Processing device

Abstract

To reduce a time for separating a wafer from a holding surface of a chuck table.SOLUTION: A processing device reduces a flow rate of air to be supplied to a holding surface 22 (a communication passage 470) with an air adjustment part 483 to allow only air to reach the holding surface 22 through the communication passage 470 while leaving processing water in the communication passage 470 when a wafer 100 is separated from the holding surface 22 by supplying air to the holding surface 22. Thus, compared to a configuration in which both of air and processing water reach the holding surface 22, a time from opening of a first air supply valve 485 to a time at which air reaches the holding surface 22 can be reduced. Therefore, a time for separating the wafer 100 from the holding surface 22 can be reduced.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] As disclosed in Patent Document 1, a grinding device for grinding a plate-shaped workpiece jets a mixed fluid of water and air from the chuck table when removing the ground plate-shaped workpiece from the chuck table.

[0003] The chuck table includes a porous plate, a frame having a recess for accommodating the porous plate, and a suction hole opening at the bottom of the recess. The suction hole is connected to a communication passage disposed in a support unit that supports the chuck table, and the communication passage is connected to a suction source. Therefore, during the grinding process, the communication passage, the suction hole, and the porous plate are under negative pressure. After the grinding process is completed, a mixed fluid is supplied to the communication passage, the suction hole, and the porous plate, and the mixed fluid is sprayed from the holding surface to separate the plate-shaped workpiece from the holding surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-184269 [Patent Document 2] Japanese Patent Publication No. 2020-145256 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-described configuration, the fluid mixture is filled into the communication passages, suction holes, and porous plate, and then ejected from the holding surface, which means that it takes time to release the plate-shaped workpiece from the holding surface.

[0006] Therefore, an object of the present invention is to shorten the time required to separate a plate-shaped workpiece from the holding surface of a chuck table in a processing apparatus such as a grinding apparatus that grinds a plate-shaped workpiece. [Means for solving the problem]

[0007] The processing device of the present invention (the present processing device) is a processing device comprising a chuck table that suction-holds a plate-shaped workpiece with a holding surface, and a processing mechanism that processes the plate-shaped workpiece held on the chuck table while supplying processing water to the plate-shaped workpiece, wherein the chuck table comprises a porous plate having the holding surface on its upper surface, and a frame body having a recess that accommodates the porous plate so that the holding surface is exposed, a communication passage that opens at the bottom of the recess and is connected to the holding surface, a suction passage that is connected to the communication passage and connects the holding surface to a suction source, and a suction passage that is disposed in the suction passage and is opened and closed to switch the communication state between the holding surface and the suction source. The apparatus comprises a suction valve, an air supply passage connected to the communication passage and connecting the holding surface with an air source, an air supply valve disposed in the air supply passage and opening and closing to switch the communication state between the holding surface and the air source, and a throttle valve that sets the flow rate of air sent from the air source to the holding surface when the air supply valve is open, and the throttle valve is configured to set the flow rate of air supplied to the holding surface so that, when the suction valve is closed and the air supply valve is opened to connect the air source to the holding surface and supply air to the holding surface, machining water remains in the communication passage and only air is supplied to the holding surface.

[0008] The processing apparatus may further include a conveying pad having a suction surface that holds the upper surface of the plate-shaped workpiece by suction, and a lifting mechanism that raises and lowers the conveying pad, and the lifting mechanism may be configured to raise the conveying pad that holds the plate-shaped workpiece on the holding surface by suction after a predetermined time has elapsed since the air supply valve was opened, and to separate the plate-shaped workpiece from the holding surface. [Effects of the Invention]

[0009] In this machining device, when air is supplied to the holding surface to release the plate-shaped workpiece from the holding surface, the flow rate of air supplied to the holding surface is throttled using a throttle valve, preventing the machining water in the communicating passage from being pushed up toward the holding surface by the air. This allows only the air to reach the holding surface through the communicating passage, while leaving the machining water in the communicating passage. Therefore, compared to a configuration in which both air and machining water reach the holding surface, the time from when the air supply valve is opened until the air reaches the holding surface can be shortened. This makes it possible to shorten the time required to release the plate-shaped workpiece from the holding surface.

[0010] In addition, since the processing water is prevented from spraying out from the holding surface, it is possible to prevent the underside of the plate-shaped workpiece from being soiled by processing water containing processing debris, thereby eliminating the need for a cleaning unit to clean the underside of the plate-shaped workpiece. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view showing the configuration of a grinding device. [Figure 2] FIG. 2 is a partial cross-sectional view showing the configuration of a carry-out mechanism and a chuck table. [Figure 3] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] As shown in FIG. 1, a grinding apparatus 1 according to this embodiment is an example of a processing apparatus, and is an apparatus for grinding a wafer 100. The wafer 100 is an example of a plate-like workpiece, and has a roughly circular disk shape. The wafer 100 is made of a semiconductor material such as silicon. A back surface 102 of the wafer 100 is the surface to be ground. A protective tape, for example, is attached to a front surface 101 of the wafer 100.

[0013] The grinding device 1 includes a first device base 11, a second device base 12 connected to the rear (+Y direction side) of the first device base 11, and a column 13 extending upward.

[0014] A first cassette stage 151 and a second cassette stage 152 are provided on the front side (-Y direction side) of the first apparatus base 11. A first cassette 153 and a second cassette 154, which store wafers 100, are placed on the first cassette stage 151 and the second cassette stage 152, respectively.

[0015] The first cassette 153 and the second cassette 154 each have a plurality of shelves therein, and each shelf accommodates one wafer 100 .

[0016] The openings (not shown) of the first cassette 153 and the second cassette 154 face the +Y direction side. The grinding apparatus 1 is provided with a robot 155 on the +Y direction side of these openings, which moves the wafers 100 in and out of the first cassette 153 and the second cassette 154. The robot 155 carries the processed wafers 100 into the first cassette 153 or the second cassette 154. The robot 155 also takes out the unprocessed wafers 100 from the first cassette 153 or the second cassette 154 and places them on the temporary placement table 142 of the temporary placement mechanism 140.

[0017] The temporary placement mechanism 140 is used to temporarily place the wafer 100 taken out from the first cassette 153 or the second cassette 154, and is provided at a position adjacent to the robot 155. The temporary placement mechanism 140 has a temporary placement table 142 and an alignment member 141. The alignment member 141 has a plurality of alignment pins arranged on the outside so as to surround the temporary placement table 142, and a slider that moves the alignment pins in the radial direction of the temporary placement table 142. In the alignment member 141, the alignment pins are moved toward the center in the radial direction of the temporary placement table 142, 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 142 is aligned (centered) at a predetermined position where the center of the temporary placement table 142 and the center of the wafer 100 coincide with each other.

[0018] A carry-in mechanism 170 is provided at a position adjacent to the temporary placement mechanism 140. The carry-in mechanism 170 holds the wafer 100 temporarily placed on the temporary placement mechanism 140, and carries it in and places it on the holding surface 22 of the chuck table 20.

[0019] An opening 14 is provided on the upper surface side of the second device base 12. A chuck table 20 is disposed within the opening 14.

[0020] The chuck table 20 holds the wafer 100 by means of a holding surface 22 so that a back surface 102, which is the surface to be processed of the wafer 100, is exposed. The holding surface 22 is connected to a first suction source 47 (see FIG. 2 ) and is capable of suction-holding the front surface 101 side of the wafer 100. In other words, the chuck table 20 is configured to suction-hold the wafer 100 by means of the holding surface 22. Furthermore, while the chuck table 20 holds the wafer 100 by means of the holding surface 22, the chuck table 20 is rotatable about a rotation axis that passes through the center of the holding surface 22 and extends in the Z-axis direction.

[0021] The periphery of the chuck table 20 is surrounded by a cover 16. A bellows cover 15 that expands and contracts in the Y-axis direction is connected to this cover 16. A Y-axis direction movement mechanism (not shown) is disposed below the cover 16 and the bellows cover 15. The Y-axis direction movement mechanism enables the chuck table 20 to move back and forth in the Y-axis direction.

[0022] In this embodiment, the chuck table 20 moves between a wafer holding position on the -Y direction side for placing the wafer 100 on the holding surface 22 and a grinding position on the +Y direction side for grinding the wafer 100.

[0023] A column 13 is erected at the rear (+Y direction side) of the second device base 12. A grinding mechanism 3 that grinds the wafers 100 and a grinding feed mechanism 4 that moves the grinding mechanism 3 in the Z-axis direction, which is the grinding feed direction, are provided in front of the column 13.

[0024] The grinding feed mechanism 4 includes a pair of Z-axis guide rails 41 parallel to the Z-axis direction, a Z-axis moving table 43 that slides on the Z-axis guide rails 41, a Z-axis ball screw 40 parallel to the Z-axis guide rails 41, a Z-axis motor 42, and a holder 44 attached to the Z-axis moving table 43. The holder 44 holds the grinding mechanism 3.

[0025] Z-axis moving table 43 is slidably installed on Z-axis guide rail 41. A nut portion (not shown) is fixed to Z-axis moving table 43. Z-axis ball screw 40 is threadedly engaged with this nut portion. Z-axis motor 42 is connected to one end of Z-axis ball screw 40.

[0026] In the grinding feed mechanism 4, the Z-axis motor 42 rotates the Z-axis ball screw 40, causing the Z-axis moving table 43 to move in the Z-axis direction along the Z-axis guide rail 41. As a result, the holder 44 attached to the Z-axis moving table 43 and the grinding mechanism 3 held by the holder 44 move in the Z-axis direction together with the Z-axis moving table 43.

[0027] The grinding mechanism 3 is an example of a processing mechanism, and processes the wafer 100 while supplying processing water to the wafer 100 held on the chuck table 20. The grinding mechanism 3 includes a spindle housing 31 fixed to a holder 44, a spindle 30 rotatably held in the spindle housing 31, a motor 32 that rotates and drives the spindle 30, a wheel mount 33 attached to the lower end of the spindle 30, and a grinding wheel 34 supported by the wheel mount 33.

[0028] The spindle housing 31 is held by the holder 44 so as to extend in the Z-axis direction. The spindle 30 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 31.

[0029] The motor 32 is connected to the upper end side of the spindle 30. The motor 32 causes the spindle 30 to rotate about a rotation axis extending in the Z-axis direction.

[0030] The wheel mount 33 is formed in a disk shape and is fixed to the lower end (tip) of the spindle 30. The wheel mount 33 supports the grinding wheel .

[0031] The grinding wheel 34 is formed to have approximately the same diameter as the wheel mount 33. The grinding wheel 34 includes an annular wheel base 35. A plurality of grinding stones 36 are fixed to the underside of the wheel base 35, arranged in an annular shape around the entire circumference. The grinding stones 36 grind the back surface 102 of the wafer 100 held on the chuck table 20.

[0032] In addition, in the grinding mechanism 3, during grinding processing, processing water (grinding water) from the grinding water supply source 17 is supplied to the wafer 100 (the contact point between the wafer 100 and the grinding wheel 36) via a flow path provided in the spindle 30, for example.

[0033] A thickness measuring device 38 is disposed at a position adjacent to the chuck table 20. The thickness measuring device 38 can measure the thickness of the wafer 100 during grinding, for example, by contact.

[0034] The ground wafer 100 is carried out by the carry-out mechanism 172. The carry-out mechanism 172 holds the wafer 100 held on the holding surface 22 of the chuck table 20 and carries it out from the holding surface 22. The carry-out mechanism 172 transports the wafer 100 carried out from the holding surface 22 to a spinner table 157 of a single-wafer type spinner cleaning mechanism 156.

[0035] The spinner cleaning mechanism 156 is a spinner cleaning unit that cleans the wafer 100. 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.

[0036] 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.

[0037] The wafer 100 cleaned by the spinner cleaning mechanism 156 is carried by the robot 155 into the first cassette 153 or the second cassette 154 (for example, the cassette from which the wafer 100 was removed).

[0038] Here, the configuration of the chuck table 20 will be described. As shown in FIG. 2, the chuck table 20 is a circular, plate-shaped table for holding the wafer 100. The chuck table 20 includes a porous plate 21 having a holding surface 22 on its upper surface, and a frame 23 having a recess 231 for accommodating the porous plate 21. The upper surface of the porous plate 21 is the holding surface 22 that suction-holds the wafer 100. The holding surface 22 is connected to a first suction source 47, thereby suction-holding the wafer 100. The frame 23 accommodates the porous plate 21 in the recess 231 so that the holding surface 22 is exposed.

[0039] A rotation mechanism 25 for rotating the chuck table 20 is connected to the bottom surface of the frame 23. The rotation mechanism 25 rotates the chuck table 20 about a rotation axis that passes through the center of the holding surface 22 and is perpendicular to the holding surface 22.

[0040] A fluid distribution mechanism 46 is connected to the chuck table 20. The fluid distribution mechanism 46 is a mechanism for supplying a fluid such as air, water, or a mixture of air and water to the holding surface 22 of the chuck table 20, or for applying a suction force to the holding surface 22.

[0041] The fluid circulation mechanism 46 includes a communication passage 470 that penetrates the center of the frame 23 and is connected to the bottom surface of the porous plate 21 , and a suction passage 471 that is connected to the communication passage 470 .

[0042] The lower end of the communicating passage 470 extends below the frame 23. On the other hand, the upper end of the communicating passage 470 opens at the bottom (for example, at the center of the bottom) of the recess 231 of the frame 23, and is connected to the bottom surface of the porous plate 21. Therefore, the communicating passage 470 is connected to the holding surface 22 on the upper surface thereof via the porous plate 21. In other words, the communicating passage 470 opens at the bottom of the recess 231 and is connected to the holding surface 22. In addition, the communicating passage 470 is provided with a measuring device 440 for measuring the flow rate and / or pressure within the communicating passage 470.

[0043] A suction path 471 is connected to the lower end of the communication path 470. The suction path 471 is a pipe for communicating between the holding surface 22 of the chuck table 20 and the first suction source 47. One end of the suction path 471 is connected to the lower end of the communication path 470. The other end of the suction path 471 is connected to the first suction source 47. In other words, the suction path 471 is connected to the communication path 470, and together with the communication path 470, connects the holding surface 22 and the first suction source 47.

[0044] The first suction source 47 includes a vacuum generating device such as a vacuum pump or an ejector mechanism, and is connected to the porous plate 21 of the chuck table 20 to apply suction force to the holding surface 22, which is the upper surface thereof.

[0045] In addition, a first suction valve 475 and a suction flow rate adjuster 473 are disposed in the suction path 471 in this order from the first suction source 47 toward the communication path 470. The first suction valve 475 switches the communication state between the holding surface 22 and the first suction source 47 by opening and closing. The suction flow rate adjustment unit 473 is, for example, a proportional control valve, and is used to change the internal orifice diameter when the first suction valve 475 is open, thereby adjusting the suction force transmitted from the first suction source 47 to the holding surface 22 of the porous plate 21.

[0046] Furthermore, in addition to the suction path 471, an air supply path 481 is also connected to the lower end of the communication path 470. The air supply path 481 is a pipe for communicating between the holding surface 22 of the chuck table 20 and the first air source 48.

[0047] One end of the air supply path 481 is connected to the lower end of the communication path 470. The other end of the air supply path 481 is connected to the first air source 48. In other words, the air supply path 481 is connected to the communication path 470, and together with the communication path 470, connects the holding surface 22 and the first air source 48. The first air source 48 includes a compressor or the like and is used to supply air to the holding surface 22 of the chuck table 20 .

[0048] In addition, a first air supply valve 485 and an air adjustment unit 483 are disposed in the air supply path 481 in this order from the first air source 48 toward the communication path 470. The first air supply valve 485 switches the communication state between the holding surface 22 and the first air source 48 by opening and closing.

[0049] The air adjusting unit 483 is an example of a throttle valve. The air adjusting unit 483 is used to set (adjust) the flow rate of air sent from the first air source 48 to the holding surface 22 when the first air supply valve 485 is open. The air adjusting unit 483 is, for example, a proportional control valve, and can adjust the flow rate of air sent from the first air source 48 to the holding surface 22 by changing the diameter of an orifice inside.

[0050] A water supply path 491 is connected to the air supply path 481. The water supply path 491 is a pipe that connects the holding surface 22 of the chuck table 20 and the first water supply source 49.

[0051] One end of the water supply passage 491 is connected to the communication passage 470 via the air supply passage 481. The other end of the water supply passage 491 is connected to the first water supply source 49. In other words, the water supply passage 491 is connected to the air supply passage 481 and the communication passage 470, and connects the holding surface 22 and the first water supply source 49 together with the air supply passage 481 and the communication passage 470. The first water supply source 49 includes a pump or the like and is used to supply water to the holding surface 22 of the chuck table 20 .

[0052] In addition, a water supply valve 495 and a water adjustment unit 493 are arranged in the water supply path 491 in this order from the first water supply source 49 toward the communication path 470. The water supply valve 495 switches the communication state between the holding surface 22 (water supply path 491) and the first water supply source 49 by opening and closing.

[0053] The water adjusting unit 493 is, for example, a proportional control valve, and is used to change the internal orifice diameter to adjust the flow rate of water sent from the first water supply source 49 to the holding surface 22 when the water supply valve 495 is open.

[0054] The suction flow rate adjusting unit 473, the air adjusting unit 483, and the water adjusting unit 493 may be needle valves or gate valves whose orifice diameters are manually adjusted.

[0055] Next, a description will be given of the configuration of the unloading mechanism 172. The unloading mechanism 172 is an example of a transfer device that transfers the wafer 100, and uses a transfer pad 80 to unload the wafer 100 from the chuck table 20.

[0056] 2, the carry-out mechanism 172 includes a disk-shaped transport pad 80, an arm 81 that suspends the transport pad 80 so that it can move up and down freely, a rotating column 82 that extends in the Z-axis direction, and a movement mechanism 50 that is connected to the rotating column 82. The base end of the arm 81 is connected to the upper end of the rotating column 82. The movement mechanism 50 moves the rotating column 82 together with the arm 81 and transport pad 80.

[0057] The moving mechanism 50 is a mechanism for moving the transport pad 80. The moving mechanism 50 includes a column 51 erected on the first device base 10 (see FIG. 1 ), a guide rail 53 attached to the column 51, a ball screw 52 disposed parallel to the guide rail 53, a motor 54 for rotating the ball screw 52, ​​an encoder 57 for detecting the amount of rotation of the ball screw 52 (for example, the number of rotations and the rotation angle), and a nut 55 threaded onto the ball screw 52. A rotating column 82 is slidably installed on the guide rail 53. The rotating column 82 is connected to the nut 55.

[0058] In the movement mechanism 50, the motor 54 rotates the ball screw 52 about a rotation shaft extending in the Z-axis direction, thereby moving the rotating column 82 up and down in the Z-axis direction along the guide rail 53. By moving the rotating column 82 up and down in the Z-axis direction in this manner, the arm 81 connected to the rotating column 82 and the transport pad 80 suspended by the arm 81 are moved up and down.

[0059] In this way, the movement mechanism 50 functions as an elevation mechanism that raises and lowers the transport pad 80. When the transport pad 80 is raised and lowered, the encoder 57 recognizes the amount of rotation of the ball screw 52, ​​and based on the recognition result, detects the height position of the transport pad 80 that is raised and lowered in the Z-axis direction.

[0060] Furthermore, the movement mechanism 50 is configured to be able to rotate the arm 81 about a rotation axis 821 that passes through the rotating column 82 and extends in the Z-axis direction. In this embodiment, the arm 81 can be rotated together with the suspended transport pad 80 about the rotation axis 821 by a rotation motor (not shown).

[0061] In this way, the movement mechanism 50 moves the carrying pad 80 by moving the arm 81 up and down and by rotating the arm 81, and can adjust the height and horizontal position of the carrying pad 80.

[0062] A disk member 84 is connected to the other end (tip) of arm 81 via a plurality (e.g., three) of support posts 83. A plurality (e.g., three) of through holes 85 are formed through disk member 84 at equal intervals on the circumference. A bolt 86 connected to transport pad 80 is inserted into each of the through holes 85.

[0063] The bolt 86 has a shaft portion 87 having a diameter slightly smaller than that of the through-hole 85 and a head portion 88 formed at the upper end of the shaft portion 87 . The shaft 87 is loosely fitted through the through-hole 85. The lower end of the shaft 87 is connected to the upper surface of the frame 91 of the transport pad 80. The head 88 has a diameter larger than the through-hole 85, and limits the downward range of the bolt 86. The bolt 86 may have a spring (not shown) around the shaft portion 87 as a shock absorbing member that urges the disk member 84 and the transport pad 80 in directions away from each other.

[0064] The arm 81 is capable of suspending the transport pad 80 while absorbing impacts applied to the transport pad 80 via the disk member 84 and bolt 86 configured as described above.

[0065] The disk-shaped transfer pad 80 has an area slightly larger than that of the wafer 100, for example, and includes a pad holding portion 90 made of a porous material and a frame 91 that supports the pad holding portion 90. The lower surface of the pad holding portion 90 serves as a suction surface 92 that suction-holds the back surface 102, which is the upper surface of the wafer 100. In other words, the transfer pad 80 has the suction surface 92 that suction-holds the upper surface of the wafer 100.

[0066] The carry-out mechanism 172 also includes a fluid path 89. The fluid path 89 extends through a through-hole 841 provided in the center of the disc member 84 and the frame body 91 of the transport pad 80, and its lower end is connected to the upper surface of the pad holding part 90. The upper end of the fluid path 89 is connected to a second air source 97 via a second air supply valve 96, and is also connected to a second suction source 99 via a second suction valve 98.

[0067] Therefore, in the unloading mechanism 172, when the suction surface 92 is in contact with the wafer 100 held on the holding surface 22 of the chuck table 20, the second suction source 99 is connected to the fluid path 89, so that the suction force of the second suction source 99 is transmitted to the suction surface 92, making it possible for the suction surface 92 to hold the wafer 100 by suction.

[0068] Then, by using the moving mechanism 50 to rotate and raise and lower the rotating column 82 and the arm 81, the transport pad 80 holding the wafer 100 can be rotated and raised and lowered, and the wafer 100 can be removed from the chuck table 20.

[0069] Furthermore, when the wafer 100 is held on the suction surface 92, the communication between the second suction source 99 and the fluid path 89 can be blocked and the second air source 97 can be connected to the fluid path 89, thereby spraying air from the suction surface 92 and separating the wafer 100 from the suction surface 92. The carry-in mechanism 170 shown in FIG. 1 may have the same configuration as the carry-out mechanism 172.

[0070] 1, the grinding apparatus 1 has therein 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.

[0071] 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. The grinding process by the grinding device 1 controlled by the control unit 7 will be described below, focusing on the unloading step of unloading the ground wafer 100 from the chuck table 20.

[0072] [Holding process] In the grinding process, a holding step is first performed. In this step, the control unit 7 controls the robot 155 shown in Fig. 1 to take out the unprocessed wafer 100 from the first cassette 153 or the second cassette 154, place it on the temporary placement table 142 of the temporary placement mechanism 140, and align the wafer 100 at a predetermined position.

[0073] Furthermore, the control unit 7 controls the carry-in mechanism 170 to hold the wafer 100 on the temporary placement table 142 and place the wafer 100 with the back surface 102 facing up on the holding surface 22 of the chuck table 20 located at the wafer holding position on the -Y direction side. Thereafter, the control unit 7 places the chuck table 20 at the grinding position on the +Y direction side below the grinding mechanism 3.

[0074] [Grinding process] After the holding step, the grinding step is performed. In this step, the control unit 7 rotates the grinding wheel 34 of the grinding mechanism 3 shown in FIG. 1 and also rotates the chuck table 20. Then, the control unit 7 causes the grinding mechanism 3, including the grinding wheel 34, to be fed in the -Z direction by the grinding feed mechanism 4. As a result, the grinding stone 36 of the rotating grinding wheel 34 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. At this time, processing water supplied from the grinding water supply source 17 is supplied to the contact point between the wafer 100 and the grinding stone 36.

[0075] Furthermore, in the grinding process, the control unit 7 measures the thickness of the wafer 100 during grinding using the thickness measuring device 38. Then, the control unit 7 ends grinding of the wafer 100 when the thickness of the wafer 100 reaches a predetermined thickness.

[0076] [Export process] After the grinding process, the unloading process is carried out, and the unloading mechanism 172 unloads the wafer 100 from the chuck table 20. Specifically, the control unit 7 positions the chuck table 20, which holds the wafer 100, at a wafer holding position on the -Y direction side. Then, as shown in FIG. 2, the control unit 7 causes the moving mechanism 50 of the unloading mechanism 172 to pivot the rotating column 82 and the arm 81, thereby positioning the transfer pad 80 above the wafer 100, which is held by suction on the holding surface 22 of the chuck table 20. At this time, the control unit 7 adjusts the positional relationship between the center of the transfer pad 80 and the center of the back surface 102, which is the upper surface of the wafer 100, so that their horizontal positions approximately coincide.

[0077] At this time, the first air supply valve 485 and the water supply valve 495 of the fluid distribution mechanism 46 are closed, while the first suction valve 475 is open. As a result, the holding surface 22 of the chuck table 20 is connected to the first suction source 47, and the wafer 100 is held by suction. Also, part of the processing water used in the grinding process enters the communication passage 470 of the fluid distribution mechanism 46 via the holding surface 22.

[0078] Additionally, the second air supply valve 96 and the second suction valve 98 connected to the suction surface 92 of the transfer pad 80 of the unloading mechanism 172 are closed.

[0079] Next, the control unit 7 causes the moving mechanism 50 to lower the rotating column 82, thereby lowering the transport pad 80 suspended at the tip of the arm 81. By lowering the transport pad 80 in this manner, the control unit 7 brings the suction surface 92 of the transport pad 80 into contact with the back surface 102 of the wafer 100, as shown in FIG.

[0080] Thereafter, the control unit 7 opens the second suction valve 98 to connect the second suction source 99 to the suction surface 92 of the transfer pad 80 via the fluid path 89, and the wafer 100 is held by suction on this suction surface 92.

[0081] Next, the control unit 7 closes the first suction valve 475 of the fluid distribution mechanism 46. This stops the suction of the wafer 100 by the holding surface 22 of the chuck table 20. Furthermore, the control unit 7 opens the first air supply valve 485 of the fluid distribution mechanism 46. This causes the holding surface 22 to communicate with the first suction source 47 via the air supply path 481 and the communication path 470, and air is supplied to the holding surface 22.

[0082] As a result, air is ejected from the holding surface 22 of the chuck table 20, and the suction force of the holding surface 22 holding the wafer 100 disappears. At this time, the control unit 7 controls the air adjustment unit 483, which is a throttle valve, to set the flow rate of air supplied to the holding surface 22 via the air supply path 481 and the communication passage 470 to, for example, a smaller amount than before, so that the machining water that has entered the communication passage 470 remains in the communication passage 470 and only air is supplied to the holding surface 22. In other words, the air adjustment unit 483 is configured to set the flow rate of air supplied to the holding surface 22 so that machining water remains in the communication passage 470 and only air is supplied to the holding surface 22 when the first suction source 47 is connected to the holding surface 22 by closing the first suction valve 475 and opening the first air supply valve 485 to supply air to the holding surface 22.

[0083] The control unit 7 may perform the control as follows. The control unit 7 lowers the rotating column 82 using the movement mechanism 50, thereby lowering the transfer pad 80 suspended at the tip of the arm 81. As the rotating column 82 starts to lower, the first suction valve 475 of the fluid distribution mechanism 46 is closed. Then, when the suction surface 92 of the transfer pad 80 comes into contact with the back surface 102 of the wafer 100, the second suction valve 98 may be opened, and the first air supply valve 485 of the fluid distribution mechanism 46 may be opened to supply air to the holding surface 22. Alternatively, the rotating column 82 may be lowered with the second suction valve 98 open, so that the suction surface 92 of the transfer pad 80 comes into contact with the back surface 102 of the wafer 100 .

[0084] Next, the control unit 7 controls the moving mechanism 50 to move the transfer pad 80, thereby transferring the wafer 100. That is, after a preset time (predetermined waiting time) has elapsed since the first air supply valve 485 was opened, the control unit 7 causes the moving mechanism 50 to lift the transfer pad 80 holding the wafer 100, as shown in FIG. 3, to remove the wafer 100 from the holding surface 22. That is, in this embodiment, under the control of the control unit 7, the moving mechanism 50, which is an elevation mechanism, is configured to lift the transfer pad 80, which suction-holds the wafer 100 on the holding surface 22, to remove the wafer 100 from the holding surface 22, after a preset time has elapsed since the first air supply valve 485 was opened.

[0085] Thereafter, the control unit 7 controls the moving mechanism 50 to transport the wafer 100 to, for example, the spinner cleaning mechanism 156 shown in Fig. 1. Thereafter, the control unit 7 controls the robot 155 to load the wafer 100 into the first cassette 153 or the second cassette 154 after cleaning and drying the wafer 100 with the spinner cleaning mechanism 156.

[0086] As described above, in this embodiment, when the wafer 100 is detached from the holding surface 22 by supplying air to the holding surface 22, the flow rate of air supplied to the holding surface 22 (communicating passage 470) is narrowed by the air adjustment unit 483, thereby preventing the processing water in the communicating passage 470 from being pushed up toward the holding surface 22 by the air, and allowing only the air to reach the holding surface 22 through the communicating passage 470 while leaving the processing water in the communicating passage 470.

[0087] Therefore, compared to a configuration in which both air and processing water reach the holding surface 22, it is possible to shorten the time from when the first air supply valve 485 is opened until the air reaches the holding surface 22. Therefore, in this embodiment, it is possible to shorten the time required to separate the wafer 100 from the holding surface 22.

[0088] Furthermore, since the processing water is prevented from being sprayed out from the holding surface 22, it is possible to prevent the processing water containing grinding debris from contaminating the underside (surface 101) of the wafer 100 and the suction surface 92 of the transfer pad 80. This makes it possible to eliminate the need for a cleaning unit for cleaning the underside of the wafer and the suction surface of the transfer pad, as disclosed in Patent Document 2.

[0089] In addition, in a conventional configuration in which a mixed fluid of water and air is supplied to the holding surface 22 when a plate-shaped workpiece such as a wafer 100 is removed from the chuck table 20, for example, the flow rate of air supplied from the first air source 48 to the connecting passage 470 is 40 to 50 (L / min), and the amount of water supplied from the first water supply source 49 to the connecting passage 470 is 0.7 to 1.0 (L / min).

[0090] On the other hand, in this embodiment, when the wafer 100 is removed from the chuck table 20, the flow rate of the air supplied from the first air source 48 to the communicating passage 470 is, for example, 1 to 10 (L / min), and the amount of water supplied from the first water supply source 49 to the communicating passage 470 is 0 (L / min). By limiting the flow rate of the air in this manner, it is possible to ensure that only the air reaches the holding surface 22 while leaving the processing water in the communicating passage 470.

[0091] Furthermore, in this embodiment, after a predetermined waiting time has elapsed since the first air supply valve 485 was opened, the control unit 7 causes the moving mechanism 50 to raise the transfer pad 80 holding the wafer 100, thereby removing the wafer 100 from the holding surface 22. This predetermined waiting time is longer than the time it takes for the holding surface 22 to lose its suction force after the first air supply valve 485 is opened.

[0092] In a conventional configuration in which a mixed fluid is supplied to the holding surface 22, the waiting time, i.e., the time from when the first air supply valve 485 and the water supply valve 495 are opened until the transfer pad 80 starts to rise, is set to, for example, 2 to 5 seconds. The time from when the transfer pad 80 starts to rise until the transfer pad 80 finishes rising is set to, for example, 3 to 5 seconds. In contrast, in this embodiment, since only air is allowed to reach the holding surface 22, the waiting time, i.e., the time from when the first air supply valve 485 is opened until the transfer pad 80 starts to rise, is set to, for example, 2 to 5 seconds. Furthermore, because no surface tension of water is generated between the holding surface 22 and the wafer 100, the time from when the transfer pad 80 starts to rise until the transfer pad 80 finishes rising can be set to, for example, 2 to 3 seconds. In other words, in this embodiment, the speed at which the transfer pad 80 is raised can be set faster than in the conventional configuration.

[0093] The waiting time may be set depending on the size of the chuck table 20 and the size of the transfer pad 80. That is, the larger the chuck table 20, the longer it takes for air to be distributed throughout the porous plate 21, so the waiting time (i.e., the time for supplying air to the porous plate 21) may be made longer. Furthermore, if the transfer pad 80 is large, the weight of the transfer pad 80 acting on the wafer 100 when the wafer 100 is held by the transfer pad 80 increases. Therefore, in order to lift the wafer 100 from the holding surface 22, the waiting time may be lengthened and the air pressure inside the porous plate 21 may be increased. [Explanation of symbols]

[0094] 1: grinding device, 3: grinding mechanism, 4: grinding feed mechanism, 7: control unit, 10: first device base, 11: first device base, 12: second device base, 13: column, 14: opening, 15: bellows cover, 16: cover, 17: grinding water supply source, 20: chuck table, 21: porous plate, 22: holding surface, 23: frame body, 25: Rotation mechanism, 30: Spindle, 31: Spindle housing, 32: motor, 33: wheel mount, 34: grinding wheel, 35: wheel base, 36: Grinding wheel, 38: Thickness measuring device, 40: Z-axis ball screw, 41: Z-axis guide rail, 42: Z-axis motor, 43: Z-axis moving table, 44: holder, 46: fluid distribution mechanism, 47: First suction source, 48: First air source, 49: First water supply source, 50: moving mechanism, 51: column, 52: ball screw, 53: guide rail, 54: Motor, 55: Nut, 57: Encoder, 80: Transport pad, 81: Arm, 82: Rotating column part, 83: Support column, 84: Disc member, 85: through hole, 86: bolt, 87: shaft, 88: head, 89: fluid path, 90: pad holding portion, 91: frame body, 92: suction surface, 96: second air supply valve, 97: Second air source, 98: Second suction valve, 99: Second suction source, 100: wafer, 101: front surface, 102: back surface, 140: temporary placement mechanism, 141: alignment member, 142: temporary placement table, 151: first cassette stage, 152: second cassette stage, 153: first cassette, 154: second cassette, 155: robot, 156: Spinner cleaning mechanism, 157: Spinner table, 158: Nozzle, 170: Loading mechanism, 172: Unloading mechanism, 231: Recess, 440: Measuring device, 470: Communication path, 471: Suction path, 473: Suction flow rate adjustment section, 475: first suction valve, 481: air supply passage, 483: air adjustment section, 485: first air supply valve, 491: water supply passage, 493: water adjustment unit, 495: Water supply valve, 821: Swivel shaft, 841: Through hole

Claims

1. A processing device comprising: a chuck table that sucks and holds a plate-shaped workpiece by a holding surface; and a processing mechanism that processes the plate-shaped workpiece while supplying processing water to the plate-shaped workpiece held on the chuck table, the chuck table includes a porous plate having the holding surface on an upper surface thereof, and a frame having a recess for accommodating the porous plate so as to expose the holding surface; a communication passage that opens to a bottom of the recess and is connected to the holding surface; a suction path connected to the communication path and connecting the holding surface and a suction source; a suction valve disposed in the suction path and configured to open and close to switch a communication state between the holding surface and the suction source; an air supply path connected to the communication path and connecting the holding surface with an air source; an air supply valve disposed in the air supply passage and configured to switch a communication state between the holding surface and the air source by opening and closing; a throttle valve that sets the flow rate of air sent from the air source to the holding surface when the air supply valve is open; The throttle valve is configured to set the flow rate of air supplied to the holding surface so that, when the suction valve is closed and the air supply valve is opened to connect the air source to the holding surface and supply air to the holding surface, machining water remains in the communication passage and only air is supplied to the holding surface. Processing equipment.

2. Further provided is a conveying pad having a suction surface for suction-holding the upper surface of the plate-shaped workpiece, and a lifting mechanism for lifting and lowering the conveying pad, The lifting mechanism is configured to lift the conveying pad that suction-holds the plate-shaped workpiece on the holding surface and separate the plate-shaped workpiece from the holding surface after a preset time has elapsed since the air supply valve was opened. The processing device according to claim 1.

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