough grinding position 102. The grinding feed unit 30-2 is attached to the finish grinding unit 80, and feeds the finish grinding unit 80 for grinding in a vertical direction (Z-axis direction) that is generally perpendicular to the holding surface 11 of the holding table 10 positioned at the finish grinding position 103. Other than the above, the grinding feed units 30-1 and 30-2 are the same as the grinding feed unit 30 in the first to third embodiments.

When both the rotation axis 19 of the holding surface 11 of the holding table 10 positioned at the rough grinding position 102 and the rotation axis of the grinding surface 75 of the grinding wheel 71 are held parallel to the XY plane, they are positioned offset from each other in a direction within the XY plane. When both the rotation axis 19 of the holding surface 11 of the holding table 10 positioned at the finish grinding position 103 and the rotation axis of the grinding surface 85 of the grinding wheel 81 are held parallel to the XY plane, they are positioned offset from each other in a direction within the XY plane.

The rough grinding unit 70 rotates the grinding wheel 72 and presses the workpiece 200 held on the holding table 10 positioned at the rough grinding position 102 along the Z-axis direction parallel to the vertical direction with the grinding feed unit 30-1 against the surface on which the film 202 is formed of the workpiece 200. The finish grinding unit 80 rotates the grinding wheel 82 and presses the workpiece 200 held on the holding table 10 positioned at the finish grinding position 103 along the Z-axis direction parallel to the vertical direction with the grinding feed unit 30-2, thereby finish grinding the workpiece 200 from the surface on which the film 202 is formed.

In the fourth embodiment, the grinding surface tilting unit 40-1 of the grinding state change unit 40 is provided in the rough grinding unit 70, and tilts the grinding surface 75 of the grinding wheel 71 by rotating the rough grinding unit 70 around the X-axis. In the fourth embodiment, the holding surface tilting unit 40-2 of the grinding state change unit 40 is provided in each of the holding tables 10, and tilts the holding surface 11 of the holding table 10 by independently rotating each holding table 10 around the X-axis.

In the fourth embodiment, the grinding amount detection unit 50 is provided near the outer periphery of the holding surface 11 of the holding table 10 positioned at the rough grinding position 102. The grinding amount detection unit 50 is the same as the grinding amount detection unit 50 in the first to third embodiments, except for the position where it is provided.

Next, this specification describes an example of a grinding method for a workpiece according to embodiment 4, which is an example of the operation of the grinding device 1-2 according to embodiment 4, with reference to the drawings. As shown in Figs. 13 to 16, the grinding method for a workpiece according to embodiment 4 includes a rough grinding step 2001 and a finish grinding step 2002.

The holding step 1001 in embodiment 4 is a step in which the holding table 10 positioned at the loading/unloading position 101 holds the workpiece 200 loaded onto the holding table 10 on the holding surface 11 so that the surface of the workpiece 200 on which the film 202 is formed is exposed.

In the rough grinding step 2001, the control unit 60 rotates the turntable 15 to move the holding table 10, which holds the workpiece 200 in the holding step 1001, from the loading/unloading position 101 to the rough grinding position 102, and then the rough grinding unit 70 roughly grinds the workpiece 200 held on the holding table 10 positioned at the rough grinding position 102 from the side on which the film 202 is formed.

In the finish grinding step 2002, the control unit 60 rotates the turntable 15 to move the holding table 10 holding the workpiece 200 roughly ground in the rough grinding step 2001 from the rough grinding position 102 to the finish grinding position 103, and then the finish grinding unit 80 finish-grinds the workpiece 200 held on the holding table 10 positioned at the finish grinding position 103 from the side on which the film 202 is formed.

As shown in FIG. 13, the first example of the grinding method for the workpiece according to the fourth embodiment involves performing a process similar to that performed by the grinding unit 20 in the first grinding step 1002 according to the first and second embodiments using the rough grinding unit 70 in the rough grinding step 2001 to completely remove the film 202 from the workpiece 200, and performing a process similar to that performed by the grinding unit 20 in the second grinding step 1003 according to the first and second embodiments using the finish grinding unit 80 in the finish grinding step 2002.

As shown in FIG. 14, the second example of the grinding method for the workpiece according to the fourth embodiment involves performing processes similar to those performed by the grinding unit 20 in the first grinding step 1002, the grinding amount measurement step 1004, and the grinding amount determination step 1005 according to the third embodiment using the rough grinding unit 70 in the rough grinding step 2001 to completely remove the film 202 from the workpiece 200, and performing processes similar to those performed by the grinding unit 20 in the second grinding step 1003 according to the third embodiment using the finish grinding unit 80 in the finish grinding step 2002.

As shown in FIG. 15, the third example of the grinding method for the workpiece according to the fourth embodiment involves performing a process similar to that performed by the grinding unit 20 in the first grinding step 1002 and the second grinding step 1003 according to the first and second embodiments by the rough grinding unit 70 in the rough grinding step 2001 to completely remove the film 202 of the workpiece 200, and additionally performing a finish grinding step 2002 by the finish grinding unit 80.

As shown in FIG. 16, in a fourth example of the grinding method for the workpiece according to the fourth embodiment, in a rough grinding step 2001, the rough grinding unit 70 performs processes similar to those performed by the grinding unit 20 in the first grinding step 1002, the grinding amount measurement step 1004, the grinding amount determination step 1005, and the second grinding step 1003 according to the third embodiment, to completely remove the film 202 of the workpiece 200, and additionally, a finish grinding step 2002 is performed by the finish grinding unit 80.

The grinding device 1-2 and the grinding method of the workpiece according to the fourth embodiment having the above configuration completely remove the film 202 of the workpiece 200 in the rough grinding step 2001, and then perform the finish grinding step 2002 on the workpiece 200 with the base material 201 exposed on the entire surface. Therefore, in addition to the features of the first and second embodiments, the grinding device 1-2 and the grinding method of the workpiece according to the fourth embodiment further have the effect of reliably preventing the highly viscous film 202 from adhering to the grinding wheel 81 for finish grinding, which has a relatively small abrasive grain size and a large grain number, and therefore is prone to adhering to the highly viscous film 202, thereby enabling the rough grinding and the finish grinding to be performed stably from the film 202 side. In addition, the grinding device 1-2 and the grinding method of the workpiece according to the fourth embodiment have the effect of quickly performing the finish grinding, since the finish grinding can be performed only in a parallel state.

The present invention is not limited to the above embodiment. In other words, the present invention can be implemented in various modifications without departing from the gist of the invention.

1, 1-2 Grinding device 10 Holding table 11 Holding surface 20 Grinding unit 21 Grinding stone 22 Grinding wheel 24 Servo motor (driving source)
25 Grinding surface 30 Grinding feed unit 40 Grinding state change unit 50 Grinding amount detection unit 60 Control unit 70 Rough grinding unit (grinding unit)
80 Finish grinding unit (grinding unit)
200 Workpiece 201 Base material 202 Film

Claims (2)

1. A grinding apparatus comprising:
The grinding device comprises:
a holding table having a holding surface for holding a workpiece having a film formed on one surface of a substrate such that the surface on which the film is formed is exposed;
a grinding unit including a grinding wheel having a grinding stone for grinding the workpiece held on the holding surface from the surface on which the film is formed, and a drive source for rotating the grinding wheel;
a grinding feed unit for feeding the grinding unit in a direction perpendicular to the holding table;
a grinding state changing unit for changing the state between a parallel state and a non-parallel state between the holding surface and the grinding surface of the grinding wheel;
A control unit for controlling the grinding state changing unit;
Equipped with
The control unit
When the holding table is rotated and the grinding wheel is rotated while being fed for grinding to grind the workpiece held on the holding surface,
activating the grinding state changing unit to make the holding surface and the grinding surface of the grinding wheel non-parallel to start grinding in a state where the grinding surface is in contact with a part of the film, and grinding the workpiece while increasing the area of the workpiece in contact with the grinding surface according to the grinding feed of the grinding wheel;
The grinding device detects a grinding amount, which is the thickness by which the workpiece has been ground, or a base material exposure ratio, which is the ratio of the area of the exposed base material of the workpiece to the total area of the surface side of the workpiece being ground, when the film is ground off by a predetermined amount, and determines that the detected grinding amount or base material exposure ratio is equal to or greater than a predetermined amount, switches to control the grinding feed unit so as to grind while controlling the grinding state change unit so as to gradually change the holding surface and the grinding surface of the grinding wheel from a non-parallel state to a parallel state. A holding table having a holding surface for holding a workpiece;
a grinding unit including a grinding wheel having a grinding stone for grinding the workpiece held on the holding surface and a drive source for rotating the grinding wheel;
a grinding feed unit for feeding the grinding unit in a direction perpendicular to the holding table;
a grinding state changing unit for changing the state between a parallel state and a non-parallel state between the holding surface and the grinding surface of the grinding wheel;
A control unit for controlling the grinding state changing unit;
By a grinding device including
a grinding method for a workpiece, the grinding wheel being rotated while being fed for grinding to grind the workpiece held on the holding surface, the method comprising:
a holding step of holding the workpiece on the holding surface such that a film is formed on one surface of the substrate of the workpiece and the surface on which the film is formed is exposed;
a first grinding step in which the holding surface and the grinding surface of the grinding wheel are in a non-parallel state with a predetermined distance between them, grinding is started in a state in which the grinding surface is in contact with a part of the film, and the workpiece is ground while the area of the workpiece in contact with the grinding surface is gradually increased according to the grinding feed of the grinding wheel;
a second grinding step in which, when a predetermined amount of the film is ground away in the first grinding step, the holding surface and the grinding surface of the grinding wheel are gradually changed from a non-parallel state to a parallel state while being fed for grinding to grind the workpiece;
Equipped with
The control unit detects a grinding amount, which is the thickness of the workpiece ground, or a base material exposure ratio, which is the ratio of the area of the exposed base material of the workpiece to the total area of the surface side of the workpiece being ground, and switches from the first grinding step to the second grinding step when it determines that the detected grinding amount or base material exposure ratio is equal to or greater than a predetermined amount .

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