Grinding equipment

Abstract

To restore a wafer ID in a grinding apparatus without inviting an increase in the size of the apparatus.SOLUTION: A grinding apparatus 1 includes an ID formation unit 110 which executes reading and restoration processing of a wafer ID. The grinding apparatus reads, by a reading unit 130, the wafer ID of a wafer 100 before grinding placed on a temporary mount table 154 by a robot 155. The grinding apparatus restores, by a laser processing unit 135, the wafer ID in the wafer 100 after grinding placed on the temporary mount table 154 by the robot 155. The grinding apparatus uses the robot 155 and the temporary mount table 154 being an existing configuration in order to execute reading and restoration processing by the ID formation unit 110. Consequently, since configurations to be added for restoration of the wafer ID can be reduced, the wafer ID can be restored in the grinding apparatus 1 without inviting an increase in size.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a grinding device. [Background technology]

[0002] When grinding the backside of a wafer having devices formed on its front side and a wafer ID on its backside, the technology described in Patent Document 1 forms the wafer ID on the front side of the wafer so that the wafer ID does not disappear during grinding. In addition, the technology disclosed in Patent Document 2 restores the wafer ID that has disappeared during grinding to the backside of the wafer after grinding by laser processing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-216274 [Patent Document 2] Japanese Patent Application Publication No. 2018-166177 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology described in Patent Document 2 requires a grinding device, a laser processing device, and a transfer device that transfers wafers from the grinding device to the laser processing device, resulting in a large device configuration.

[0005] Therefore, an object of the present invention is to miniaturize a device for recovering wafer IDs. [Means for solving the problem]

[0006] The grinding apparatus of the present invention (the present grinding apparatus) is a grinding apparatus comprising a chuck table that holds the front side of a wafer having a wafer ID formed on the back side thereof, and a grinding mechanism that grinds the back side of the wafer held by the chuck table with a grinding wheel, and further comprising a reading unit that reads the wafer ID before the chuck table holds the wafer or before the wafer held by the chuck table is ground, and a laser processing unit that restores the wafer ID read by the reading unit to the back side of the ground wafer. The laser processing unit includes a fluid injection nozzle that injects a fluid toward a processing point, which is a portion on the back surface of the wafer where the laser beam is irradiated, and a fluid recovery nozzle that sucks the fluid from the vicinity of the processing point. . The grinding apparatus may include a cassette stage for placing cassettes containing wafers on shelves, a robot for removing wafers from the cassettes on the cassette stage, and a loading mechanism for transporting the wafers removed by the robot to the chuck table, and the reading unit may read the wafer ID of the wafer held by the robot or the wafer held by the loading mechanism. The grinding apparatus may include a temporary placement table for temporarily placing wafers, and the reading unit may read the wafer ID of the wafer temporarily placed on the temporary placement table. The grinding apparatus may include a spinner cleaning mechanism that cleans the wafer ground by the grinding mechanism, and the laser processing unit may be disposed in the spinner cleaning mechanism. [Effects of the Invention]

[0007] This grinding machine is equipped with a reading unit and a laser processing unit, and can transport wafers to the reading unit and the laser processing unit using, for example, existing transport members for transporting wafers to and from the chuck table. Therefore, it is possible to restore the wafer ID within this grinding machine without increasing the size of the machine. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a configuration of a grinding device according to an embodiment. [Figure 2] FIG. 2 is a perspective view showing the configuration of an ID forming unit. [Figure 3] 10 is an explanatory diagram showing the configuration of a Y-axis direction movement mechanism in the ID formation unit. FIG. [Figure 4] FIG. 2 is an explanatory diagram showing a configuration example of a laser processing unit. [Figure 5] FIG. 2 is an explanatory diagram showing an example of the configuration of a processing head in the laser processing unit. [Figure 6] FIG. 10 is an explanatory diagram showing another configuration example of the laser processing unit. DETAILED DESCRIPTION OF THE INVENTION

[0009] As shown in FIG. 1, the grinding apparatus 1 according to this embodiment is an apparatus for grinding a wafer 100 as a workpiece. The wafer 100 is, for example, a circular plate-shaped workpiece, and has a front surface 101 and a back surface 102. A device (not shown) is formed on the front surface 101 of the wafer 100, and a protective tape 103 is attached to the front surface 101. The back surface 102 of the wafer 100 is the surface to be processed and subjected to a grinding process. In addition, a wafer ID (not shown) is formed (stamped) on the back surface 102.

[0010] The grinding device 1 has a first device base 10 and a second device base 11 disposed behind the first device base 10 (on the +Y direction side).

[0011] A first cassette stage 160 and a second cassette stage 162 are provided on the front side (-Y direction side) of the first equipment base 10. A first cassette 161 that stores unprocessed wafers 100 is placed on the first cassette stage 160. A second cassette 163 that stores processed wafers 100 is placed on the second cassette stage 162.

[0012] The first cassette 161 and the second cassette 163 each have a plurality of shelves therein, and each shelf accommodates one wafer 100. That is, the first cassette 161 and the second cassette 163 accommodate a plurality of wafers 100 in a shelf-like manner.

[0013] The openings (not shown) of the first cassette 161 and the second cassette 163 face the +Y direction side. A robot 155 is disposed on the +Y direction side of these openings. The robot 155 includes a holding member 150 that holds the wafer 100. The robot 155 carries (stores) the processed wafer 100 into the second cassette 163. The robot 155 also removes the unprocessed wafer 100 from the first cassette 161 and places it on the temporary placement table 154 of the temporary placement mechanism 152.

[0014] The temporary placement mechanism 152 is used to temporarily place the wafer 100 taken out from the first cassette 161, and is provided at a position adjacent to the robot 155. The temporary placement mechanism 152 has a temporary placement table 154 for temporarily placing the wafer 100, an alignment member 153 for aligning the wafer, and a rotation mechanism 151 for rotating the temporary placement table 154.

[0015] The alignment member 153 includes a plurality of alignment pins arranged on the outside so as to surround the temporary placement table 154, and a slider that moves the alignment pins in the radial direction of the temporary placement table 154. In the alignment member 153, the alignment pins are moved toward the center in the radial direction of the temporary placement table 154, thereby reducing the diameter of a circle connecting the plurality of alignment pins. As a result, the wafer 100 placed on the temporary placement table 154 is aligned (centered) at a predetermined position where the center of the temporary placement table 154 and the center of the wafer 100 coincide with each other.

[0016] An ID forming unit 110 is provided on the +Y direction side of the temporary placement mechanism 152. This ID forming unit 110 will be described later.

[0017] Furthermore, a carry-in mechanism 170 is provided at a position adjacent to the temporary placement mechanism 152. The carry-in mechanism 170 has a suction pad 171 that suction-holds the wafer 100. The carry-in mechanism 170 suction-holds the wafer 100, which has been taken out by the robot 155 and temporarily placed on the temporary placement table 154, using the suction pad 171, and places the wafer 100 on the holding surface 22 of the chuck table 20. In this way, the carry-in mechanism 170 transports the wafer 100 held by the robot 155 to the chuck table 20.

[0018] An opening 13 is provided on the upper surface side of the second apparatus base 11. In the opening 13, a chuck table 20 having a holding surface 22 for holding the wafer 100 is disposed.

[0019] The chuck table 20 includes a porous member 21 and a frame 23 that houses the porous member 21 so that the upper surface of the porous member 21 is exposed. The upper surface of the porous member 21 is a holding surface 22 that holds the wafer 100 by suction. The holding surface 22 is connected to a suction source (not shown) to hold the front surface 101 of the wafer 100 by suction. That is, the chuck table 20 holds the front surface 101 of the wafer 100 by means of the holding surface 22. Furthermore, a frame surface 24, which is the upper surface of the frame 23, surrounds the holding surface 22 and is formed to be flush with the holding surface 22.

[0020] The chuck table 20 can be rotated around a rotation axis passing through the center of the holding surface 22 while holding the wafer 100 on the holding surface 22 by a table rotation mechanism (not shown) provided below the chuck table 20.

[0021] Furthermore, the chuck table 20 can be moved in the Y-axis direction by a table moving mechanism (not shown) provided in the second device base 11. In this embodiment, the chuck table 20 is moved along the Y-axis direction between a workpiece placement position on the -Y direction side for holding the wafer 100 on the holding surface 22 and a grinding position on the +Y direction side where the wafer 100 held on the holding surface 22 is ground.

[0022] A cover plate 39 is provided around the periphery of the chuck table 20 and moves in the Y-axis direction together with the chuck table 20. In addition, a bellows cover 12 that expands and contracts in the Y-axis direction is connected to the cover plate 39.

[0023] Furthermore, a column 15 is erected on the +Y direction side of the second apparatus base 11. In front of the column 15, a grinding mechanism 70 for grinding the wafer 100 and a grinding feed mechanism 60 are provided.

[0024] The grinding feed mechanism 60 moves the chuck table 20 and the grinding wheel 77 of the grinding mechanism 70 relatively in the Z-axis direction (grinding feed direction) perpendicular to the holding surface 22. In this embodiment, the grinding feed mechanism 60 is configured to move the grinding wheel 77 in the Z-axis direction relative to the chuck table 20.

[0025] The grinding feed mechanism 60 includes a pair of Z-axis guide rails 61 parallel to the Z-axis direction, a Z-axis moving table 63 that slides on the Z-axis guide rails 61, a Z-axis ball screw 62 parallel to the Z-axis guide rails 61, a Z-axis motor 64, a Z-axis encoder 65 for detecting the rotation angle of the Z-axis ball screw 62, and a holder 66 attached to the Z-axis moving table 63. The holder 66 supports the grinding mechanism 70.

[0026] The Z-axis moving table 63 is slidably installed on the Z-axis guide rail 61. A nut portion (not shown) is fixed to the Z-axis moving table 63. A Z-axis ball screw 62 is threadedly engaged with this nut portion. A Z-axis motor 64 is connected to one end of the Z-axis ball screw 62.

[0027] In the grinding feed mechanism 60, the Z-axis motor 64 rotates the Z-axis ball screw 62, causing the Z-axis moving table 63 to move in the Z-axis direction along the Z-axis guide rail 61. As a result, the holder 66 attached to the Z-axis moving table 63 and the grinding mechanism 70 supported by the holder 66 also move in the Z-axis direction together with the Z-axis moving table 63.

[0028] Z-axis encoder 65 is rotated by Z-axis motor 64 rotating Z-axis ball screw 62, and can recognize the rotation angle of Z-axis ball screw 62. Based on the recognition result, Z-axis encoder 65 can detect the height position of grinding wheel 77 of grinding mechanism 70, which is moved in the Z-axis direction.

[0029] The grinding mechanism 70 grinds the back surface 102 of the wafer 100 held by the chuck table 20 with a grinding wheel 77. The grinding mechanism 70 includes a spindle housing 71 fixed to the holder 66, a spindle 72 rotatably held by the spindle housing 71, a spindle motor 73 that rotates and drives the spindle 72, a wheel mount 74 attached to the lower end of the spindle 72, and a grinding wheel 75 supported by the wheel mount 74.

[0030] The spindle housing 71 is held by the holder 66 so as to extend in the Z-axis direction. The spindle 72 extends in the Z-axis direction so as to be perpendicular to the holding surface 22 of the chuck table 20, and is rotatably supported by the spindle housing 71.

[0031] The spindle motor 73 is connected to the upper end side of the spindle 72. The spindle motor 73 rotates the spindle 72 about a rotation axis extending in the Z-axis direction.

[0032] The wheel mount 74 is formed in a disk shape and is fixed to the lower end (tip) of the spindle 72. The wheel mount 74 supports the grinding wheel 75.

[0033] The grinding wheel 75 is formed so that its outer diameter is approximately the same as the outer diameter of the wheel mount 74. The grinding wheel 75 includes an annular wheel base 76 made of a metal material. A plurality of grinding stones 77 arranged in an annular shape are fixed to the underside of the wheel base 76 around the entire circumference. The grinding stones 77 are rotated around their center by the spindle motor 73 together with the spindle 72, and grind the back surface 102 of the wafer 100 held on the chuck table 20.

[0034] As shown in FIG. 1, a thickness measuring device 80 is disposed on the side of the opening 13 in the second device base 11.

[0035] The thickness measuring device 80 has a holding surface height gauge 81 and an upper surface height gauge 82. The holding surface height gauge 81 measures the height of the holding surface 22 by contacting the frame surface 24 of the frame 23, which is the same surface as the holding surface 22 of the chuck table 20. The upper surface height gauge 82 measures the height of the back surface 102, which is the height of the upper surface of the wafer 100, by contacting the back surface 102, which is the upper surface of the wafer 100 held on the holding surface 22. The thickness measuring device 80 then calculates the thickness of the wafer 100 based on the difference between the measurement value of the holding surface height gauge 81 and the measurement value of the upper surface height gauge 82.

[0036] The holding surface height gauge 81 and the upper surface height gauge 82 of the thickness measuring device 80 may be non-contact height gauges. For example, the holding surface height gauge 81 and the upper surface height gauge 82 may be configured to measure the height of the holding surface 22 and the height of the back surface 102 of the wafer 100 based on the reflected light (reflected wave) of a laser beam (or sound wave) irradiated onto the frame surface 24 of the frame 23 and the back surface 102 of the wafer 100.

[0037] The ground wafer 100 is carried out by a carry-out mechanism 172. The carry-out mechanism 172 is provided with a suction pad 173 that suction-holds the wafer 100. The carry-out mechanism 172 suction-holds the wafer 100 held on the chuck table 20 by the suction pad 173, and transports the wafer 100 to a spinner table 157 of a single-wafer spinner cleaning mechanism 156.

[0038] The spinner cleaning mechanism 156 is a spinner cleaning unit that cleans the wafer 100 ground by the grinding mechanism 70. The spinner cleaning mechanism 156 includes a spinner table 157 that holds the wafer 100, and a nozzle 158 that sprays cleaning water and dry air toward the spinner table 157.

[0039] In the spinner cleaning mechanism 156, a spinner table 157 holding the wafer 100 rotates, and cleaning water is sprayed toward the wafer 100, thereby spinner-cleaning the wafer 100. Dry air is then blown onto the wafer 100, thereby drying the wafer 100.

[0040] The wafer 100 cleaned by the spinner cleaning mechanism 156 is carried out from the spinner cleaning mechanism 156 by the robot 155 .

[0041] Here, the configuration of the above-mentioned ID formation unit 110 will be described. As shown in FIG. 2, the ID forming unit 110 has a gate-type column 111 that stands on the second device base 11 (see FIG. 1).

[0042] The portal column 111 includes a housing 112 equipped with a reading unit 130 and a laser processing unit 135, and an X-axis direction moving mechanism 120 that moves the housing 112 along the X-axis direction parallel to the temporary placement table 154 of the temporary placement mechanism 152 (see Figure 1).

[0043] The X-axis direction movement mechanism 120 includes a pair of X-axis guide rails 121 parallel to the X-axis direction, an X-axis movement table 123 that slides on the X-axis guide rails 121, an X-axis ball screw 122 parallel to the X-axis guide rails 121, an X-axis motor 124, and an X-axis encoder 125 for detecting the rotation angle of the X-axis ball screw 122.

[0044] X-axis moving table 123 is slidably installed on X-axis guide rail 121, and holds housing 112. X-axis moving table 123 also has a nut portion (not shown). X-axis ball screw 122 is threadedly engaged with this nut portion. X-axis motor 124 is connected to one end of X-axis ball screw 122.

[0045] In X-axis direction movement mechanism 120, X-axis motor 124 rotates X-axis ball screw 122, causing X-axis movement table 123 to move in the X-axis direction along X-axis guide rail 121. As a result, housing 112 held by X-axis movement table 123 also moves in the X-axis direction together with X-axis movement table 123.

[0046] X-axis encoder 125 is rotated by X-axis motor 124 rotating X-axis ball screw 122, and can recognize the rotation angle of X-axis ball screw 122. Then, based on the recognition result, X-axis encoder 125 can detect the position of housing 112 that is moved in the X-axis direction, that is, the positions in the X-axis direction of first camera 131 of reading unit 130 and processing head 136 of laser processing unit 135 that are held in housing 112.

[0047] The reading unit 130 held in the housing 112 is used to read the wafer ID before the chuck table 20 holds the wafer 100 or before the wafer 100 held on the chuck table 20 is ground.

[0048] As shown in Figure 3, the reading unit 130 has a cylindrical first camera 131 arranged outside the housing 112, a ring-shaped light 132 provided at the tip of the first camera 131, and a camera housing 133 that supports the first camera 131.

[0049] Camera housing 133 is provided in housing 112 so as to pass through first opening 134 provided in the surface on the −Y direction side of housing 112. Camera housing 133 has first camera 131 at its tip on the −Y direction side. In addition, the portion of camera housing 133 on the +Y direction side is attached to the upper surface of Y-axis moving table 143, which will be described later.

[0050] The reading unit 130 having such a configuration is configured to capture an image of the back surface 102 of the wafer 100 placed on the temporary placement table 154 (see FIG. 1) of the temporary placement mechanism 152 using the first camera 131, and read the wafer ID formed on the back surface 102. The read wafer ID is stored in the memory unit 8 shown in FIG. 2 inside the housing 112.

[0051] The laser processing unit 135 held in the housing 112 together with the reading unit 130 is used to restore the wafer ID read by the reading unit 130 onto the back surface 102 of the ground wafer 100 . The laser processing unit 135 has a processing head 136 disposed outside the housing 112 and a laser housing portion 137 that supports the processing head 136 .

[0052] The laser housing unit 137 is provided in the housing 112 so as to pass through a second opening 138 provided in the surface on the −Y direction side of the housing 112. The laser housing unit 137 has a processing head 136 at its tip on the −Y direction side. In addition, the portion of the laser housing unit 137 on the +Y direction side is attached to the upper surface of the Y-axis moving table 143.

[0053] The laser processing unit 135 also includes, for example, as shown in FIG. 4, a second camera 187 capable of capturing an image of the wafer 100, a laser oscillator 180 that emits a laser beam 300, a condenser 182, a dichroic mirror 184 that directs the laser beam 300 to the condenser 182, and an elevating mechanism 186 that moves the condenser 182 up and down.

[0054] Of these, for example, the laser oscillator 180 is disposed in the laser housing portion 137 , and the second camera 187 , the dichroic mirror 184 , the condenser 182 and the lifting mechanism 186 are disposed in the processing head 136 .

[0055] In the laser processing unit 135 having such a configuration, the height of the focal point of the laser beam 300 can be adjusted by adjusting the position of the condenser 182 in the Z-axis direction using the elevator mechanism 186. The laser processing unit 135 is configured to form a wafer ID on the back surface 102 of the wafer 100 placed on the temporary placement table 154 of the temporary placement mechanism 152 by irradiating the back surface 102 with a laser beam. Note that the laser beam 300 irradiated from the laser processing unit 135 is, for example, a laser beam having a wavelength that is absorbed by the wafer 100.

[0056] As shown in FIG. 5, the processing head 136 in the laser processing unit 135 may have a fluid ejection nozzle 191 and a fluid recovery nozzle 193 near the tip 139 from which the laser beam 300 is emitted.

[0057] The fluid injection nozzle 191 is connected to a fluid source 192. The fluid injection nozzle 191 injects the fluid supplied from the fluid source 192 toward a processing point 310, which is a portion on the back surface 102 of the wafer 100 that is irradiated with a laser beam 300, as indicated by an arrow 311. The fluid is, for example, air, water, or a mixed fluid of air and water (two-fluid). The fluid injection nozzle 191 may also include a reservoir for temporarily storing water and an ultrasonic vibration plate for propagating ultrasonic vibrations to the water stored in the reservoir. The fluid may be ultrasonic water through which ultrasonic vibrations are propagated.

[0058] The fluid recovery nozzle 193 is connected to a suction source 194. The fluid recovery nozzle 193 sucks fluid from the vicinity of the processing point 310 by the suction force applied by the suction source 194, as shown by arrow 312.

[0059] In the processing head 136 having such a configuration, processing debris generated by processing with the laser beam 300 can be removed from the processing point 310 by the fluid ejected from the fluid ejection nozzle 191. Furthermore, the processing debris removed from the processing point 310 can be collected together with the fluid by suction using the fluid recovery nozzle 193. Therefore, it is possible to effectively remove and collect processing debris from the vicinity of the processing point 310 and the tip of the processing head 136. Therefore, it is possible to prevent the wafer 100 and the processing head 136 from being contaminated by processing debris.

[0060] As shown in FIG. 3, the housing 112 is provided with a Y-axis direction moving mechanism 140 for moving the reading unit 130 and the laser processing unit 135 along the Y-axis direction parallel to the temporary placement table 154 (see FIG. 1) of the temporary placement mechanism 152.

[0061] The Y-axis direction moving mechanism 140 includes a pair of Y-axis guide rails 141 parallel to the Y-axis direction, a Y-axis moving table 143 that slides on these Y-axis guide rails 141, a Y-axis ball screw 142 parallel to the Y-axis guide rails 141, a Y-axis motor 144, a Y-axis encoder 145 for detecting the rotation angle of the Y-axis ball screw 142, and a holding table 146 that holds these.

[0062] Y-axis moving table 143 is slidably installed on Y-axis guide rail 141, and holds camera housing 133 and laser housing 137. Y-axis moving table 143 also has a nut portion (not shown). Y-axis ball screw 142 is threadedly engaged with this nut portion. Y-axis motor 144 is connected to one end of Y-axis ball screw 142.

[0063] In the Y-axis direction moving mechanism 140, the Y-axis motor 144 rotates the Y-axis ball screw 142, causing the Y-axis moving table 143 to move in the Y-axis direction along the Y-axis guide rail 141. As a result, the camera housing 133 and laser housing part 137 held by the Y-axis moving table 143, as well as the first camera 131 and processing head 136 provided at the tip of these, also move in the Y-axis direction together with the Y-axis moving table 143.

[0064] The Y-axis encoder 145 is rotated by the Y-axis motor 144 rotating the Y-axis ball screw 142, and can recognize the rotation angle of the Y-axis ball screw 142. Based on the recognition result, the Y-axis encoder 145 can detect the positions in the Y-axis direction of the first camera 131 and the processing head 136, which are moved in the Y-axis direction.

[0065] 1, the grinding apparatus 1 has a control unit 7 for controlling the grinding apparatus 1. The control unit 7 includes a CPU that performs calculations according to a control program, and a storage medium such as a memory. The control unit 7 executes various processes and controls each component of the grinding apparatus 1. For example, the control unit 7 controls the above-mentioned components of the grinding device 1 to perform the grinding process on the wafer 100.

[0066] The method for grinding the wafer 100 in the grinding apparatus 1, which is controlled by the control unit 7, will be described below.

[0067] [Wafer ID reading process] First, the control unit 7 causes the robot 155 shown in FIG. 1 to take out the unprocessed wafer 100 from the first cassette 161, place it on the temporary placement table 154 of the temporary placement mechanism 152 with the back surface 102 facing upward, and aligns the wafer 100 at a predetermined position.

[0068] Then, the control unit 7 controls the rotation mechanism 151 of the temporary placement mechanism 152, as well as the X-axis direction moving mechanism 120 (see Figure 2) and the Y-axis direction moving mechanism 140 (see Figure 3) in the ID forming unit 110, to position the first camera 131 of the reading unit 130 directly above the wafer ID formed on the back surface 102 of the wafer 100 placed on the temporary placement table 154. The ID formation unit 110 does not necessarily have to include the X-axis direction moving mechanism 120 (see FIG. 2) and the Y-axis direction moving mechanism 140 (see FIG. 3). For example, the wafer 100 aligned to a predetermined position by the alignment member 153 of the temporary placement mechanism 152 may be rotated by the rotation mechanism 151, and the first camera 131 may be positioned directly above the wafer ID.

[0069] Then, the reading unit 130 uses the first camera 131 to capture an image of the wafer ID formed on the back surface 102 while illuminating the back surface 102 with the illumination 132. The reading unit 130 then reads the wafer ID of the wafer 100 from the image obtained by capturing the image, and stores it in the storage unit 8 (see FIG. 2). Thus, in this step, the reading unit 130 reads the wafer ID of the wafer 100 temporarily placed on the temporary placement table 154 .

[0070] [Holding process] 1 at the workpiece holding position on the -Y direction side by controlling the table moving mechanism (not shown). Then, the control unit 7 controls the carry-in mechanism 170 to hold the wafer 100 on the temporary placement mechanism 152 and place it on the holding surface 22 of the chuck table 20 with the back surface 102 facing upward. Thereafter, the control unit 7 controls the table moving mechanism to place the chuck table 20 at a grinding position below the grinding mechanism 70 on the +Y direction side.

[0071] [Grinding process] Next, the control unit 7 rotates the grinding wheel 75 and chuck table 20 of the grinding mechanism 70, and causes the grinding mechanism 70, including the grinding stone 77, to be fed in the -Z direction by the grinding feed mechanism 60. As a result, the grinding stone 77 of the rotating grinding wheel 75 comes into contact with the back surface 102 of the wafer 100 held on the rotating chuck table 20, and grinds this back surface 102.

[0072] In this grinding step, the control unit 7 measures the thickness of the wafer 100 being ground using the thickness measuring device 80. Then, the control unit 7 carries out grinding using the grinding wheel 77 until the thickness of the wafer 100 reaches a predetermined thickness that has been set in advance. Note that this grinding causes the wafer ID formed on the back surface 102 of the wafer 100 to disappear.

[0073] [Cleaning process] After the grinding process, the control unit 7 controls the unloading mechanism 172 to hold the wafer 100 held on the chuck table 20 and place it on the spinner table 157 of the spinner cleaning mechanism 156. Then, the control unit 7 cleans the wafer 100 using the spinner cleaning mechanism 156.

[0074] [Wafer ID restoration process] After the cleaning process, the control unit 7 uses the robot 155 to remove the cleaned wafer 100 from the spinner cleaning mechanism 156, place it on the temporary placement table 154 of the temporary placement mechanism 152 again with the back surface 102 facing upward, and align the wafer 100 to a predetermined position.

[0075] Thereafter, the control unit 7 controls the rotation mechanism 151 of the temporary placement mechanism 152, as well as the X-axis direction moving mechanism 120 (see Figure 2) and the Y-axis direction moving mechanism 140 (see Figure 3) in the ID forming unit 110, to position the processing head 136 of the laser processing unit 135 directly above the wafer ID formation position on the back surface 102 of the wafer 100 placed on the temporary placement table 154.

[0076] Next, the control unit 7 reads out the wafer ID formed on the back surface 102 of the wafer 100 from the storage unit 8. Then, based on the notation of the read-out wafer ID, the control unit 7 adjusts the position of the processing head 136 using the X-axis direction moving mechanism 120 and the Y-axis direction moving mechanism 140, thereby moving the irradiation position of the laser beam 300 applied from the processing head 136 to the back surface 102 of the wafer 100 in accordance with the notation of the wafer ID. In this way, the control unit 7 can restore the wafer ID to the back surface 102 of the wafer 100 by the laser beam 300 from the processing head 136.

[0077] Thereafter, the control unit 7 causes the robot 155 to remove the wafer 100 from the temporary placement table 154 and carry it into the second cassette 163 on the second cassette stage 162.

[0078] As described above, in this embodiment, the grinding apparatus 1 includes the ID forming unit 110 that reads and restores the wafer ID. The reading unit 130 reads the wafer ID of the unground wafer 100 placed on the temporary placement table 154 by the robot 155. Furthermore, the laser processing unit 135 restores the wafer ID to the ground wafer 100 placed on the temporary placement table 154 by the robot 155.

[0079] As described above, in this embodiment, the existing components of the robot 155 and temporary placement table 154 are used to perform reading and restoration processing by the ID forming unit 110. Therefore, the components added for restoring the wafer ID can be reduced, and the wafer ID can be restored within the grinding apparatus 1 without increasing the size of the grinding apparatus 1.

[0080] In the embodiment described above, the reading unit 130 reads the wafer ID of the wafer 100 temporarily placed on the temporary placement table 154 in the wafer ID reading step. In this regard, the reading unit 130 may read the wafer ID of the wafer 100 removed from the first cassette 161 and held by the robot 155 .

[0081] In this case, the control unit 7 positions the wafer 100 held by the holding member 150 of the robot 155 above the temporary placement table 154 and below the first camera 131 of the reading unit 130 in the ID formation unit 110, with the back surface 102 facing upward.

[0082] Then, the control unit 7 controls the X-axis direction moving mechanism 120 and the Y-axis direction moving mechanism 140 of the ID forming unit 110, and the robot 155, to position the first camera 131 of the reading unit 130 directly above the wafer ID formed on the back surface 102 of the wafer 100 held by the robot 155. The reading unit 130 then reads the wafer ID of the wafer 100 using the first camera 131, and stores it in the memory unit 8.

[0083] Alternatively, the reading unit 130 may read the wafer ID of the wafer 100 held by the loading mechanism 170 . In this case, after aligning the wafer 100 in the temporary placement mechanism 152, the control unit 7 suction-holds the wafer 100 using the suction pad 171 of the carry-in mechanism 170. Then, the control unit 7 positions the wafer 100 held by the suction pad 171 below the first camera 131 of the reading unit 130 in the ID formation unit 110.

[0084] Then, the control unit 7 controls the X-axis direction moving mechanism 120 and the Y-axis direction moving mechanism 140 of the ID forming unit 110, and the carry-in mechanism 170, to position the first camera 131 of the reading unit 130 directly above the wafer ID formed on the back surface 102 of the wafer 100 held by the carry-in mechanism 170. The reading unit 130 then reads the wafer ID of the wafer 100 using the first camera 131, and stores it in the memory unit 8.

[0085] In the above-described embodiment, the reading unit 130 that reads the wafer ID of the wafer 100 is provided in the ID forming unit 110 that is provided on the +Y direction side of the temporary placement mechanism 152. In this regard, the reading unit 130 may be disposed near the chuck table 20 so as to be able to read the wafer ID of the wafer 100 held on the holding surface 22 of the chuck table 20. In this case, the reading unit 130 reads the wafer ID of the wafer 100 before the wafer 100 held on the chuck table 20 is ground by the grinding wheel 77.

[0086] In the above-described embodiment, the laser processing unit 135 for restoring the wafer ID to the back surface 102 of the wafer 100 is provided in the ID forming unit 110 provided on the +Y direction side of the temporary placement mechanism 152. In this regard, the laser processing unit 135 may be disposed in the spinner cleaning mechanism 156.

[0087] In this case, after the cleaning step, the control unit 7 restores the wafer ID to the back surface 102 of the wafer 100 held on the spinner table 157 by using the laser beam 300. Then, the control unit 7 cleans the wafer 100 again after the wafer ID has been restored in the spinner cleaning mechanism 156. The wafer ID may be restored to the wafer 100 held by the holding member 150 of the robot 155 or the wafer 100 held by the suction pad 173 of the carry-out mechanism 172. In the above, the outer periphery of the wafer 100, on which the wafer ID is to be restored, protrudes from the holding member 150 or the suction pad 173.

[0088] Thereafter, the control unit 7 causes the robot 155 to remove the cleaned wafer 100 from the spinner cleaning mechanism 156 and transfer it into the second cassette 163 on the second cassette stage 162.

[0089] In this configuration, the wafer 100 after the wafer ID has been restored can be easily cleaned by the spinner cleaning mechanism 156. Therefore, it is possible to effectively remove processing debris from the wafer 100 that is generated when the wafer ID is restored using the laser beam 300.

[0090] The ID forming unit 110 including the reading unit 130 and the laser processing unit 135 may be disposed near the spinner cleaning mechanism 156 .

[0091] In this case, in the wafer ID reading step, the control unit 7 causes the robot 155 to take out the unprocessed wafer 100 from the first cassette 161 and place it on the spinner table 157 of the spinner cleaning mechanism 156 with the back surface 102 facing upward. Thereafter, the control unit 7 causes the reading unit 130 of the ID forming unit 110 to read the wafer ID of the wafer 100 on the spinner table 157, and then causes the robot 155 to transport the wafer 100 to the temporary placement mechanism 152, where the holding step, grinding step, and cleaning step described above are performed.

[0092] After the cleaning process, the control unit 7 restores the wafer ID to the back surface 102 of the wafer 100 supported on the spinner table 157 using the laser processing unit 135, and then performs cleaning again. Even with this configuration, it is possible to effectively remove from the wafer 100 processing debris generated when restoring the wafer ID.

[0093] 6, the laser processing unit 135 may have an optical system using a galvanometer mirror. In this case, the laser processing unit 135 includes an oscillator 201 that oscillates a laser beam 301, an X-axis galvanometer mirror section 205 and a Y-axis galvanometer mirror section 210 that deflect the laser beam 301, a direction-changing mirror 215 that changes the direction of the laser beam 301, and an fθ lens 217.

[0094] In this configuration, for example, the oscillator 201, the X-axis galvanometer mirror section 205, and the Y-axis galvanometer mirror section 210 are arranged in the laser housing section 137 of the laser processing unit 135 shown in Figure 3, and the direction conversion mirror 215 and the fθ lens 217 are arranged in the processing head 136 of the laser processing unit 135.

[0095] X-axis galvanometer mirror section 205 includes X-axis mirror 206 and X-axis actuator 207 that adjusts the rotation angle of X-axis mirror 206. In X-axis galvanometer mirror section 205, the rotation angle of X-axis mirror 206 is adjusted by X-axis actuator 207, thereby deflecting the optical axis of laser beam 301 from oscillator 201 in the X-axis direction.

[0096] Y-axis galvanometer mirror section 210 includes Y-axis mirror 211 and Y-axis actuator 212 that adjusts the rotation angle of Y-axis mirror 211. In Y-axis galvanometer mirror section 210, the rotation angle of Y-axis mirror 211 is adjusted by Y-axis actuator 212, thereby deflecting the optical axis of laser beam 301 from X-axis galvanometer mirror section 205 in the Y-axis direction.

[0097] The direction-changing mirror 215 changes the direction of the laser beam 301 deflected by the X-axis galvanometer mirror section 205 and the Y-axis galvanometer mirror section 210 downward. The fθ lens 217 converts the laser beam 301 deflected by the X-axis galvanometer mirror section 205 and the Y-axis galvanometer mirror section 210 into parallel beams of equal condensed height, and irradiates the rear surface 102 of the wafer 100 substantially perpendicularly.

[0098] In the laser processing unit 135 having such a configuration, by adjusting the rotation angles of the X-axis mirror 206 and the Y-axis mirror 211 and thereby adjusting the deflection state of the laser beam 301 reflected by them, the laser beam 301 can be irradiated to any position on the back surface 102 of the wafer 100 located below the fθ lens 217.

[0099] When using a laser processing unit 135 configured in this manner, the control unit 7 controls the rotation mechanism 151 of the temporary placement mechanism 152, as well as the X-axis direction movement mechanism 120 (see Figure 2) and the Y-axis direction movement mechanism 140 (see Figure 3) in the ID formation unit 110 during the wafer ID restoration process, to position the processing head 136 of the laser processing unit 135 directly above the wafer ID formation position on the back surface 102 of the wafer 100 placed on the temporary placement table 154.

[0100] Then, the control unit 7 reads out the wafer ID formed on the back surface 102 of the wafer 100 from the storage unit 8, and adjusts the rotation angles of the X-axis mirror 206 and the Y-axis mirror 211 using the X-axis actuator 207 and the Y-axis actuator 212 based on the notation of this wafer ID, thereby moving the irradiation position of the laser beam 301 irradiated from the processing head 136 onto the back surface 102 of the wafer 100 in accordance with the notation of the wafer ID. In this way, the control unit 7 can restore the wafer ID on the back surface 102 of the wafer 100 by the laser beam 301. The laser processing unit 135 may be fixedly disposed above the temporary placement table 154, and the wafer ID may be restored simply by adjusting the rotation angles of the X-axis mirror 206 and the Y-axis mirror 211. Furthermore, when restoring the wafer ID using the laser processing unit 135 arranged above the spinner table 157, the spinner table 157 may be continuously rotated and the rotation angle of the spinner table 157 may be recognized by an encoder to restore the wafer ID. Furthermore, as described above, water may be supplied to the top surface of the continuously rotated wafer 100 to form a water layer to restore the wafer ID and prevent contamination caused by laser processing from adhering to the wafer 100. The laser processing unit 135 may be disposed above the chuck table 20.

[0101] In addition, this embodiment shows an example of grinding a circular wafer 100. In this regard, the shape of the wafer in this embodiment is not limited to a circle, and may be a polygon such as a square.

[0102] In this embodiment, the back surface 102 of the wafer 100 placed on the temporary placement table 154 of the temporary placement mechanism 152 is imaged by the first camera 131 of the reading unit 130, and the wafer ID formed on the back surface 102 is read. In this regard, the second camera 187 of the laser processing unit 135 shown in FIG. 4 may be used to read the wafer ID on the back surface 102 of the wafer 100. This second camera 187 can image the back surface 102 of the wafer 100 placed on the temporary placement table 154 via the dichroic mirror 184 and the condenser 182. [Explanation of symbols]

[0103] 1: grinding device, 7: control unit, 8: memory unit, 10: first device base, 11: second device base, 12: bellows cover, 13: opening, 15: column, 20: chuck table, 21: porous member, 22: holding surface, 23: frame body, 24: Frame surface, 39: Cover plate, 60: Grinding feed mechanism, 61: Z-axis guide rail, 62: Z-axis ball screw, 63: Z-axis moving table, 64: Z-axis motor, 65: Z-axis encoder, 66: holder, 70: grinding mechanism, 71: spindle housing, 72: Spindle, 73: Spindle motor, 74: Wheel mount, 75: Grinding wheel, 76: Wheel base, 77: Grinding stone, 80: Thickness measuring instrument, 81: Holding surface height gauge, 82: Upper surface height gauge, 100: Wafer, 101: front surface, 102: back surface, 110: ID forming unit, 111: portal column, 112: Housing, 120: X-axis direction movement mechanism, 121: X-axis guide rail, 122: X-axis ball screw, 123: X-axis moving table, 124: X-axis motor, 125: X-axis encoder, 130: reading unit, 131: first camera, 132: lighting; 133: camera housing; 134: first opening; 135: laser processing unit, 136: processing head, 137: laser housing part, 138: second opening part, 139: tip part, 140: Y-axis direction movement mechanism, 141: Y-axis guide rail, 142: Y-axis ball screw, 143: Y-axis moving table, 144: Y-axis motor, 145: Y-axis encoder, 146: holder, 150: holder member, 151: rotation mechanism, 152: temporary placement mechanism, 153: alignment member, 154: temporary placement table, 155: robot, 156: spinner cleaning mechanism, 157: spinner table, 158: nozzle, 160: first cassette stage, 161: first cassette, 162: second cassette stage, 163: second cassette, 170: loading mechanism, 171: suction pad, 172: unloading mechanism, 173: suction pad, 180: laser oscillator, 182: condenser, 184: dichroic mirror, 186: lifting mechanism, 187: second camera, 191: fluid injection nozzle, 192: fluid source, 193: fluid recovery nozzle, 194: suction source, 201: oscillator, 205: X-axis galvanometer mirror section, 206: X-axis mirror, 207: X-axis actuator, 210: Y-axis galvanometer mirror section, 211: Y-axis mirror, 212: Y-axis actuator, 215: direction-changing mirror, 217: fθ lens, 300: laser beam, 301: Laser beam, 310: Processing point

Claims

1. A grinding device including a chuck table that holds a front surface side of a wafer having a wafer ID formed on a back surface thereof, and a grinding mechanism that grinds the back surface of the wafer held by the chuck table with a grinding wheel, a reading unit that reads the wafer ID before the chuck table holds the wafer or before the wafer held on the chuck table is ground; a laser processing unit that restores the wafer ID read by the reading unit on the back surface of the ground wafer, The laser processing unit includes: a fluid injection nozzle that injects a fluid toward a processing point, which is a portion on the back surface of the wafer that is irradiated with a laser beam; a fluid recovery nozzle that sucks fluid from the vicinity of the processing point, Grinding equipment.

2. a cassette stage for placing a cassette containing wafers in a shelf-like manner, a robot for removing wafers from the cassette on the cassette stage, and a loading mechanism for transporting the wafer removed by the robot to the chuck table, the reading unit reads the wafer ID of the wafer held by the robot or the wafer held by the loading mechanism; The grinding device according to claim 1.

3. a temporary placement table for temporarily placing a wafer; the reading unit reads the wafer ID of the wafer temporarily placed on the temporary placement table; The grinding device according to claim 1.

4. a spinner cleaning mechanism for cleaning the wafer ground by the grinding mechanism; the laser processing unit is disposed in the spinner cleaning mechanism; The grinding device according to claim 1.

Images