Processing equipment

Abstract

This invention provides a processing apparatus that removes a wafer from a holding surface in a short time without causing it to break. The wafer, held by a transport pad, is raised from the holding surface. When the entire lower surface of the wafer has left the holding surface, an air flow regulating valve is opened to eject air from the holding surface. As the distance between the holding surface and the wafer leaving the holding surface increases by raising the transport unit, the opening degree of the air flow regulating valve is adjusted to increase the air flow, thereby preventing the wafer from breaking and allowing it to leave the holding surface in a short time.

Description

Technical Field

[0001] This invention relates to a processing apparatus. Background Technology

[0002] The processing apparatus for processing a wafer held on a holding surface, as disclosed in Patent Document 1, uses a transfer pad to hold the processed wafer and sprays a mixture of water and air from the holding surface when the wafer leaves the holding surface.

[0003] However, there is a problem that the wafer may break due to the pressure of the mixture ejected from the holding surface. Therefore, there are inventions that gradually increase the amount of mixture ejected, as disclosed in Patent Document 2.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2007-294588

[0005] Patent Document 2: Japanese Patent Application Publication No. 2009-076720

[0006] However, there is a problem with the time spent before the wafer leaves the holding surface. Summary of the Invention

[0007] Therefore, the object of the present invention is to provide a processing apparatus that can remove a wafer from the holding surface in a short time without causing the wafer to break.

[0008] According to the present invention, a processing apparatus is provided, comprising: a chuck stage for holding a lower surface of a wafer on a holding surface; a processing unit for processing an upper surface of the wafer held on the holding surface; a conveying unit for removing the wafer held on the holding surface from the holding surface; and a control unit, the chuck stage comprising: a communication path connecting the holding surface to a water supply source; a branch disposed in the communication path; an air communication path connecting the branch to an air supply source; a water flow regulating valve disposed in the communication path between the branch and the water supply source for regulating the water flow rate; and an air flow regulating valve. It is configured in the air passage and can adjust the air flow rate. The control unit controls the following situations: the conveying unit holds the wafer held by the holding surface; the water flow regulating valve is opened to spray water from the holding surface; the wafer is removed from the holding surface by the water sprayed from the holding surface, and the conveying unit holding the wafer is raised from the holding surface; when the entire lower surface of the wafer is removed from the holding surface, the air flow regulating valve is opened to spray air from the holding surface; and the air flow rate is increased as the distance between the holding surface and the wafer removed from the holding surface increases by raising the conveying unit.

[0009] According to the present invention, a conveying unit can be used to quickly remove the wafer from the holding surface without breaking it, thereby improving productivity. Attached Figure Description

[0010] Figure 1 It is a three-dimensional view showing the entire processing device.

[0011] Figure 2 This is a cross-sectional view showing the conveying unit and the holding unit.

[0012] Figure 3 It is a graph showing the relationship between the distance between the surface and the wafer and the flow rates of water and air.

[0013] Label Explanation

[0014] 1: Processing device; 10: Base; 12: Internal base; 11: Column; 14: Workpiece; 140: Upper surface; 141: Lower surface; 16: Thickness measuring unit; 9: Control unit; 2: Holding unit; 20: Suction part; 200: Holding surface; 21: Frame; 210: Upper surface of the frame; 23: Base; 25: Rotation axis; 26: Rotation unit; 260: Motor; 262: Drive shaft; 263: Drive pulley; 264: Transmission belt; 265: Driven pulley; 266: Driven shaft; 267: Rotary joint; 29: Connecting component ; 291: Support column; 243: Connecting path; 2400: Suction valve; 2410: Air valve; 2420: Water valve; 2430: Suction connecting path; 2431: Air connecting path; 2432: Water connecting path; 27: Cover; 28: Fold; 3: Grinding unit; 30: Spindle; 31: Housing; 32: Spindle motor; 33: Mounting base; 34: Grinding wheel; 340: Grinding tool; 341: Grinding wheel base; 342: Lower surface; 4: Grinding feed unit; 40: Ball screw; 41: Guide rail; 42: Z-axis motor; 420: Encoder ; 43: Lifting plate; 44: Support; 45: Rotation axis; 5: Horizontal movement mechanism; 50: Ball screw; 51: Guide rail; 52: Y-axis motor; 53: Movable plate; 61: First conveying unit; 62: Second conveying mechanism; 60: Conveying pad; 600: Lower surface; 601: Air flow path; 602: Support component; 603: Upper surface; 63: Connecting component; 6020: Flange; 630: Through hole; 64: Lifting mechanism; 642: Ball screw; 643: Movable part; 640: Motor; 641: Encoder; 65: Arm; 6 6: Shaft; 680: Suction source; 681: Suction valve; 6810: Suction path; 690: Air supply source; 691: Air valve; 6910: Air supply path; 70: Box; 700: Box platform; 71: Robot; 710: Robot arm; 711: Holding surface; 712: Shaft; 72: Alignment mechanism; 720: Temporary placement area; 73: Rotary unit; 730: Rotary shaft; 731: Encoder; 732: Motor; 74: Rotary cleaning unit; 740: Rotary worktable; 741: Cleaning water supply nozzle; 742: Cleaning area. Detailed Implementation

[0015] Figure 1 The processing apparatus 1 shown is a grinding apparatus that uses processing unit 3 to process the upper surface 140 of wafer 14 held by holding surface 200. The material of wafer 14 is, for example, SiC, and its thickness before processing is about 2 cm. The structure of processing apparatus 1 will be described below.

[0016] like Figure 1As shown, the processing device 1 includes: a base 10 extending along the Y-axis; and a column 11 erected on the +Y direction side of the base 10.

[0017] A machining feed mechanism 4 is provided on the side of the column 11 in the -Y direction, which supports the machining unit 3 so that it can be raised and lowered. The machining unit 3 is, for example, a grinding unit, which has: a spindle 30 having an axis in the Z-axis direction; a housing 31 that supports the spindle 30 so that it can rotate; a spindle motor 32 that drives the spindle 30 to rotate about the axis in the Z-axis direction; a mounting base 33 that is connected to the lower end of the spindle 30; and a grinding wheel 34 that is detachably mounted on the lower surface of the mounting base 33.

[0018] The grinding wheel 34 has a grinding wheel base 341 and a plurality of generally cuboid grinding tools 340 arranged in a ring on the lower surface of the grinding wheel base 341. The lower surface of the grinding tools 340 is the grinding surface 342 that contacts the wafer 14.

[0019] The spindle 30 is rotated by the spindle motor 32, thereby rotating the mounting base 33 connected to the spindle 30 and the grinding wheel 34 mounted on the lower surface of the mounting base 33 together.

[0020] The machining feed mechanism 4 includes: a ball screw 40 having a rotation axis 45 in the Z-axis direction; a pair of guide rails 41 arranged parallel to the ball screw 40; a Z-axis motor 42 that causes the ball screw 40 to rotate about the rotation axis 45; a lifting plate 43 with a nut inside that is screwed into the ball screw 40, and the side of the lifting plate 43 slidingly contacting the guide rails 41; and a support 44 connected to the lifting plate 43 to support the machining unit 3.

[0021] When the ball screw 40 is driven by the Z-axis motor 42 to rotate around the rotation axis 45, the lifting plate 43 is guided by the guide rail 41 to move up and down in the Z-axis direction, and the grinding wheel 34 of the processing unit 3 held by the support 44 moves in the Z-axis direction.

[0022] A holding unit 2 is provided on the base 10. The holding unit 2 is, for example, a chuck stage for holding the wafer 14. The holding unit 2 has a circular plate-shaped suction part 20 and a frame 21 that supports the suction part 20. The suction part 20 is, for example, a porous component with multiple fine holes. The upper surface of the suction part 20 is a holding surface 200 that holds the lower surface 141 of the wafer 14, and the upper surface 210 of the frame 21 is formed on the same plane as the holding surface 200.

[0023] An inner base 12 is disposed inside the base 10. A horizontal moving mechanism 5, which moves the holding unit 2 in the horizontal direction, is disposed on the inner base 12. The horizontal moving mechanism 5 includes: a ball screw 50 having a center in the Y-axis direction; a pair of guide rails 51 arranged parallel to the ball screw 50; a Y-axis motor 52 connected to the ball screw 50 to rotate the ball screw 50; and a movable plate 53, the nut at its bottom of which is screwed into the ball screw 50 and moves along the guide rails 51 in the Y-axis direction. It is configured such that when the ball screw 50 is rotated by driving it via the Y-axis motor 52, the movable plate 53 is guided by the guide rails 51 to move horizontally in the Y-axis direction.

[0024] Multiple (in) are vertically mounted on the movable plate 53. Figure 1 There are two support columns 291, and annular connecting members 29 are supported on the support columns 291. The annular connecting members 29 support the base 23 so that it can rotate. Figure 2 As shown, the retaining unit 2 is mounted on the base 23, and the frame 21 is supported on the base 23. That is, the retaining unit 2 is disposed on the movable plate 53 by means of the support column 291, the connecting member 29 and the base 23.

[0025] A rotating unit 26 for rotating the base 23 is disposed below the holding unit 2. The rotating unit 26 is, for example, a pulley mechanism, comprising: a drive shaft 262, which is rotatable about the Z-axis via a motor 260; a drive pulley 263 connected to the upper end of the drive shaft 262; a transmission belt 264 wound around the drive pulley 263, transmitting the driving force of the drive pulley 263 to the driven pulley 265; a driven pulley 265 wound together with the drive pulley 263 on the transmission belt 264; a driven shaft 266 connected to the driven pulley 265; and a rotary joint 267 connected to the lower end of the driven shaft 266. The driven shaft 266 is connected to the base 23.

[0026] When the drive shaft 262 is rotated by the motor 260, the drive pulley 263 rotates, and the rotational force of the drive pulley 263 is transmitted to the driven pulley 265 through the transmission belt 264, causing the driven pulley 265 to rotate. Thus, the configuration is such that the driven shaft 266, connected to the driven pulley 265, rotates about the rotation axis 25 in the Z-axis direction, and the base 23, connected to the driven shaft 266, rotates about the rotation axis 25 in the Z-axis direction.

[0027] Below the holding unit 2, an attraction source 240, an air supply source 241, and a water supply source 242 are disposed. The holding unit 2 has a communication path 243 that connects the holding surface 200 to the water supply source 242. The communication path 243 is formed, for example, in a manner that passes through the interior of the frame 21, the base 23, the driven shaft 266, and the rotary joint 267, and protrudes from the side of the rotary joint 267 to the exterior of the rotary joint 267.

[0028] A first branch 248 and a second branch 249 are provided on the connecting path 243. The connecting path 243 branches into an attraction connecting path 2430, an air connecting path 2431, and a water connecting path 2432 through the first branch 248 and the second branch 249. The attraction connecting path 2430 connects the first branch 248 to the attraction source 240, the air connecting path 2431 connects the second branch 249 to the air supply source 241, and the water connecting path 2432 connects the second branch 249 to the water supply source 242.

[0029] A suction valve 2400 and a suction force adjustment valve 2440 are provided between the first branch 248 and the suction source 240. When the suction source 240 is operated with the suction valve 2400 open, the suction force generated by the suction source 240 is transmitted to the holding surface 200 of the suction section 20 through the connecting passage 243.

[0030] For example, with the wafer 14 placed on the holding surface 200, by opening the suction valve 2400 and activating the suction source 240, the wafer 14 can be attracted and held on the holding surface 200. Furthermore, by adjusting the throttling degree of the suction adjustment valve 2440, the intensity of the suction force transmitted to the holding surface 200 can be adjusted.

[0031] An air valve 2410 and an air flow regulating valve 2441 are provided between the second branch 249 and the air supply source 241. When air is supplied by the air supply source 241 with the air valve 2410 open, the supplied air is transmitted to the suction section 20 through the connecting passage 243 and injected from the plurality of fine holes formed in the holding surface 200 toward the space above the holding surface 200. In addition, by adjusting the throttling degree of the air flow regulating valve 2441, the flow rate of the air injected from the holding surface 200 can be adjusted.

[0032] A water valve 2420 and a water flow regulating valve 2442 are provided between the second branch 249 and the water supply source 242. When water is supplied from the water supply source 242 with the water valve 2420 open, the supplied water is transmitted to the suction section 20 through the connecting passage 243 and sprayed from multiple fine holes in the holding surface 200. In addition, the flow rate of the water sprayed from the holding surface 200 can be adjusted by adjusting the throttling degree of the water flow regulating valve 2442.

[0033] like Figure 1 As shown, for example, a cover 27 and pleats 28 connected to the cover 27 in a telescopic manner are provided. When the holding unit 2 moves in the Y-axis direction, the cover 27 moves together with the holding unit 2 in the Y-axis direction, and the pleats 28 telescopic.

[0034] A cassette stage 700 is provided on the -Y direction side of the base 10. A cassette 70 is placed on the cassette stage 700. For example, multiple wafers 14 before grinding are stored in the cassette 70, and wafers 14 after grinding are also stored in the cassette 70.

[0035] A robot 71 is disposed on the +Y direction side of the box 70. The robot 71 has a robot arm 710 and a shaft 712 supporting the robot arm 710 so that it can rotate. An attraction source (not shown) is connected to the holding surface 711 of the robot arm 710, which can attract and hold the chip 14 on the holding surface 711 of the robot arm 710.

[0036] By attracting and holding the chip 14 stored in the box 70 onto the holding surface 711 of the robot arm 710 and driving the shaft 712 to rotate the robot arm 710, the chip 14 can be taken out of the box 70 and transported to the temporary storage area 720.

[0037] A temporary placement area 720 is provided on the +X direction side of the movable area of ​​the robot 71 for temporarily placing the wafer 14 before grinding, and a cleaning area 742 is provided on the -X direction side of the movable area of ​​the robot 71 for cleaning the wafer 14 after grinding.

[0038] A positioning mechanism 72 is provided in the temporary storage area 720. The positioning mechanism 72 is connected to a rotating unit 73, which has a rotating shaft 730, an encoder 731, and a motor 732, and is located inside the base 10. It can rotate about the axis in the Z-axis direction. The wafer 14, which is taken out of the box 70 and placed in the temporary storage area 720, is aligned to a predetermined position by the positioning mechanism 72.

[0039] A rotary cleaning unit 74 is provided in the cleaning area 742. The rotary cleaning unit 74 has a rotary stage 740 for holding the wafer 14 and a cleaning water supply nozzle 741 for spraying cleaning water toward the wafer 14 held by the rotary stage 740. In addition, the rotary stage 740 is connected to a rotary unit (not shown) and can rotate about the axis in the Z-axis direction.

[0040] For example, the wafer 14 can be cleaned by rotating the rotary table 740 while holding the ground wafer 14 on the upper surface of the rotary table 740 and supplying cleaning water from the cleaning water supply nozzle 741.

[0041] A first transport unit 61 is disposed adjacent to the temporary storage area 720 to transport the workpiece 17, which has been aligned in the temporary storage area 720, to the holding surface 200 of the holding unit 2. The first transport unit 61 has a circular transport pad 60 that attracts and holds the upper surface 140 of the wafer 14. Figure 2 As shown, an airflow path 601 is formed inside the transport pad 60. The airflow path 601 is formed, for example, in a ring shape throughout the interior of the transport pad 60, and opens at the lower surface 600 of the transport pad 60 to connect with the space outside the transport pad 60.

[0042] Furthermore, the airflow path 601 branches into an air supply path 6910 and a suction path 6810 on the outside of the conveying pad 60. The air supply path 6910 is connected to the air supply source 690, and the suction path 6810 is connected to the suction source 680. An air valve 691 is provided on the air supply path 6910, and a suction valve 681 is provided on the suction path 6810.

[0043] Additionally, near the outer periphery of the lower surface 600 of the transport pad 60, two O-rings 609 of different diameters are respectively provided on the inner and outer periphery sides of the opening portion of the air flow path 601 on the lower surface 600. The O-rings 609 function as sealing components, and when the wafer 14 is attracted and held on the transport pad 60, the O-rings 609 can be tightly attached to the upper surface 140 of the wafer 14 to improve the holding strength of the wafer 14.

[0044] Air is supplied from air supply source 690 with air valve 691 open, and the supplied air is injected from the lower surface 600 of the conveying pad 60 through air flow path 601. Conversely, by activating suction source 680 with air valve 691 closed and suction valve 681 open, the resulting suction force is transmitted to the lower surface 600 of the conveying pad 60 through air flow path 601.

[0045] For example, by transferring the attractive force generated by the attraction source 680 to the lower surface 600 of the transport pad 60 while the upper surface 140 of the wafer 14 is in contact with the lower surface 600 of the transport pad 60, the wafer 14 can be attracted and held on the lower surface 600 of the transport pad 60.

[0046] Three (on the upper surface 603 of the conveying pad 60) are fixed. Figure 2 Two support members 602 are shown. The support member 602 extends along the Z-axis and has a flange 6020 formed on its upper part. The support member 602 passes through the through hole 630 formed in the connecting member 63, and the flange 6020 is supported by the connecting member 63.

[0047] An arm 65 is connected to the connecting member 63, and a shaft 66, erected vertically along the Z-axis, is connected to the end of the arm 65 that is not connected to the transport pad 60. A rotating unit (not shown) is connected to the shaft 66, which allows the shaft 66 to rotate about the Z-axis axis. The configuration is such that by rotating the shaft 66 using this rotating unit, the arm 65 rotates, thereby moving the transport pad 60 between the temporary storage area 720 and the holding surface 200.

[0048] Additionally, a lifting mechanism 64 is provided on the shaft portion 66. The lifting mechanism 64 includes: a ball screw 642 extending along the Z-axis; a motor 640 that rotates the ball screw 642 about its Z-axis axis; an encoder 641 that controls the rotation of the motor 640; and a movable part 643, whose internal nut engages with the ball screw 642, thereby allowing the movable part 643 to move up and down in the Z-axis direction. The movable part 643 is connected to the shaft portion 66.

[0049] The configuration is such that when the ball screw 642 is rotated by the motor 640, the movable part 643 moves up and down in the Z-axis direction while sliding contacting the ball screw 642. Accompanyingly, the shaft 66 connected to the movable part 643, the arm 65 connected to the shaft 66, and the conveying pad 60 supported on the arm 65 move up and down in the Z-axis direction as a whole.

[0050] like Figure 1 As shown, a second conveying mechanism 62 is provided on the -X direction side of the first conveying unit 61 to move the ground wafer 14 from the holding surface 200 to the cleaning area 742. The second conveying mechanism 62 is configured in the same way as the first conveying unit 61, so the parts of the second conveying mechanism 62 are labeled with the same reference numerals as the parts of the first conveying unit 61.

[0051] A thickness measuring unit 16 is disposed near the holding unit 2 on the base 10. The thickness measuring unit 16 may be, for example, a contact height gauge, and the thickness of the wafer 14 can be measured by contacting the height gauge with the upper surface 140 of the wafer 14 and the upper surface 210 of the frame 21.

[0052] The processing device 1 has a control unit 9 that controls each action of the processing device 1.

[0053] When grinding wafer 14 using processing equipment 1, firstly use Figure 1 The robot 71 shown pulls a chip 14 out of the box 70 and places it temporarily in the temporary placement area 720, and then uses the alignment mechanism 72 to align it.

[0054] After alignment using the alignment mechanism 72, the first transfer unit 61 transfers the wafer 14, which is temporarily placed in the temporary placement area 720, onto the holding surface 200 of the holding unit 2. Specifically, firstly, the wafer 14 is transferred from the temporary placement area 720 onto the holding surface 200 of the holding unit 2. Figure 2 The shaft 66 shown rotates, thereby rotating the arm 65 and positioning the transport pad 60 above the wafer 14 placed in the temporary storage area 720.

[0055] Then, the lifting mechanism 64 is used to move the transport pad 60 in the -Z direction, so that the lower surface 600 of the transport pad 60 contacts the upper surface 140 of the wafer 14. With the upper surface 140 of the wafer 14 in contact with the lower surface 600 of the transport pad 60, the attraction source 680 is activated to transfer the attraction force generated by the attraction source 680 to the lower surface 600 of the transport pad 60, thereby attracting and holding the wafer 14 on the lower surface 600 of the transport pad 60.

[0056] Furthermore, while holding the wafer 14 on the lower surface 600 of the transport pad 60, the arm 65 is rotated to position the wafer 14 held on the lower surface 600 of the transport pad 60 above the holding surface 200. Then, the transport pad 60 is lowered to place the wafer 14 on the holding surface 200. With the wafer 14 on the holding surface 200, the suction valve 2400 is opened, transmitting the suction force generated by the suction source communicating with the holding surface 200 to the holding surface 200, thereby holding the wafer 14 on the holding surface 200. Then, the suction force acting on the lower surface 600 of the transport pad 60 is released.

[0057] Next, use Figure 1 The horizontal moving mechanism 5 shown moves the wafer 14 held by the holding surface 200 in the +Y direction and positions it below the processing unit 3.

[0058] And, using Figure 2 The rotating unit 26 shown causes the holding unit 2 to rotate about the rotation axis 25. As a result, the wafer 14 held by the holding surface 200 rotates about the rotation axis 25. Furthermore, prior use... Figure 1 The spindle motor 32 shown rotates the grinding wheel 340.

[0059] With the wafer 14 held by the holding surface 200 rotating and the grinding wheel 340 rotating, the grinding wheel 340 is lowered in the -Z direction using the machining feed mechanism 4. This brings the grinding surface 342 of the grinding wheel 340 into contact with the upper surface 140 of the wafer 14 held by the holding surface 200. With the grinding surface 342 of the grinding wheel 340 in contact with the upper surface 140 of the wafer 14, the grinding wheel 340 is further lowered in the -Z direction, thereby performing grinding on the wafer 14. During the grinding of the wafer 14, the thickness of the wafer 14 is measured using the thickness measuring unit 16. The grinding process ends when the wafer 14 has been ground to a predetermined thickness.

[0060] After the grinding process of wafer 14 is completed, the grinding wheel 340 is raised in the +Z direction using the machining feed mechanism 4, so that the grinding wheel 340 moves away from the upper surface 140 of wafer 14 in the +Z direction. Then, the wafer 14 held by the holding surface 200 is moved in the -Y direction using the horizontal movement mechanism 5.

[0061] Then, the wafer 14 held on the holding surface 200 is removed from the holding surface 200 using the second conveying mechanism 62. Specifically, the removal of the wafer 14 by the second conveying mechanism 62 is performed by controlling the processing apparatus 1 via the control unit 9 as follows. First, as... Figure 2 As shown, after the transport pad 60 of the second transport mechanism 62 is positioned above the wafer 14, the lifting mechanism 64 lowers the transport pad 60 in the -Z direction, so that the lower surface 600 of the transport pad 60 contacts the upper surface 140 of the wafer 14. Furthermore, while the upper surface 140 of the wafer 14 is in contact with the lower surface 600 of the transport pad 60, the attraction source 680 is activated to transfer the attraction force generated by the attraction source 680 to the lower surface 600 of the transport pad 60, thereby attracting and holding the wafer 14 on the lower surface 600 of the transport pad 60.

[0062] Additionally, the suction valve 2400 is closed to prevent the suction force generated by the suction source 240 from being transmitted to the holding surface 200. Meanwhile, the water valve 2420 and the water flow regulating valve 2442 are opened to supply water from the water supply source 242. As a result, water is supplied to the interior of the suction section 20 through the water connection passage 2432 and the connection passage 243, and is ejected from the holding surface 200 in the +Z direction.

[0063] When water is sprayed from the holding surface 200, a water film forms between the holding surface 200 and the lower surface 141 of the wafer 14. This water film causes the transport pad 60 holding the wafer to float, separating the wafer 14 from the holding surface 200. In other words, the holding surface 200 supports the transport pad 600 holding the wafer through the water film. As a result, the flange 6020 floats from the connecting member 63. During this stage, water flows throughout the entire holding surface 200, forming a water film over the entire area between the holding surface 200 and the lower surface 141 of the wafer 14.

[0064] In this state, the lifting mechanism 64 is used to move the arm in the +Z direction, thereby connecting the member 63 to support the flange 6020, and causing the transport pad 60 holding the wafer 14 to move in the +Z direction and rise from the holding surface 200.

[0065] When the connecting member 63 supports the flange portion 6020, the air valve 2410 and the air flow regulating valve 2441 are opened, and air is supplied from the air supply source 241. The air supplied from the air supply source 241 is mixed with water in the air communication passage 243, and as a mixed fluid, it is ejected from the holding surface 200 in the +Z direction through the communication passage 243.

[0066] After the entire lower surface 141 of the wafer 14 leaves the holding surface 200, the lifting mechanism 64 moves the wafer 14 held by the transport pad 60 in the +Z direction. Furthermore, in conjunction with the increase in the distance between the holding surface 200 and the wafer 14 leaving the holding surface 200, the opening of the air flow regulating valve 2441 is gradually increased, increasing the amount of air ejected from the holding surface 200. In this way, air is introduced into the water film with a gap formed between the holding surface and the lower surface of the wafer 14, thereby breaking the surface tension of the water film and making it easier for the wafer 14 to leave the water film.

[0067] exist Figure 3 The graph shown is an example of the relationship between the distance between the holding surface 200 and the wafer 14 that is away from the holding surface 200 and the flow rate of air and water ejected from the holding surface 200.

[0068] When the distance between the holding surface 200 and the wafer 14 that is away from the holding surface 200 is 0 mm to 2 mm, the air flow rate is controlled at 6.5 liters / min and the water flow rate is 1.4 liters / min. When the distance exceeds 2 mm, the air flow rate is controlled at 39 liters / min and the water flow rate is 1.00 liters / min.

[0069] Furthermore, when the wafer 14 moves a predetermined distance from the holding surface 200, the shaft 66 is rotated, causing the arm 65 to rotate as well. After positioning the wafer 14 held by the transport pad 60 in the cleaning area 742, the lifting mechanism 64 lowers the wafer 14. This holds the wafer 14 on the upper surface of the rotary table 740. While rotating the rotary table 740, cleaning water is supplied to the upper surface 140 of the wafer 14 from the cleaning water supply nozzle 741, thereby washing away grinding debris and other contaminants adhering to the upper surface 140 of the wafer 14. After the upper surface 140 of the wafer 14 is washed, the robot 71 collects the wafer 14 into the box 70.

[0070] In the processing apparatus 1, when the second conveying mechanism 62 is used to remove the ground wafer 14 from the holding surface 200, water is sprayed from the holding surface 200 toward the lower surface 141 of the wafer 14 as the wafer 14 leaves the holding surface 200, thereby forming a water film on the holding surface 200. The water film causes the conveying pad 600 holding the wafer 14 to float, allowing the wafer 14 to leave the holding surface 200. The holding surface 200 supports the conveying pad holding the wafer through the water film. Then, the lifting mechanism 64 is used to raise the wafer 14 and allow the wafer 14 to leave the holding surface 200. Therefore, the wafer 14 can leave the holding surface 200 safely without breaking.

[0071] In addition, after the wafer 14 has completely left the holding surface 200, the lifting mechanism 64 is used to raise the wafer 14 while spraying air from the holding surface 200 to the water film. As the distance between the holding surface 200 and the lower surface 141 of the wafer 14 increases, the flow rate of the air sprayed from the holding surface 200 increases, thus enabling the wafer 14 to rise quickly from the holding surface 200.

[0072] In the processing apparatus 1, it is preferable to be able to safely and quickly remove the wafer 14 from the holding surface 200 when, for example, a fault occurs during the grinding process of the wafer 14 and it is necessary to remove the wafer 14 midway through grinding. In particular, wafers with a modified layer are more prone to breakage before the grinding process for removing the modified layer is performed. However, if, during the grinding process of such wafers using the processing apparatus 1 for removing the modified layer, it is necessary to remove the wafer from the holding surface 200 due to certain circumstances, the wafer can be safely and quickly removed from the holding surface 200.

Claims

1. A processing apparatus, wherein the processing apparatus has: a chuck table that holds a lower surface of a wafer on a holding surface; a processing unit that processes an upper surface of the wafer held by the holding surface; a conveyance unit that conveys the wafer held by the holding surface from the holding surface; and a control unit, the chuck table includes: a communication path that communicates the holding surface with a water supply source; a branch portion that is provided to the communication path; an air communication path that communicates the branch portion with an air supply source; a water flow rate adjustment valve that is provided to the communication path between the branch portion and the water supply source, and adjusts a flow rate of water; and an air flow rate adjustment valve that is provided to the air communication path, and is capable of adjusting a flow rate of air, the control unit controls: the conveyance unit to hold the wafer held by the holding surface; the water flow rate adjustment valve to be opened to spray water from the holding surface toward the lower surface of the wafer to form a water film on the holding surface; the wafer to be separated from the holding surface by the water sprayed from the holding surface, and the conveyance unit holding the wafer to be raised from the holding surface; the air flow rate adjustment valve to be opened to spray air from the holding surface when the entire lower surface of the wafer is separated from the holding surface; and the opening degree of the air flow rate adjustment valve to be increased to increase the flow rate of the air as the distance between the holding surface and the wafer separated from the holding surface is increased by raising the conveyance unit.

2. The processing apparatus according to claim 1, wherein the water flow rate adjustment valve is capable of adjusting the flow rate of water to be sprayed from the holding surface toward the lower surface of the wafer to be held by the holding surface.

3. The processing apparatus according to claim 1, wherein the air flow rate adjustment valve is capable of adjusting the flow rate of air to be sprayed from the holding surface toward the lower surface of the wafer separated from the holding surface.

4. The processing apparatus according to claim 1, wherein the water flow rate adjustment valve is capable of adjusting the flow rate of water to be sprayed from the holding surface toward the lower surface of the wafer to be held by the holding surface, and the air flow rate adjustment valve is capable of adjusting the flow rate of air to be sprayed from the holding surface toward the lower surface of the wafer separated from the holding surface.

5. The processing apparatus according to claim 1, wherein the water flow rate adjustment valve is capable of adjusting the flow rate of water to be sprayed from the holding surface toward the lower surface of the wafer to be held by the holding surface, and the air flow rate adjustment valve is capable of adjusting the flow rate of air to be sprayed from the holding surface toward the lower surface of the wafer separated from the holding surface, and the control unit controls the water flow rate adjustment valve and the air flow rate adjustment valve to be opened to spray water and air from the holding surface toward the lower surface of the wafer to be held by the holding surface.

6. The processing apparatus according to claim 1, wherein the water flow rate adjustment valve is capable of adjusting the flow rate of water to be sprayed from the holding surface toward the lower surface of the wafer to be held by the holding surface, and the air flow rate adjustment valve is capable of adjusting the flow rate of air to be sprayed from the holding surface toward the lower surface of the wafer separated from

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