Dressing board and dressing method

Abstract

To shorten the dressing time of a grinding wheel.SOLUTION: A dressing board 120 includes a first dressing grinding wheel 121 for shaping and a second dressing grinding wheel 122 for dressing, arranged under the first dressing grinding wheel 121. Thus, by lowering a rough grinding wheel 306 while grinding the dressing board 120 with the rotating rough grinding wheel 306, the rough grinding wheel 306 is allowed to cut into the first dressing grinding wheel 121 for shaping and the second dressing grinding wheel 122 for dressing, in this order. Therefore, shaping and dressing of the rough grinding wheel 306 can be easily performed without moving the rough grinding wheel 306 in the horizontal direction. Thus, the dressing time of the rough grinding wheel 306 can be shortened.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a dressing board and a dressing method. [Background technology]

[0002] As disclosed in Patent Documents 1 and 2, in a dressing board for dressing a grinding wheel, a dressing wheel for shaping formed from abrasive grains larger than those of the grinding wheel, and a dressing wheel for sharpening formed from abrasive grains smaller than those of the grinding wheel are arranged on a base. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-142906 A [Patent Document 2] JP 2023-084189 A Summary of the Invention [Problem to be solved by the invention]

[0004] In dressing a grinding wheel, the above-mentioned dressing board is held on the chuck table, the chuck table is rotated, the grinding wheel is shaped, and then the grinding wheel is brought into contact with only the dressing wheel for sharpening, and sharpening is performed. Therefore, it takes time to move the chuck table horizontally.

[0005] SUMMARY OF THE PRESENTLY PREFERRED EMBODIMENTS It is therefore an object of the present invention to reduce the time required for dressing a grinding wheel, which involves shaping and sharpening the grinding wheel. [Means for solving the problem]

[0006] The dressing board of the present invention (the present dressing board) is a dressing board for dressing a grinding wheel that grinds a workpiece, and has a first dressing wheel for shaping which includes first abrasive grains fixed with a first bond material, and a second dressing wheel for sharpening which is positioned below the first dressing wheel and includes second abrasive grains fixed with a second bond material.

[0007] In the dressing board, the first abrasive grains may be larger than the second abrasive grains.

[0008] In the present dressing board, the first dressing grindstone may have a higher concentration than the second dressing grindstone.

[0009] In the present dressing board, the first dressing grindstone may be harder than the second dressing grindstone.

[0010] In this case, the first abrasive grains may be harder than the second abrasive grains, and / or the first bond material may be harder than the second bond material.

[0011] The dressing method of the present invention (the present dressing method) is a dressing method for dressing a ring-shaped grinding wheel for grinding a workpiece using the present dressing board, and includes a holding step of holding the dressing board by a table so that the first dressing wheel faces upward, a first dressing step of lowering the grinding wheel to cut into the first dressing wheel on the dressing board, and a second dressing step of lowering the grinding wheel following the first dressing step to cut into the second dressing wheel below the first dressing wheel on the dressing board. Effect of the Invention

[0012] This dressing board has a first dressing grindstone for shaping and a second dressing grindstone for sharpening arranged below the first dressing grindstone. Therefore, by lowering the grinding wheel while grinding the dressing board with a rotating grinding wheel, the grinding wheel can be cut into the first dressing grindstone for shaping and the second dressing grindstone for sharpening in this order. Therefore, in this embodiment, the grinding wheel can be easily shaped and sharpened without moving the grinding wheel in the horizontal direction. Therefore, it is possible to shorten the dressing time of the grinding wheel. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a perspective view showing a configuration of a grinding device. [Diagram 2] FIG. [Diagram 3] An oblique view showing the configuration of a dressing board. [Figure 4] FIG. 4 is a side cross-sectional view showing a first dressing step. [Diagram 5] FIG. 4 is a side cross-sectional view showing a first dressing step. [Figure 6] FIG. 4 is a side cross-sectional view showing a second dressing step. [Figure 7] An oblique view showing the dressing board after the second dressing step. [Figure 8] FIG. [Figure 9] FIG. 4 is a side cross-sectional view showing a first dressing step and a second dressing step. [Figure 10] 3A to 3C are diagrams showing examples of preferred combinations of first abrasive grains, a first bond material, a second abrasive grains, and a second bond material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The grinding apparatus 1 shown in FIG. 1 grinds a wafer 100 held on a chuck table 5 by means of a rough grinding mechanism 30 and a finish grinding mechanism 31 . In particular, the grinding apparatus 1 is configured to form a circular recess and an annular protrusion along the outer periphery of the circular recess on the wafer 100. That is, the grinding apparatus 1 is configured to perform a so-called TAIKO grinding process on the wafer 100.

[0015] A wafer 100 shown in Fig. 1 is an example of a workpiece, for example a circular semiconductor wafer. A device (not shown) is formed on a front surface 101 of the wafer 100. The front surface 101 of the wafer 100 faces downward in Fig. 1 and is protected by a protective tape 103 attached thereto. A back surface 102 of the wafer 100 becomes a grinding surface on which a grinding process is performed.

[0016] The grinding device 1 includes a first device base 10, a second device base 11 disposed behind the first device base 10 (on the +Y direction side), and a control unit 7 that controls each member of the grinding device 1.

[0017] The upper surface of the second device base 11 includes a loading / unloading area K1 where the wafer 100 is loaded and unloaded, and a processing area K2. In the processing area K2, a rough grinding mechanism 30 or a finish grinding mechanism 31 grinds the wafer 100 held on the chuck table 5.

[0018] A first cassette stage 150 and a second cassette stage 151 are provided on the front side (-Y direction side) of the first equipment base 10. A first cassette 150a that contains unprocessed wafers 100 is placed on the first cassette stage 150. A second cassette 151a that contains processed wafers 100 is placed on the second cassette stage 151. The first cassette 150a and the second cassette 151a each have a plurality of shelves therein, with one wafer 100 accommodated on each shelf.

[0019] The openings (not shown) of the first cassette 150a and the second cassette 151a face the +Y direction. A robot 155 is disposed on the +Y direction side of these openings. The robot 155 carries the processed wafer 100 into the second cassette 151a. The robot 155 also takes out the unprocessed wafer 100 from the first cassette 150a and places it on the temporary placement table 152.

[0020] A carry-in mechanism 153 is provided at a position adjacent to the temporary placement table 152. The carry-in mechanism 153 is equipped with a suction pad having a suction surface that suction-holds the back surface 102 of the wafer 100. The carry-in mechanism 153 is rotatable within the XY plane and is also movable or extendable along the arrows C1 and C2. The carry-in mechanism 153 suction-holds the wafer 100 temporarily placed on the temporary placement table 152 with the suction pad, transports the wafer 100 to the chuck table 5 located in the carry-in / out area K1 near the temporary placement table 152, and places it on the holding surface 50 of the chuck table 5.

[0021] The chuck table 5 has a holding surface 50 for holding the wafer 100. The holding surface 50 is connected to a suction source (not shown) and is capable of holding the wafer 100 by suction via the protective tape 103. That is, the chuck table 5 holds the wafer 100 by means of the holding surface 50.

[0022] 2, the chuck table 5 has a substantially disk-shaped frame 53, and has a holding portion 51 made of a porous material in a recess provided in the frame 53. The upper surface of the holding portion 51 serves as the holding surface 50 described above. A frame surface 54, which is the upper surface of the frame 53, surrounds the holding surface 50 and is formed to be flush with the holding surface 50. A table base 55 that supports the frame 53 is disposed below the frame 53.

[0023] As shown in FIG. 1, the chuck table 5, with the wafer 100 held on the holding surface 50, is rotatable, for example, in the direction of arrow A1 about a rotation axis that passes through the center of the holding surface 50 and extends in the Z-axis direction.

[0024] The chuck table 5 is also capable of suction-holding the dressing board 120 shown in Fig. 3 by the holding surface 50. That is, the chuck table 5 is an example of a table that holds the dressing board 120. The dressing board 120 is used to perform dressing of the rough grinding wheel 306 of the rough grinding mechanism 30 and the finish grinding wheel 316 of the finish grinding mechanism 31.

[0025] In this embodiment, three chuck tables 5 are disposed at equal intervals in the circumferential direction on the upper surface of a turntable 6 disposed on a second device base 11. The turntable 6 can rotate, for example, in the direction of arrow A2 about a rotation axis that passes through its center and extends in the Z-axis direction. The rotation of the turntable 6 causes the three chuck tables 5 to revolve. This allows the chuck tables 5 to be sequentially positioned near the temporary placement table 152 in the carry-in / out area K1 and below the rough grinding mechanism 30 and the finish grinding mechanism 31 in the processing area K2.

[0026] A support pillar 14 is erected on the rear (+Y direction side) of the second device base 11. A first guide surface 15 and a second guide surface 16 are formed on the -Y side of the support pillar 14.

[0027] A first slider 12 is attached to a first guide surface 15 of the support column 14 so as to be movable in a horizontal direction (the direction of the double arrow E1) via a first horizontal movement mechanism 25 (see also FIG. 4). A rough grinding mechanism 30 for rough grinding the wafer 100 and a rough grinding feed mechanism 20 are disposed in front of the first slider 12.

[0028] The rough grinding feed mechanism 20 moves the chuck table 5 and the rough grinding mechanism 30 relatively in the Z-axis direction, which is a direction perpendicular to the holding surface 50. In this embodiment, the rough grinding feed mechanism 20 moves the rough grinding mechanism 30 in the Z-axis direction relative to the chuck table 5.

[0029] The rough grinding feed mechanism 20 includes a pair of guide rails 201 parallel to the Z-axis direction, a lifting table 203 that slides on the guide rails 201, a ball screw 200 parallel to the guide rails 201, a motor 202 that rotates the ball screw 200, and a holder 204 attached to the lifting table 203. The holder 204 holds the rough grinding mechanism 30.

[0030] The lift table 203 is slidably installed on the guide rail 201. A nut portion (not shown) is fixed to the lift table 203. A ball screw 200 is screwed into the nut portion. The motor 202 is connected to one end of the ball screw 200.

[0031] In the rough grinding feed mechanism 20, the motor 202 rotates the ball screw 200, causing the lifting table 203 to move in the Z-axis direction along the guide rail 201. As a result, the holder 204 attached to the lifting table 203 and the rough grinding mechanism 30 held by the holder 204 also move in the Z-axis direction together with the lifting table 203.

[0032] The rough grinding mechanism 30 includes a spindle housing 301 fixed to the holder 204, a spindle 300 rotatably held in the spindle housing 301, a motor 302 that rotates the spindle 300, a wheel mount 303 attached to the lower end of the spindle 300, and a grinding wheel 304 detachably connected to the lower surface of the wheel mount 303.

[0033] The spindle housing 301 is held by the holder 204 so as to extend in the Z-axis direction. The spindle 300 extends in the Z-axis direction so as to be perpendicular to the holding surface 50 of the chuck table 5, and is supported by the spindle housing 301 so as to be rotatable.

[0034] The motor 302 is connected to the upper end side of the spindle 300. The motor 302 rotates the spindle 300 about a rotation axis extending in the Z-axis direction.

[0035] The wheel mount 303 is formed in a disk shape, and is fixed to the lower end (tip) of the spindle 300. The wheel mount 303 supports the grinding wheel 304.

[0036] The grinding wheel 304 includes a wheel base 305 formed from a metal material. A rough grinding wheel (rough grinding wheel) 306 is arranged in a ring shape and fixed to the lower surface of the wheel base 305 around the entire circumference. The ring-shaped rough grinding wheel 306 grinds the wafer 100 or the dressing board 120 held on the chuck table 5. The rough grinding wheel 306 is a grinding wheel containing relatively large abrasive grains.

[0037] Further, the second slider 13 is attached to the second guide surface 16 of the support column 14 so as to be movable in the horizontal direction (the direction of the double arrow E2) via a second horizontal movement mechanism 35 (see FIG. 4). A finish grinding mechanism 31 that finish-grinds the wafer 100 and a finish grinding feed mechanism 21 are disposed in front of the second slider 13.

[0038] The finish grinding feed mechanism 21 moves the chuck table 5 and the finish grinding mechanism 31 relatively in the Z-axis direction, which is a direction perpendicular to the holding surface 50. In this embodiment, the finish grinding feed mechanism 21 moves the finish grinding mechanism 31 in the Z-axis direction relative to the chuck table 5.

[0039] The finish grinding feed mechanism 21 has a similar configuration to the rough grinding feed mechanism 20. That is, the finish grinding feed mechanism 21 includes a guide rail 211, a lift table 213, a ball screw 210, a motor 212, and a holder 214, which correspond to the guide rail 201, the lift table 203, the ball screw 200, the motor 202, and the holder 204 of the rough grinding feed mechanism 20.

[0040] The finish grinding mechanism 31 has the same configuration as the rough grinding mechanism 30, except that it is provided with a finishing grindstone 316 instead of the rough grindstone 306. That is, the finish grinding mechanism 31 is provided with a spindle housing 311, a spindle 310, a motor 312, a wheel mount 313, and a grinding wheel 314, which correspond to the spindle housing 301, the spindle 300, the motor 302, the wheel mount 303, and the grinding wheel 304 of the rough grinding mechanism 30. The grinding wheel 314 includes a wheel base 315 corresponding to the wheel base 305, and a ring-shaped finishing grindstone (finish grinding grindstone) 316. The finishing grindstone 316 is a grinding grindstone containing relatively small abrasive grains, and is arranged and fixed in a ring shape around the entire circumference on the lower surface of the wheel base 315.

[0041] The first horizontal movement mechanism 25 (see FIGS. 1 and 4) moves the chuck table 5 and the rough grinding mechanism 30 relatively in a horizontal direction parallel to the holding surface 50. In this embodiment, the first horizontal movement mechanism 25 is disposed on the first guide surface 15 of the support column 14, and supports the first slider 12 that holds the rough grinding mechanism 30. The first horizontal movement mechanism 25 can move the first slider 12 horizontally along the first guide surface 15 relative to the chuck table 5, as indicated by the double-headed arrow E1 (see FIG. 1). With the movement of the first slider 12, the center of the rough grindstone 306 can move on a straight line connecting the center of the chuck table 5 located below the rough grinding mechanism 30 and the center of the turntable 6.

[0042] The second horizontal movement mechanism 35 (see FIGS. 1 and 4) moves the chuck table 5 and the finish grinding mechanism 31 relatively in a horizontal direction parallel to the holding surface 50. In this embodiment, the second horizontal movement mechanism 35 is disposed on the second guide surface 16 of the support column 14, and supports the second slider 13 that holds the finish grinding mechanism 31. The second horizontal movement mechanism 35 can move the second slider 13 horizontally along the second guide surface 16 relative to the chuck table 5, as indicated by the double-headed arrow E2 (see FIG. 1). With the movement of the second slider 13, the center of the finishing grindstone 316 can move on a straight line connecting the center of the chuck table 5 located below the finish grinding mechanism 31 and the center of the turntable 6.

[0043] After the finish grinding, the wafer 100 is positioned in the carry-in / out area K1 shown in FIG. 1 together with the chuck table 5 by the rotation of the turntable 6, and is carried out by the carry-out mechanism 154. The carry-out mechanism 154 is provided with a suction pad having a suction surface that suction-holds the back surface 102 of the wafer 100. The carry-out mechanism 154 is rotatable within the XY plane, and is also movable or extendable along the double arrows D1 and D2. The carry-out mechanism 154 suction-holds the back surface 102 of the wafer 100 after the finish grinding, which is placed on the chuck table 5, by the suction pad. Thereafter, the carry-out mechanism 154 carries the wafer 100 out of the chuck table 5 and transports it to a single-wafer type spinner cleaning unit 156.

[0044] In the spinner cleaning unit 156, the wafer 100 is held by a spinner table 157, and cleaning water and dry air are sprayed onto the wafer 100. In this way, the wafer 100 is cleaned and dried. The wafer 100 cleaned by the spinner cleaning unit 156 is carried by the robot 155 into the second cassette 151a.

[0045] A first thickness measuring device 80 is disposed at a position adjacent to the chuck table 5 disposed below the rough grinding mechanism 30. The first thickness measuring device 80 measures the thickness of the wafer 100 in a contact manner during rough grinding.

[0046] That is, the first thickness measuring device 80 includes a first holding surface sensor 81 and a first wafer sensor 82. The first holding surface sensor 81 measures the height of the holding surface 50 of the chuck table 5 arranged below the rough grinding mechanism 30. The first wafer sensor 82 measures the height of the wafer 100 held on the holding surface 50. This allows the first thickness measuring device 80 to measure the thickness of the wafer 100 during rough grinding based on the difference between the height of the holding surface 50 of the chuck table 5 and the height of the wafer 100.

[0047] The first thickness measuring device 80 may be configured as a non-contact measuring device. In this case, the first thickness measuring device 80, for example, irradiates the wafer 100 with a laser beam having a wavelength that is transparent to the wafer 100, and measures the thickness of the wafer 100 based on the light reflected by the bottom surface of the wafer 100 and the lower surface of the wafer 100.

[0048] Meanwhile, a second thickness gauge 90 is disposed at a position adjacent to the chuck table 5 disposed below the finish grinding mechanism 31. The second thickness gauge 90 measures the thickness of the wafer 100 in a contact manner during finish grinding. The second thickness gauge 90 has a second holding surface sensor 91 and a second wafer sensor 92, which have the same functions as the first holding surface sensor 81 and the first wafer sensor 82 of the first thickness gauge 80.

[0049] That is, in the second thickness measuring device 90, the second holding surface sensor 91 measures the height of the holding surface 50 of the chuck table 5 arranged below the finish grinding mechanism 31. In addition, the second wafer sensor 92 measures the height of the wafer 100 held on the holding surface 50. This allows the second thickness measuring device 90 to measure the thickness of the wafer 100 during finish grinding based on the difference between the height of the holding surface 50 of the chuck table 5 and the height of the wafer 100. Similarly to the first thickness measuring device 80, the second thickness measuring device 90 may be configured as a non-contact type thickness measuring device.

[0050] The control unit 7 includes a CPU that performs calculation processing according to a program, and a storage medium such as a memory, etc. The control unit 7 controls each component of the grinding device 1 described above to perform grinding processing on the wafer 100. Furthermore, the control unit 7 performs dressing of the rough grindstone 306 of the rough grinding mechanism 30 and the finish grindstone 316 of the finish grinding mechanism 31 using the dressing board 120 shown in FIG.

[0051] Here, the configuration of the dressing board 120 will be described. The dressing board 120 shown in Fig. 3 is for dressing the rough grindstone 306 and the finish grindstone 316, which are grindstones for grinding the wafer 100. The dressing board 120 has a first dress grindstone 121 for shaping, which contains first abrasive grains fixed with a first bond material, a second dress grindstone 122 for dressing, which is disposed below the first dress grindstone 121 and contains second abrasive grains fixed with a second bond material, and a disk-shaped base 123 disposed below the second dress grindstone 122. That is, the dressing board 120 is formed by stacking the base 123, the second dress grindstone 122, and the first dress grindstone 121 in this order.

[0052] The base 123 has a size (diameter) capable of covering the holding surface 50 of the chuck table 5, for example, approximately the same diameter as the holding surface 50. The first dressing grindstone 121 has a disk shape with a diameter smaller than that of the base 123, and contains first abrasive grains and a first bond material for fixing the first abrasive grains. The second dressing grindstone 122 also has a disk shape with approximately the same diameter as the first dressing grindstone 121, and contains second abrasive grains and a second bond material for fixing the second abrasive grains. The first dressing grindstone 121 and the second dressing grindstone 122 are stacked in the center of the base 123.

[0053] In this embodiment, the first abrasive grains of the first dressing grindstone 121 are larger (having a larger diameter) than the second abrasive grains of the second dressing grindstone 122. Therefore, in this embodiment, the first dressing grindstone 121 functions as a dressing grindstone for shaping the grinding wheels (roughing grindstone 306 and finishing grindstone 316). In addition, the second dressing grindstone 122 functions as a dressing grindstone for sharpening the shaped grinding wheels.

[0054] Next, a method for dressing the grinding wheels according to this embodiment will be described. This dressing method is a method for dressing the ring-shaped rough grinding wheel 306 and the finishing grinding wheel 316 for grinding the wafer 100, which is a workpiece, by using a dressing board 120. This dressing method is carried out, for example, before the start of grinding (TAIKO grinding) of the wafer 100 by the grinding device 1.

[0055] (1) Holding process First, a holding step is performed. In this step, the dressing board 120 is held by the chuck table 5 so that the first dress grindstone 121 faces upward.

[0056] Specifically, the worker stores the dressing board 120 in the first cassette 150a shown in Fig. 1. Then, the control unit 7 controls the robot 155 to take out the dressing board 120 from the first cassette 150a and place it on the temporary placement table 152. Alternatively, the dressing board 120 may be placed on the temporary placement table 152 by an operator without using the first cassette 150a and the robot 155.

[0057] Thereafter, the control unit 7 causes the loading mechanism 153 to hold the dressing board 120 on the temporary placement table 152, and places the dressing board 120 on the holding surface 50 of the chuck table 5 arranged in the loading / unloading area K1 so that the first dress grindstone 121 faces upward. Then, the control unit 7 connects the holding surface 50 to a suction source (not shown). As a result, the dressing board 120 is held by the chuck table 5, as shown in FIG. 2.

[0058] (2) Rough grindstone dressing process (2-1) First dressing process After the holding step, a rough grindstone dressing step is performed to dress the rough grindstone 306. First, a first dressing step is performed. In this step, the rough grindstone 306 is lowered to cut into the first dressing grindstone 121 of the dressing board 120.

[0059] Specifically, the control unit 7 rotates the turntable 6 shown in Fig. 1, thereby positioning the chuck table 5 holding the dressing board 120 below the rough grinding mechanism 30 in the processing area K2, as shown in Fig. 4. In addition, the control unit 7 controls the first horizontal movement mechanism 25 to position the rough grinding wheel 306 of the rough grinding mechanism 30 directly above the first dressing grinding wheel 121 of the dressing board 120.

[0060] Next, the control unit 7 drives the motor 302 of the rough grinding mechanism 30 to rotate the spindle 300. This rotates the wheel mount 303 and the grinding wheel 304 attached to the lower end of the spindle 300. In this state, the control unit 7 causes the rough grinding mechanism 30 to move down along the Z-axis direction by the rough grinding feed mechanism 20. At this time, the control unit 7 keeps the rotation of the chuck table 5 stopped.

[0061] 5, the rough grindstone 306 of the rotating grinding wheel 304 comes into contact with the first dress grindstone 121 for shaping on the dressing board 120 held on the chuck table 5, and cuts into the first dress grindstone 121. As a result, the rough grindstone 306 is shaped by the first dress grindstone 121.

[0062] (2-2) Second dressing process After the first dressing step, the second dressing step is performed. In this step, the rough grindstone 306 is lowered continuously from the first dressing step and cuts into the second dressing grindstone 122 below the first dressing grindstone 121 on the dressing board 120. That is, in the second dressing step, the rough grindstone 306 cuts through the first dressing grindstone 121 and grinds the second dressing grindstone 122.

[0063] Specifically, after the first dressing step, the control unit 7 causes the rough grinding mechanism 30 to further descend along the Z-axis direction by the rough grinding feed mechanism 20 while maintaining the rotation of the grinding wheel 304. As a result, as shown in Fig. 6, the rough grindstone 306 of the rotating grinding wheel 304 comes into contact with the second dress grindstone 122 for dressing on the dressing board 120 held on the chuck table 5, and cuts into the second dress grindstone 122. As a result, the rough grindstone 306 is dressed by the second dress grindstone 122.

[0064] In this manner, the coarse grindstone dressing process for dressing the coarse grindstone 306 is completed. After the coarse grindstone dressing process, as shown in FIG. 7, the first dressing grindstone 121 and the second dressing grindstone 122 of the dressing board 120 have cut grooves 125 formed by the cutting of the coarse grindstone 306.

[0065] (3) Finishing stone dressing process After the roughing grindstone dressing step, a finishing grindstone dressing step is performed to dress the finishing grindstone 316. That is, the first and second dressing steps similar to those performed on the roughing grindstone 306 are performed on the finishing grindstone 316. (3-1) First dressing process First, a first dressing step is performed. In this step, the finishing grindstone 316 is lowered to cut into the first dressing grindstone 121 of the dressing board 120.

[0066] Specifically, the control unit 7 rotates the turntable 6 shown in Fig. 1, thereby positioning the chuck table 5 holding the dressing board 120 below the finish grinding mechanism 31 in the processing area K2, as shown in Fig. 4. In addition, the control unit 7 controls the second horizontal movement mechanism 35 to position the finishing grindstone 316 of the finish grinding mechanism 31 directly above the first dressing grindstone 121 of the dressing board 120.

[0067] At this time, the control unit 7 adjusts the positional relationship between the dressing board 120 and the finishing grindstone 316, for example by slightly rotating the chuck table 5, so as to avoid the finishing grindstone 316 getting stuck in (or coming into contact with) the cut groove 125 shown in Figure 7.

[0068] Next, the control unit 7 drives the motor 312 of the finish grinding mechanism 31 to rotate the spindle 310. This rotates the wheel mount 313 and the grinding wheel 314 attached to the lower end of the spindle 310. In this state, the control unit 7 causes the finish grinding mechanism 31 to move down along the Z-axis direction by the finish grinding feed mechanism 21. At this time, the control unit 7 keeps the rotation of the chuck table 5 stopped.

[0069] 5, the finishing grindstone 316 of the rotating grinding wheel 314 comes into contact with the first dressing grindstone 121 for shaping on the dressing board 120 held on the chuck table 5, and cuts into the first dressing grindstone 121. As a result, the finishing grindstone 316 is shaped by the first dressing grindstone 121.

[0070] (3-2) Second dressing process After the first dressing step, a second dressing step is performed. In this step, the finishing grindstone 316 is lowered continuously from the first dressing step and cuts into the second dressing grindstone 122 below the first dressing grindstone 121 on the dressing board 120. That is, in the second dressing step, the finishing grindstone 316 cuts through the first dressing grindstone 121 and grinds the second dressing grindstone 122.

[0071] Specifically, after the first dressing step, the control unit 7 causes the finish grinding mechanism 31 to further descend along the Z-axis direction by the finish grinding feed mechanism 21 while maintaining the rotation of the grinding wheel 314. As a result, as shown in Fig. 6, the finishing grindstone 316 of the rotating grinding wheel 314 comes into contact with the second dress grindstone 122 for sharpening on the dressing board 120 held on the chuck table 5, and cuts into the second dress grindstone 122. As a result, the finishing grindstone 316 is sharpened by the second dress grindstone 122. In this manner, the finishing wheel dressing process for dressing the finishing wheel 316 is completed.

[0072] As described above, in this embodiment, the dressing board 120 has the first dressing grindstone 121 for shaping and the second dressing grindstone 122 for dressing arranged below the first dressing grindstone 121. Therefore, by lowering the grinding wheels while grinding the dressing board 120 with the rotating grinding wheels (rough grindstone 306 and finishing grindstone 316), the grinding wheels can be cut into the first dressing grindstone 121 for shaping and the second dressing grindstone 122 for dressing in this order. Therefore, in this embodiment, the shaping and dressing of the grinding wheels can be easily performed without moving the grinding wheels in the horizontal direction. Therefore, it is possible to shorten the dressing time of the grinding wheels.

[0073] In this embodiment, the chuck table 5 that holds the dressing board 120 is not rotated in the first dressing step and the second dressing step. Therefore, by changing the position (orientation) of the dressing board 120 where the grinding wheel comes into contact, dressing by the dressing board 120 can be performed multiple times.

[0074] Furthermore, in a grinding apparatus that performs TAIKO grinding such as the grinding apparatus 1, corners between the bottom surface and side surface of the grinding wheel tend to be rounded. For this reason, the dressing method according to this embodiment is particularly effective. However, the grinding device in which the dressing method using the dressing board 120 according to the present embodiment is carried out is not limited to a grinding device that performs TAIKO grinding. In other words, the dressing method using the dressing board 120 can be carried out in any grinding device that has a table that holds the dressing board 120 and a grinding wheel.

[0075] In this embodiment, the rough grindstone 306 and the finish grindstone 316 are dressed using the dressing board 120 held by the chuck table 5. Alternatively, the dressing may be performed using the dresser 60 shown in Figs. 1 and 8.

[0076] The dresser 60 is disposed near the rough grinding mechanism 30 and the finish grinding mechanism 31 on the second device base 11. The dresser 60 includes a cylinder member 61, which is a lifting unit, and a sub-chuck table 65 attached to the cylinder member 61, as shown in FIG.

[0077] The cylinder member 61 includes a cylindrical cylinder body 62 disposed on the second device base 11 , and a piston rod 63 disposed within the cylinder body 62 . The piston rod 63 can be moved up and down along the Z-axis direction within the cylinder body 62 by a driving member (not shown).

[0078] The sub-chuck table 65 is an example of a table that holds the dressing board 120. The sub-chuck table 65 has a substantially disk-shaped frame body 67, and has a holding portion 66 made of a porous material in a recess provided in the frame body 67. The upper surface of the holding portion 66 serves as a holding surface 68 that holds the dressing board 120. The holding surface 68 is connected to a suction source (not shown) so that it is possible to hold the dressing board 120 by suction.

[0079] The dressing board 120 held by the sub-chuck table 65 is formed to have a size corresponding to the size (diameter) of the sub-chuck table 65. That is, the base 123 of the dressing board 120 has a size (diameter) capable of covering the holding surface 68. In this case, the base 123 may have approximately the same diameter as the second dress grindstone 122 and the first dress grindstone 121.

[0080] The sub-chuck table 65 is attached to the tip (upper end) of the piston rod 63. The movement range of the piston rod 63 in the Z-axis direction is from a position where the dressing board 120 held by the sub-chuck table 65 attached to the tip is above the wafer 100 held on the holding surface 50 of the chuck table 5 to a position where the dressing board 120 is below the holding surface 50. In this embodiment, for example, when dressing is performed using the dressing board 120, the dressing board 120 is positioned above the holding surface 50 of the chuck table 5 (see FIG. 9). On the other hand, during grinding processing of the wafer 100, the dressing board 120 is positioned below the holding surface 50 (see FIG. 8).

[0081] The dressers 60 having such a configuration are disposed on the second apparatus base 11, one near the rough grinding mechanism 30 and one near the finish grinding mechanism 31. In this embodiment, the rough grinding mechanism 30 is moved horizontally by the first horizontal movement mechanism 25, so that the rough grinding wheel 306 can be disposed above the dresser 60 on the rough grinding mechanism 30 side. In addition, the finish grinding mechanism 31 is moved horizontally by the second horizontal movement mechanism 35, so that the finish grinding wheel 316 can be disposed above the dresser 60 on the finish grinding mechanism 31 side.

[0082] Here, a dressing method using the dresser 60 will be described. In this embodiment, as described above, the grinding apparatus 1 is configured to perform so-called TAIKO grinding on the wafer 100. That is, the rough grinding mechanism 30 forms a circular recess and an annular protrusion on the wafer 100 held on the chuck table 5, and the finish grinding mechanism 31 finish-grinds the bottom surface of the circular recess formed in the wafer 100.

[0083] At the start or end of such TAIKO grinding, or during the grinding, the control unit 7 performs dressing of the rough grindstone 306 and the finishing grindstone 316.

[0084] (1) Holding process In the dressing using the dresser 60, a holding process is first performed. In this process, the dressing board 120 is held by the sub-chuck tables 65 of the two dressers 60 so that the first dress grindstone 121 faces upward. Specifically, the operator or the control unit 7 places the dressing board 120 on the holding surfaces 68 of the two sub-chuck tables 65 so that the first dress grindstone 121 faces upward. Thereafter, the control unit 7 connects the holding surfaces 68 to a suction source (not shown). As a result, the dressing board 120 is held by the chuck table 5 as shown in FIG. 8. It is preferable that this holding step be carried out before the start of the TAIKO grinding process.

[0085] (2) Rough grindstone dressing process After the holding step, at a predetermined timing, the control unit 7 performs a coarse grindstone dressing step of dressing the coarse grindstone 306. The timing of performing this step may be at the start or end of the TAIKO grinding process, or may be during the grinding process for the wafer 100, as shown in FIG.

[0086] (2-1) First dressing process First, a first dressing step is performed. In this step, the rough grindstone 306 is lowered to cut into the first dressing grindstone 121 of the dressing board 120.

[0087] 9, the control unit 7 moves the piston rod 63 of the cylinder member 61 in the dresser 60 on the rough grinding mechanism 30 side upward, thereby raising the dressing board 120 held on the sub-chuck table 65 above the wafer 100 held on the holding surface 50 of the chuck table 5. At this time, if the wafer 100 is not held on the holding surface 50, the control unit 7 only needs to raise the dressing board 120 above the holding surface 50. Furthermore, the control unit 7 controls the first horizontal movement mechanism 25 to position the rough grindstone 306 of the rough grinding mechanism 30 directly above the first dress grindstone 121 of the dressing board 120.

[0088] Next, the control unit 7 drives the motor 302 of the rough grinding mechanism 30 to rotate the spindle 300. This rotates the wheel mount 303 and the grinding wheel 304 attached to the lower end of the spindle 300. In this state, the control unit 7 causes the rough grinding mechanism 30 to move down along the Z-axis direction by the rough grinding feed mechanism 20.

[0089] As a result, the rough grindstone 306 of the rotating grinding wheel 304 comes into contact with the first dress grindstone 121 for shaping on the dressing board 120 held by the sub-chuck table 65, and cuts into the first dress grindstone 121. As a result, the rough grindstone 306 is shaped by the first dress grindstone 121.

[0090] (2-2) Second dressing process After the first dressing step, a second dressing step is performed. In this step, the rough grindstone 306 is lowered continuously from the first dressing step and cuts into the second dressing grindstone 122 below the first dressing grindstone 121 on the dressing board 120.

[0091] Specifically, after the first dressing step, the control unit 7 causes the rough grinding mechanism 30 to further descend along the Z-axis direction by the rough grinding feed mechanism 20 while maintaining the rotation of the grinding wheel 304. As a result, the rough grindstone 306 of the rotating grinding wheel 304 cuts through the first dress grindstone 121 on the dressing board 120, contacts the second dress grindstone 122 for sharpening, and cuts into the second dress grindstone 122. As a result, the rough grindstone 306 is sharpened by the second dress grindstone 122. In this manner, the coarse grindstone dressing step of dressing the coarse grindstone 306 is completed.

[0092] (3) Finishing stone dressing process After the holding step, the control unit 7 performs a finishing grindstone dressing step at a predetermined timing to dress the finishing grindstone 316. This step may be performed at the start or end of the TAIKO grinding process, or during the grinding process. In the finishing grindstone dressing step, the finishing grindstone 316 is subjected to a first dressing step and a second dressing step similar to those performed for the rough grindstone 306.

[0093] (3-1) First dressing process In the first dressing process, the control unit 7 moves the piston rod 63 of the cylinder member 61 in the dresser 60 on the finish grinding mechanism 31 side upward, thereby raising the dressing board 120 held on the sub-chuck table 65 above the holding surface 50 of the chuck table 5 or the wafer 100 held on the holding surface 50. Furthermore, the control unit 7 controls the second horizontal movement mechanism 35 to position the finishing grindstone 316 of the finish grinding mechanism 31 directly above the first dressing grindstone 121 of the dressing board 120.

[0094] Next, the control unit 7 lowers the finish grinding mechanism 31 along the Z-axis direction while rotating the grinding wheel 314. As a result, the finishing grindstone 316 of the rotating grinding wheel 314 comes into contact with the first dressing grindstone 121 for shaping on the dressing board 120 and cuts into the first dressing grindstone 121. As a result, the finishing grindstone 316 is shaped by the first dressing grindstone 121.

[0095] (3-2) Second dressing process After the first dressing step, the control unit 7 causes the finish grinding mechanism 31 to further descend along the Z-axis direction by the finish grinding feed mechanism 21 while maintaining the rotation of the grinding wheel 314. As a result, the rotating finishing grindstone 316 cuts through the first dressing grindstone 121 on the dressing board 120, contacts the second dressing grindstone 122 for sharpening, and cuts into the second dressing grindstone 122. As a result, the finishing grindstone 316 is sharpened by the second dressing grindstone 122. In this manner, the finishing wheel dressing process for dressing the finishing wheel 316 is completed.

[0096] In this way, even in dressing using the sub-chuck table 65, the grinding wheels (roughing wheel 306 and finishing wheel 316) can be lowered while grinding the dressing board 120 with the rotating grinding wheels, so that the grinding wheels can cut into the first dressing wheel 121 for shaping and the second dressing wheel 122 for dressing in that order. Therefore, shaping and dressing of the grinding wheels can be easily performed without moving the grinding wheels horizontally. This makes it possible to shorten the dressing time of the grinding wheels.

[0097] In this embodiment, the first abrasive grains contained in the first dress grindstone 121 for shaping are larger than the second abrasive grains contained in the second dress grindstone 122 for dressing. However, instead of or in addition to the first abrasive grains being larger than the second abrasive grains, the first dress grindstone 121 may be configured as a dress grindstone for shaping and the second dress grindstone 122 may be configured as a dress grindstone for dressing by other factors.

[0098] For example, the first dress grindstone 121 may have a higher concentration (abrasive grain density) than the second dress grindstone 122. Alternatively, the first dress grindstone 121 may be configured to be harder than the second dress grindstone 122. This also makes it possible to configure the first dress grindstone 121 as a dress grindstone for shaping, and the second dress grindstone 122 as a dress grindstone for sharpening.

[0099] Here, the first dressing grindstone 121 being harder than the second dressing grindstone 122 is achieved, for example, by the first abrasive grains contained in the first dressing grindstone 121 being harder than the second abrasive grains contained in the second dressing grindstone 122, and / or the first bond material contained in the first dressing grindstone 121 being harder than the second bond material contained in the second dressing grindstone 122.

[0100] Furthermore, the first abrasive grains being harder than the second abrasive grains can be realized, for example, by using diamond abrasive grains as the first abrasive grains and GC (green carbonite) abrasive grains as the second abrasive grains. Note that sapphire or SiC may be used as the first abrasive grains and WA (white alundum) as the second abrasive grains. Note that GC may be used as the first abrasive grains and WA as the second abrasive grains. Furthermore, the first bond material being harder than the second bond material can be realized, for example, by using a metal bond material as the first bond material and a resin bond material as the second bond material.

[0101] Fig. 10 shows examples (cases 1 to 4) of preferred combinations of the first abrasive grains, the first bond material, the second abrasive grains, and the second bond material. In this figure, "same" in cases 1 to 3 means that the hardness of the first bond material and the second bond material are substantially equal. Also, "same" in case 4 means that the hardness and particle size of the first abrasive grains and the second abrasive grains are substantially equal.

[0102] As shown in Case 2, even if the abrasive grain size of the first abrasive grains and the second abrasive grains are equal, if the first abrasive grains are harder than the second abrasive grains, the first dressing grindstone 121 will be harder than the second dressing grindstone 122, and the first dressing grindstone 121 can be configured as a dressing grindstone for shaping, and the second dressing grindstone 122 can be configured as a dressing grindstone for sharpening.

[0103] Thus, it is preferable that the first dressing grindstone 121 has larger abrasive grains, a higher concentration (higher abrasive grain density), and / or a higher hardness (hardness of the abrasive grains or bond) than the second dressing grindstone 122. [Explanation of symbols]

[0104] 1: grinding device, 5: chuck table, 6: turntable, 7: control unit, 10: first device base; 11: second device base; 12: first slider; 13: second slider, 14: support column, 15: first guide surface, 16: second guide surface, 20: rough grinding feed mechanism, 21: finish grinding feed mechanism, 25: first horizontal movement mechanism, 30: rough grinding mechanism, 31: finish grinding mechanism, 35: second horizontal movement mechanism, 50: holding surface, 51: holding portion, 53: frame body, 54: frame body surface, 55: table base, 60: dresser, 61: cylinder member, 62: cylinder body, 63: piston rod, 65: sub-chuck table, 66: holding portion, 67: frame body, 68: holding surface, 80: first thickness measuring device, 81: first holding surface sensor, 82: first wafer sensor, 90: second thickness measuring device, 91: second holding surface sensor, 92: second wafer sensor, 100: wafer, 101: front surface, 102: back surface, 103: protective tape, 120: dressing board, 121: first dressing grindstone, 122: second dressing wheel, 123: base, 125: notch, 150: first cassette stage, 150a: first cassette, 151: second cassette stage, 151a: second cassette, 152: temporary placement table, 153: loading mechanism, 154: unloading mechanism, 155: robot, 156: spinner cleaning unit, 157: spinner table, 200: ball screw, 201: guide rail, 202: motor, 203: lift table, 204: holder, 210: ball screw, 211: guide rail, 212: motor, 213: lift table, 214: holder, 300: spindle, 301: spindle housing, 302: motor; 303: wheel mount; 304: grinding wheel; 305: Wheel base, 306: Rough grindstone, 310: Spindle, 311: spindle housing, 312: motor, 313: wheel mount, 314: grinding wheel, 315: wheel base, 316: Finishing stone, K1: Loading / unloading area, K2: Processing area

Claims

1. A dressing board for dressing a grinding wheel for grinding a workpiece, comprising: a first dressing wheel for shaping, the first dressing wheel including first abrasive grains fixed by a first bond material; and a second dressing stone for dressing, which is disposed under the first dressing stone and includes second abrasive grains fixed with a second bond material. Dressing board.

2. The first abrasive grains are larger than the second abrasive grains; A dressing board as described in claim 1.

3. The first dressing stone has a higher concentration than the second dressing stone. A dressing board as described in claim 1.

4. The first dressing stone is harder than the second dressing stone; A dressing board as described in claim 1.

5. The first abrasive grains are harder than the second abrasive grains; A dressing board according to claim 4.

6. The first bond material is harder than the second bond material; A dressing board according to claim 4.

7. A method for dressing a ring-shaped grinding wheel for grinding a workpiece using the dressing board according to claim 1, comprising the steps of: a holding step of holding the dressing board by a table so that the first dress grindstone faces upward; a first dressing step of lowering the grinding wheel so that the grinding wheel cuts into the first dressing wheel of the dressing board; A second dressing step in which the grinding wheel is lowered from the first dressing step and cuts into the second dressing wheel below the first dressing wheel on the dressing board; A dressing method comprising the steps of:

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