Processing equipment

Abstract

To transfer a wafer to a cleaning unit while maintaining a state where a water layer is formed onto the upper surface.SOLUTION: A processing device 1 comprises: a chuck table 10; a processing unit 20; a first transfer unit 61 and a second transfer unit 62; and a control part 90. The second transfer unit 62 comprises a plurality of water injection ports 781 that is opened to a lower surface of a plate 66, and injects water so as to uniformly apply a pressure to a processed surface of a wafer 100. The control part 90 forms a mixed liquid layer 92 between a holding surface 11 and a lower surface of the wafer 100 by injecting mixed fluid of water and an air from the holding surface 11, and forms a water layer 91 between the processed surface of the wafer 100 and the lower surface of the plate 66 by injecting water from each water injection port 781 of the plate 66. By supporting an outer peripheral edge of the wafer 100 by a claw 671 so as to move the claw 671 to an approaching direction each other, the wafer 100 is transferred to a cleaning unit 50 by maintaining the water layer 91 formed in the wafer 100.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a processing apparatus for processing a wafer. [Background technology]

[0002] A polishing apparatus that supplies a slurry to a wafer held on a chuck table and polishes the upper surface of the wafer using a polishing pad includes a cleaning unit that cleans the upper surface of the wafer after polishing, and a transport unit that transports the wafer from the chuck table to the cleaning unit. As disclosed in Patent Documents 1-4, this transport unit holds the outer edge of the wafer with an edge clamp and forms a water layer on the upper surface before transporting. The water layer formed on the upper surface of the wafer keeps the upper surface wet, preventing the slurry from adhering.

[0003] When the edge clamp of the transport unit holds the wafer held by the chuck table, a mixture of water and air is sprayed from the holding surface of the chuck table, and the wafer floats up from the holding surface due to the mixture and is held by the edge clamp. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-056488 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-252877 [Patent Document 3] Japanese Patent Application Laid-Open No. 2011-091246 [Patent Document 4] Japanese Patent Application Laid-Open No. 2014-004658 Summary of the Invention [Problem to be solved by the invention]

[0005] Air bubbles in the liquid mixture between the holding surface and the wafer reach the outer edge of the wafer and burst. The bursting of these bubbles causes the wafer, which is floating in the liquid mixture, to flutter. This fluttering then causes the wafer to tilt. As a result, the edge clamp holds the wafer in a tilted state, and this tilt causes the water supplied to the wafer's top surface to drip down, preventing the formation of a water layer.

[0006] Therefore, a processing apparatus equipped with a wafer transport unit that transports wafers to a cleaning unit has a problem of transporting the wafer to the cleaning unit while holding the wafer horizontally and maintaining a water layer formed on the upper surface. [Means for solving the problem]

[0007] The present invention, which solves the above-mentioned problems, is a processing device for processing a wafer held on a holding surface, and includes a chuck table that holds a wafer on the holding surface, a processing unit that processes the wafer held on the holding surface, a cleaning unit that cleans the upper surface of the wafer, a transport unit that transports the wafer, and a control unit. The transport unit includes a transport pad that holds the wafer, and a moving mechanism that moves the transport pad. The transport pad includes a plate on which at least three claws are arranged at intervals in the circumferential direction of the held wafer, and a moving mechanism that moves the claws to the plate. and a plurality of water jetting ports that open on the underside of the portion of the plate surrounded by the claws and jet water so as to apply uniform pressure to the processed surface of the wafer processed by the processing unit, and the control unit moves the transport pad so that a gap is formed between the processed surface of the wafer held by the holding surface and the underside of the plate, and causes the claws to surround the outer periphery of the wafer, and jets a mixed fluid of water and air from the holding surface to form a mixed liquid layer between the holding surface and the underside of the wafer, and controls the water jetting port of the plate. injection Water from the mouth injectionthe claws surrounding the periphery of the wafer are moved in a direction approaching each other so that the claws support the outer periphery and the lower surface of the wafer; and the water layer formed on the surface of the wafer to be processed is maintained, and the wafer supported by the claws is transported to the cleaning unit. The surface of the wafer to be processed may be the bottom surface of a circular recess formed in the center of the wafer. It is also desirable that the claws be arranged on the plate so as to be able to move up and down in a direction perpendicular to the holding surface. [Effects of the Invention]

[0008] According to the present invention, even if bubbles contained in the mixed liquid layer formed in the gap between the holding surface of the chuck table and the underside of the wafer burst at the outer edge of the wafer, a water layer is supplied over the entire surface of the wafer's processing surface (upper surface) by water supplied from multiple water injection ports opened on the underside of the plate, and this water layer applies uniform downward pressure to the processing surface of the wafer, whose underside is supported by the claws, so the wafer does not flap and remains horizontal without tilting. Therefore, the wafer can be transported to the cleaning unit with the water layer formed on its upper surface, and foreign matter such as grinding debris and slurry that adheres to the processing surface of the wafer during processing does not dry out during transport of the wafer to the cleaning unit, and foreign matter adhered to the processing surface of the wafer is reliably removed in the cleaning unit. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cutaway perspective view of a polishing apparatus as one embodiment of a processing apparatus according to the present invention; [Figure 2] FIG. 1 is a perspective view of a ground wafer. [Figure 3] FIG. 2 is a perspective view of a main part of a second transport unit. [Figure 4] FIG. 10 is a cutaway side view showing the state before the transport pad of the second transport unit is lowered. [Figure 5] FIG. 5 is an enlarged detailed view of part A in FIG. 4. [Figure 6] FIG. 10 is a cutaway side view showing a state in which the second transfer unit is lowered until a gap is formed between the plate and the wafer. [Figure 7] This is a broken side view showing a state in which a water layer is formed between the underside of the plate of the second transport unit and the polished surface of the wafer, and a gas-liquid mixed layer is formed between the holding surface of the chuck table and the underside of the wafer. [Figure 8] FIG. 10 is a cutaway side view showing a state in which the wafer is clamped by the edge clamp mechanism of the second transfer unit and removed from the holding surface of the chuck table. DETAILED DESCRIPTION OF THE INVENTION

[0010] [Polishing equipment configuration] The polishing apparatus 1 shown in Figure 1 is an apparatus for polishing a circular wafer, which is the workpiece to be polished, and is equipped with a chuck table 10 that holds the wafer on a holding surface 11, a processing unit 30 that polishes the wafer 100 held on the holding surface 11 of the chuck table 10, a cleaning unit 50 that cleans the top surface (surface to be polished) of the wafer, a first transport unit 61 and a second transport unit 62 that transport the wafer 100, and a control unit 90.

[0011] The wafer 100 shown in Fig. 2 is made of a single-crystal silicon base material, and has a plurality of devices (not shown) formed on a surface 103 facing downward in the state shown in Fig. 2. The surface 103 side of the wafer 100 is held by suction on the holding surface 11 of the chuck table 10, and the back surface 104 is ground to a predetermined thickness by a grinding process, which is a pre-process of the polishing process.

[0012] Specifically, as shown in FIG. 2, the peripheral portion of the back surface 104 of the wafer 100, which corresponds to the area where devices are not formed, is not ground, and only the central portion, which corresponds to the area where devices are formed, is ground by a grinding wheel (not shown). As a result, a circular recess 101 is formed in the central portion of the back surface 104 of the ground wafer 100, and a ring-shaped protrusion, which maintains its original thickness, is formed on the outer periphery of this recess 101 as a reinforcing portion 102. The wafer 100 thus formed with the ring-shaped reinforcing portion 102 around the central circular recess 101 has increased rigidity due to the reinforcing portion 102, making it easier to handle thereafter. Note that the wafer to be polished by the polishing apparatus 1 is not limited to the wafer 100 shown in FIG. 2, and may be a wafer with a flat back surface.

[0013] 1 and 4, the chuck table 10 is a disk-shaped member, and a disk-shaped porous member 13 made of porous ceramic or the like is incorporated into a circular recess 12 formed in the center thereof. The upper surface of the porous member 13 forms a holding surface 11 that suction-holds the disk-shaped wafer 100.

[0014] 4 to 7, a suction source 14 such as a vacuum pump, an air supply source 15 such as an air compressor, and a water supply source 16 such as a water pump are connected to the porous member 13. Specifically, a pipe 17 is connected to the porous member 13, and a vacuum pipe 18, an air pipe 19, and a water pipe 20 branch off from the pipe 17. The suction source 14 is connected to the vacuum pipe 18 via a variable orifice 21 and an electromagnetic on-off valve 22. The air pipe 19 is connected to the air supply source 15 via a variable orifice 23 and an electromagnetic on-off valve 24. The water pipe 20 is connected to the water supply source 16 via a variable orifice 25 and an electromagnetic on-off valve 26. The three electromagnetic on-off valves 22, 24, and 26 are electrically connected to a control unit 90 shown in FIG. 1, and their opening and closing is controlled by the control unit 90.

[0015] The chuck table 10 is rotated at a predetermined speed around its vertical central axis by a rotation drive mechanism including a motor (not shown) disposed below the chuck table 10. The motor (not shown) is electrically connected to the control unit 90 shown in FIG. 1, and its drive is controlled by the control unit 90.

[0016] As shown in Fig. 1, the polishing apparatus 1 has a rectangular box-shaped base 2 that is long in the Y-axis direction (front-rear direction), and a rectangular block-shaped internal base 3 is housed inside the base 2. A horizontal movement mechanism 4 is provided on the internal base 3 for moving a chuck table 10 along the Y-axis direction (front-rear direction). The horizontal movement mechanism 4 has a block-shaped slider 5, and the slider 5 is slidable in the Y-axis direction along a pair of left and right guide rails 6 that are arranged parallel to each other along the Y-axis direction (front-rear direction). Therefore, the chuck table 10 supported by the slider 5 and a rotation drive mechanism (not shown) that rotationally drives the chuck table 10 are slidable along the Y-axis direction together with the slider 5.

[0017] A rotatable ball screw shaft 7 extending in the Y-axis direction (front-rear direction) is disposed between a pair of left and right guide rails 6 on the internal base 3, and one end of the ball screw shaft 7 in the Y-axis direction (the left end in FIG. 1) is connected to a motor 8, which serves as a drive source and can rotate forward and backward. The other end of the ball screw shaft 7 in the Y-axis direction (the right end in FIG. 1) is rotatably supported by a bearing 9 erected on the internal base 3. A nut member (not shown) protruding downward from the slider 5 is threadedly inserted and fitted onto the ball screw shaft 7. The motor 8 is electrically connected to a control unit 90, and its drive is controlled by the control unit 90.

[0018] Therefore, when the ball screw shaft 7 is rotated forward or backward by the motor 8, a nut member (not shown) threadedly inserted into the ball screw shaft 7 slides in the Y-axis direction (front-back direction) along the ball screw shaft 7 together with the slider 5, and the chuck table 10 also moves integrally along the Y-axis direction together with the slider 5. As a result, the wafer 100, which is the object to be polished and held by suction on the holding surface 11 of the chuck table 10, also moves along the Y-axis direction.

[0019] 1, a rectangular opening 27 that is long in the Y-axis direction is formed in the upper surface of the base 2, and the chuck table 10 is disposed in this opening 27 so as to be movable in the Y-axis direction. The periphery of the chuck table 10 at opening 27 that opens in the upper surface of the base 2 is covered with a rectangular plate-shaped cover 28, and the front and rear portions (-Y direction and +Y direction) of cover 28 of opening 27 are covered by bellows-shaped expandable covers 29 that expand and contract together with cover 28. Therefore, no matter where chuck table 10 is in the Y-axis direction, opening 27 is covered by expandable cover 29, and foreign matter is prevented from entering the inside of base 2 through opening 27.

[0020] The processing unit (polishing mechanism) 30 that polishes the back surface 104 of the wafer 100 includes a spindle 31 having a rotation center axis in the Z-axis direction, a housing 32 that rotatably supports the spindle 31, a spindle motor 33 that rotationally drives the spindle 31, a mount 34 connected to the lower end of the spindle 31, and a disc-shaped polishing pad 35 that is detachably attached to the lower surface of the mount 34. The polishing pad 35 is configured by adhering a disc-shaped pad material 352 such as nonwoven fabric or urethane to the lower surface of a disc-shaped base 351. The spindle motor 33 is electrically connected to the control unit 90, and its driving is controlled by the control unit 90.

[0021] 1, a column 36 is erected on the end (rear end) in the +Y-axis direction of the upper surface of the base 2, and an elevating mechanism 40 is provided on the end (front) of the column 36 in the -Y-axis direction. The elevating mechanism 40 raises and lowers the machining unit 30 in a direction perpendicular to the holding surface 11 of the chuck table 10 (the Z-axis direction), and raises and lowers a rectangular plate-shaped elevating plate 41 attached to the back surface of the housing 32 and a holder 45 attached to the elevating plate 41 and supporting the housing 32, along a pair of left and right guide rails 42 in the Z-axis direction, together with the housing 32, the spindle 31, the spindle motor 33, the polishing pad 35, and the like held by the housing 32. The pair of left and right guide rails 42 are disposed perpendicular to the front surface of the column 36 and parallel to each other.

[0022] 1, a rotatable ball screw shaft 43 is erected along the Z-axis direction (vertical direction) between a pair of left and right guide rails 42, and the upper end of the ball screw shaft 43 is connected to a motor 44 that can rotate forward and backward and serves as a drive source. The lower end of the ball screw shaft 43 is rotatably supported on the column 36 by a bearing (not shown), and a nut member (not shown) that protrudes horizontally backward (in the +Y-axis direction) from the back surface of the lifting plate 41 is threadedly inserted into the ball screw shaft 43. The motor 44 is electrically connected to a control unit 90, and its drive is controlled by the control unit 90.

[0023] The cleaning unit 50 cleans the wafer 100 polished by the processing unit 30 to remove slurry and processing debris adhering to the polished surface, and is equipped with a spinner table 51 that holds and rotates the wafer 100 after polishing, and an injection nozzle 52 that injects cleaning water or high-pressure air toward the polished surface of the wafer 100.

[0024] 1, a cassette 111 for storing a plurality of wafers 100 before polishing and a cassette 112 for storing wafers 100 after polishing are disposed at the front end side (the end in the -Y axis direction) of the base 2. A carry-in / out unit 114 for carrying the wafers 100 into and out of the cassettes 111 and 112 is disposed at the +Y direction side of the cassettes 111 and 112. The carry-in / out unit 114 includes a holder 115 for holding the wafers 100, an inversion drive unit 116 for rotating the holder 115 about a horizontal axis to invert the holder 115, an arm unit 117 for rotating the holder 115 and the inversion drive unit 116, and an elevation drive unit 118 for raising and lowering the holder 115, the inversion drive unit 116, and the arm unit 117.

[0025] An alignment unit 113 is disposed within the movable range of the holder 115 of the carry-in / out unit 114. The alignment unit 113 includes an alignment table 119 on which the wafer 100 is placed, and a plurality of alignment pins 120 that are movable in the radial direction of the alignment table 119. With the wafer 100 placed on the alignment table 119, the alignment pins 120 move in directions approaching each other, thereby aligning the wafer 100 to a fixed position.

[0026] A first transfer unit 61 is disposed near the alignment unit 113 to transfer the wafer 100 from the alignment unit 113 to the chuck table 10. The first transfer unit 61 includes a holder 611 that holds the wafer 100 by suction, an arm 612 that rotates the holder 611, and an elevation drive unit 613 that raises and lowers the holder 611 and the arm 612.

[0027] On the −X direction side of the first transfer unit 61, a second transfer unit 62 is disposed to transfer the polished wafer 100 to the cleaning unit 50. The configuration of the second transport unit 62 will be described in detail below with reference to FIGS.

[0028] The second transport unit 62 includes a transport pad 64 attached to the tip of the horizontal part 631 of a liftable and rotatable arm 63, and a movement mechanism 65 (see Figure 4) that moves the transport pad 64 up and down (in the Z-axis direction) together with the arm 63.

[0029] 3, the transport pad 64 is a member that horizontally supports the wafer 100 by an edge clamp mechanism, and includes a disk-shaped plate 66, pin-shaped claw members 67 (only one of which is shown in FIG. 3) that are inserted vertically and supported at equal angular pitches (120° pitches) at three locations around the outer periphery of the plate 66, and a horizontal movement mechanism 68 that moves the claw members 67 horizontally along the radial direction of the plate 66. The plate 66 may be formed in a rectangular shape. The number of the claw members 67 is not limited to three, as long as there are three or more. Also, the pitch does not have to be equal.

[0030] 3, a circular mounting portion 632 is formed at the tip of a horizontal portion 631 of arm 63, and plate 66 is mounted horizontally to mounting portion 632 of arm 63 by bolts 69 inserted vertically at three circumferential positions of mounting portion 632 at equal angular pitches (120° pitches). A circular rotating plate 70 is disposed on the upper surface side of plate 66, and arc-shaped elongated holes 71 are formed in three circumferential positions of rotating plate 70 at equal angular pitches (120° pitches) in the circumferential direction. Furthermore, a circular hole 72 is formed in the center of rotating plate 70, as shown in FIG.

[0031] The bolts 69 are inserted through three elongated holes 71 formed in the rotating plate 70. Therefore, the rotating plate 70 can rotate about its axis within an angular range that allows the bolts 69 to slide relatively within the elongated holes 71. Arm portions 701 (only one is shown in FIG. 3 ) are integrally provided on three circumferential positions of the outer periphery of the rotating plate 70 so as to protrude radially outward at equal angular intervals (120° pitches) in the circumferential direction. The arm portions 701 protruding from the outer periphery of the rotating plate 70 and the upper ends of the claw members 67 that protrude above the plate 66 are connected to each other by links 73, and one end of each link 73 is rotatably attached to the arm portion 701 by a pin 74. Here, linear elongated holes 75 (see FIG. 4) that are long in the radial direction are formed at three circumferential positions of the plate 66 where the claw members 67 are provided, and each claw member 67 is inserted into each elongated hole 75. Therefore, each claw member 67 can move horizontally in the radial direction of the plate 66 (in the direction of approaching and separating from each other) within a range in which it can slide within each elongated hole 75.

[0032] 3, a connecting arm 702 is integrally provided to protrude radially outward from one location on the outer periphery of the rotating plate 70, and the tip of a piston rod 761 extending from an air cylinder 76 serving as an actuator installed on the plate 66 is connected to this connecting arm 702. Note that when compressed air is supplied to or discharged from the air cylinder 76, the piston rod 761 moves back and forth linearly, thereby rotating the rotating plate 70. Note that the supply and discharge of compressed air to and from the air cylinder 76 is controlled by the control unit 90 shown in FIG.

[0033] Here, the rotating plate 70, air cylinder 76, and link 73 constitute a horizontal movement mechanism that moves each claw member 67 horizontally in the radial direction of the plate 66 along the elongated holes 75 formed in the plate 66, and this horizontal movement mechanism and the three claw members 67 constitute an edge clamp mechanism that grips and holds the outer periphery and underside (edge ​​portion) of the wafer 100 with claws 671 at their tips (lower ends). The claw members 67 are made of a resin with a small coefficient of friction, such as a fluororesin, and the plate 66 is made of a highly hydrophilic material, such as titanium oxide, glass, or aluminum.

[0034] 4 and 5, a concave water channel 77 is formed in the lower part of the portion of the plate 66 surrounded by the three claw members 67, and a plurality (a large number) of water injection passages 78 extending vertically are formed in an orderly manner (at equal angular pitch on the same circumference) in this water channel 77. These water injection passages 78 each open to the underside of the plate 66 as a water injection port 781 (see FIG. 5).

[0035] 4, a water passage 79 formed in the vertical direction in the center of the plate 66 communicates with the water channel 77 formed in the lower part of the plate 66, and one end (lower end) of a water pipe 80 extending vertically is connected to this water passage 79, which penetrates an annular mounting portion 632 formed at the tip of the arm 63 and a circular hole 72 formed in the center of the rotating plate 70. The other end of the water pipe 80 is connected to a water supply source 82 via an electromagnetic on-off valve 81. The electromagnetic on-off valve 81 is electrically connected to the control unit 90 shown in FIG. 1, and its opening and closing operation is controlled by the control unit 90.

[0036] The transport pad 64 configured as above can be moved up and down together with the arm 63 in the vertical direction (Z-axis direction) by the movement mechanism 65 shown in FIG. 4, and this movement mechanism 65 is configured as follows.

[0037] 1, and includes a guide rail 84 and a ball screw shaft 85 that are arranged along the vertical surface of an upright column 83. The upper end of the ball screw shaft 85 is rotatably supported by a bearing 86 fixed to the column 83, and a motor 87 and an encoder 88, which serve as a drive source, are attached to the lower end of the ball screw shaft 85.

[0038] A nut member 89 attached to the arm 63 is threadedly inserted onto the ball screw shaft 85. Therefore, when the motor 87 is driven to rotate the ball screw shaft 85 forward or backward, the nut member 89 threaded onto the ball screw shaft 85 and the arm 63 move up and down in the vertical direction (Z-axis direction) together with the transport pad 64. The motor 87 and the encoder 88 are electrically connected to a control unit 90 shown in FIG. 1, and the rotation direction, rotation speed, rotation angle, etc. of the motor 87 detected by the encoder 88 are transmitted to the control unit 90 as detection signals, and the control unit 90 controls the driving of the motor 87 based on these detection signals.

[0039] The control unit 90 includes a CPU (Central Processing Unit) that performs arithmetic processing according to a control program, and memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory).

[0040] [Actions and effects of the polishing equipment] Next, the polishing of the wafer 100 by the polishing apparatus 1 configured as above will be described.

[0041] When polishing the wafer 100, the wafer 100 is placed with its surface 103 facing downward on the holding surface 11 of the chuck table 10. Then, when the control unit 90 opens the electromagnetic on-off valve 22 shown in Fig. 4 and evacuates the porous member 13 with the suction source 14, a negative pressure is generated in the porous member 13, and the wafer 100 placed on the upper surface (holding surface 11) of the porous member 13 is sucked and held on the holding surface 11 by the negative pressure, as shown in Fig. 4. At this time, the other electromagnetic on-off valves 24 and 26 are both closed.

[0042] 1 to move the chuck table 10 in the +Y-axis direction (rearward), and position the wafer 100, which is suction-held on the chuck table 10, below the polishing pad 35 of the processing unit 30. That is, when the motor 8 is started and the ball screw shaft 7 rotates, the slider 5, to which a nut member (not shown) that is threadably inserted onto the ball screw shaft 7 is attached, slides in the +Y-axis direction along the pair of left and right guide rails 6 together with the chuck table 10 and the like, and the wafer 100, which is held on the holding surface 11 of the chuck table 10, is positioned below the polishing pad 35 of the processing unit 30.

[0043] The control unit 90 also drives a rotation drive mechanism (not shown) to rotate the chuck table 10 at a predetermined rotation speed (e.g., 300 rpm), and simultaneously starts the spindle motor 33 of the processing unit 30 to rotate the polishing pad 35 at a predetermined speed (e.g., 1000 rpm).

[0044] As described above, while the wafer 100 and polishing pad 35 are rotating, the lifting mechanism 40 is driven to lower the polishing pad 35 in the −Z-axis direction. That is, when the motor 44 is driven to rotate the ball screw shaft 43, the lifting plate 41 and holder 45, which are provided with a nut member (not shown) that threadably fits onto the ball screw shaft 43, are lowered in the −Z-axis direction together with the housing 32 and the polishing pad 35. As a result, the lower surface (polishing surface) of the polishing pad 35 comes into contact with the back surface 104 of the wafer 100. At this time, slurry is supplied from a slurry supply source (not shown) to the contact surface between the polishing pad 35 and the wafer 100. As a result, the chemical action of the slurry and the mechanical action of the polishing pad 35 work together to polish the bottom surface of the recess 101 of the wafer 100.

[0045] After the wafer 100 is polished by the polishing pad 35 in the processing unit 30, the chuck table 10 moves in the -Y direction, and then the wafer 100 is transported from the chuck table 10 to the cleaning unit 50 by the second transport unit 62.This process is explained below with reference to Figures 4 to 8.

[0046] The control unit 90 rotates the arm 63 of the second transfer unit 62, and as shown in Fig. 4, the transfer pad 64 supported on the tip of the arm 63 is positioned above the wafer 100 held by suction on the holding surface 11 of the chuck table 10. Then, from the state shown in Fig. 4, the control unit 90 drives the motor 87 of the movement mechanism 65 to rotate the ball screw shaft 85, and moves the arm 63 and the transfer pad 64 downward (in the -Z axis direction). At this time, the claws 671 at the tips (lower ends) of the claw members 67 provided at three locations circumferentially on the outer periphery of the plate 66 are arranged to surround the outer periphery of the wafer 100 from the outside.

[0047] 6, when a gap δ1 shown in Fig. 6 is formed between the polished surface of the wafer 100 and the underside of the plate 66 of the transfer pad 64, the control unit 90 opens the electromagnetic on-off valve 81 to supply water from the water supply source 82 through the water piping 80 to the water passage 79 formed in the center of the plate 66 of the transfer pad 64, and opens the electromagnetic on-off valves 24 and 26 to supply air from the air supply source 15 and water from the water supply source 16 through the piping 17 to the porous member 13. At this time, the electromagnetic on-off valve 22 is closed.

[0048] As described above, when air and water are supplied to the porous member 13 from the air supply source 15 and the water supply source 16, respectively, a mixed fluid of air and water is ejected from the holding surface 11 of the porous member 13, forming a gap δ2 between the holding surface 11 and the surface 103 of the wafer 100. A mixed liquid layer 92 is formed in this gap δ2. This mixed liquid layer 92 causes the wafer 100 to float from the holding surface 11 of the chuck table 10, and the wafer 100 is released from the holding surface 11. Then, the claw members 67 are moved toward each other to support the outer edge of the wafer 100, and the claws 671 of the claw members 67 are inserted into the underside of the wafer 100 to support the underside of the wafer 100. In addition, the air bubbles contained in the mixed liquid layer 92 weaken the surface tension of the water, making it easier for the wafer 100 to be released from the mixed liquid layer 92. When the gap δ 2 is formed, a gap δ 3 is formed between the polished surface of the wafer 100 and the lower surface of the plate 66 of the transfer pad 64 .

[0049] When water is supplied from the water supply source 82 to the water passage 79 formed in the center of the plate 66, the water passes through the water channel 77 formed in the lower part of the plate 66 and flows through the multiple water injection passages 78 shown in Figure 5, and a water layer 91 is formed in the gap δ3 between the polished surface of the wafer 100 and the lower surface of the plate 66 so as to apply pressure evenly over the entire polished surface of the wafer 100 from each water injection port 781 opening on the lower surface of the plate 66.

[0050] Even if bubbles contained in the mixed liquid layer 92 formed in the gap δ2 between the holding surface 11 of the chuck table 10 and the surface 103 of the wafer 100 burst at the outer peripheral edge of the wafer 100, a water layer is formed over the entire polished surface of the wafer 100 by water supplied from multiple water injection ports 781 (see FIG. 5 ) opening on the underside of the plate 66. This water layer applies uniform downward pressure to the polished surface of the wafer 100. Therefore, even if bubbles burst in the mixed liquid layer 92, the wafer 100 does not flap and remains horizontal without tilting. Furthermore, the claw members 67 restrict the horizontal movement of the wafer 100. In this state, the transfer pad 64 is raised to remove the wafer 100 from the mixed liquid layer 92. Once the wafer 100 is removed from the mixed liquid layer 92, the water supply from the water injection ports 781 may be stopped. It should be noted that the water supply from the water injection port 781 may be stopped immediately after the water layer 91 is formed in the gap δ3.

[0051] Next, the control unit 90 drives the air cylinder 76 shown in Figure 3 to extend the piston rod 761 of the air cylinder 76, and the rotating plate 70 to which the tip of this piston rod 761 is connected rotates in the direction of arrow 700 in Figure 3, so that each claw member 67 moves radially inward (in the direction of arrow 670 in Figure 3) along the long hole 75 via the link 73, and as shown in Figure 7, the claws 671 at the tip (lower end) of each claw member 67 engage with the outer edge and surface 103 of the wafer 100, and the wafer 100 is held horizontally with its outer edge (edge ​​portion) clamped by the three claws 671.

[0052] From the above state, when the control unit 90 drives the motor 87 of the moving mechanism 65 to reverse the ball screw shaft 85 as shown in FIG. 8, the arm 63 and the transport pad 64 supported thereby rise while holding the wafer 100 horizontally, so that the wafer 100 is released from the holding surface 11 of the chuck table 10, and the arm 63 rotates, thereby transporting the wafer 100 to the cleaning unit 50 shown in FIG. 1.

[0053] The wafer 100 transported to the cleaning unit 50 is then placed on the spinner table 51, which rotates at a predetermined speed. Cleaning water is sprayed from the spray nozzles 52 toward the rotating wafer 100, and the polished surface of the wafer 100 is cleaned with the cleaning water. Because a water layer 91 is formed on the polished surface of the wafer 100 transported to the cleaning unit 50 by the second transport unit 62, the slurry adhering to the polished surface of the wafer 100 does not dry and can be easily removed by the cleaning unit 50. After cleaning is completed in this manner, the wafer 100 is transported from the spinner table 51 to the cassette 112 by the carry-in / out unit 114 and stored therein, completing the series of polishing processes for the wafer 100.

[0054] As described above, in the polishing apparatus 1, even if bubbles contained in the mixed liquid layer 92 formed in the gap δ2 between the holding surface 11 of the chuck table 10 and the surface 103 of the wafer 100 burst at the outer peripheral edge of the wafer 100, the water layer 91 is formed over the entire polished surface of the wafer 100 by water supplied from the multiple water injection ports 781 opening on the underside of the plate 66, and this water layer 91 applies uniform downward pressure to the polished surface of the wafer 100. Therefore, even if bubbles burst in the mixed liquid layer 92, the wafer 100 does not flap and remains horizontal without tilting. Therefore, the wafer 100 can be transported to the cleaning unit 50 with the water layer 91 formed on its upper surface. Therefore, the slurry adhering to the polished surface of the wafer 100 during polishing does not dry out during transport to the cleaning unit 50, and the slurry adhering to the polished surface of the wafer 100 is easily and reliably removed by the cleaning unit 50. The gap δ2 may be formed by jetting only water from the holding surface 11. In this case, after the gap δ2 is formed, water is supplied from the multiple water jetting ports 781 to form a water layer, and then the transfer pad 64 is raised while jetting only air from the holding surface 11, so that the surface tension of the water is broken by the air, thereby separating the wafer 100 from the holding surface 11.

[0055] Furthermore, the wafer 100 is transported to the cleaning unit 50 while its outer periphery and the edge of its surface 103 are clamped and held by the claws 671 of the three claw members 67. This prevents the claws 671 from coming into contact with devices formed on the surface 103 of the wafer 100 during transport, and allows the wafer 100 to be transported to the cleaning unit 50 without damaging the devices. The wafer 100 is not limited to one having a recess formed in the center, but may be a bonded wafer in which a wafer on which a device is formed is bonded to a support substrate.

[0056] Although the above description has been given of an embodiment in which the present invention is applied to a polishing apparatus as one form of processing apparatus, the present invention can also be applied to any other processing apparatus such as a grinding apparatus other than a polishing apparatus.

[0057] Furthermore, the present invention is not limited to the application of the above-described embodiments, and it goes without saying that various modifications are possible within the scope of the technical ideas described in the claims. [Explanation of symbols]

[0058] 1: Polishing device (processing device), 2: Base, 3: Internal base, 4: Horizontal movement mechanism, 5: Slider, 6: Guide rail, 7: Ball screw shaft, 8: Motor, 9: Bearing, 10: chuck table, 11: holding surface, 12: recess, 13: porous member, 14: suction source, 15: air supply source, 16: water supply source, 17: piping, 18: vacuum piping, 19: Air piping, 20: Water piping, 21: Variable orifice, 22: Solenoid valve, 23: variable orifice, 24: electromagnetic on-off valve, 25: variable orifice, 26: electromagnetic on-off valve, 27: Opening, 28: Cover, 29: Telescopic cover, 30: Processing unit, 31: spindle, 32: housing, 33: spindle motor, 34: mount, 35: polishing pad, 351: base, 352: pad material, 36: column, 40: lifting mechanism, 41: lifting plate, 42: guide rail, 43: ball screw shaft, 44: motor, 50: cleaning unit, 51: spinner table, 52: spray nozzle, 60: transport unit, 61: first transport unit, 62: second transport unit, 63: Arm, 631: horizontal part of arm, 632: mounting part of arm, 64: transport pad, 65: moving mechanism, 66: plate, 67: claw member, 671: claw, 68: horizontal moving mechanism, 69: Bolt, 70: Rotating plate, 701: Arm portion of the rotating plate, 702: connecting arm of rotating plate, 71: oblong hole, 72: circular hole, 73: link, 74: Pin, 75: Slot, 76: Air cylinder, 761: Piston rod, 77: Water channel, 78: Water injection passage, 781: Water injection port, 79: Water passage, 80: Water piping, 81: electromagnetic on-off valve, 82: water supply source, 83: column, 84: guide rail, 85: ball screw shaft, 86: bearing, 87: motor, 89: nut member, 90: control section, 91: water layer, 92: mixed liquid layer, 100: wafer, 101: Wafer recess, 102: Wafer reinforcement, 111, 112: Cassette, 113: Alignment table, 114: Loading / unloading unit, δ1, δ2, δ3: gap

Claims

1. A processing apparatus for processing a wafer held on a holding surface, the wafer holding apparatus includes a chuck table that holds a wafer on the holding surface, a processing unit that processes the wafer held on the holding surface, a cleaning unit that cleans the upper surface of the wafer, a transport unit that transports the wafer, and a control unit; The transfer unit includes a transfer pad for holding a wafer and a moving mechanism for moving the transfer pad; The transport pad includes a plate on which at least three claws are arranged at intervals in the circumferential direction of the wafer to be held, a horizontal movement mechanism for horizontally moving the claws in a direction parallel to the lower surface of the plate, and a plurality of water injection ports that open on the lower surface of the portion of the plate surrounded by the claws and inject water so as to apply uniform pressure to the processed surface of the wafer processed by the processing unit, the control unit moves the transport pad so that a gap is formed between the processing surface of the wafer held by the holding surface and the lower surface of the plate, and the claws surround the outer periphery of the wafer; a mixed fluid of water and air is ejected from the holding surface to form a mixed liquid layer between the holding surface and the lower surface of the wafer, and water is ejected from the water ejection port of the plate to form a water layer between the processed surface of the wafer and the lower surface of the plate; The claws surrounding the outer periphery of the wafer are moved in a direction approaching each other, and the claws support the outer periphery and the lower surface of the wafer; maintaining the water layer formed on the processed surface of the wafer and transporting the wafer supported by the claws to the cleaning unit.

2. 2. The processing apparatus according to claim 1, wherein the surface of the wafer to be processed is the bottom surface of a circular recess formed in the center of the wafer.

3. 3. The processing apparatus according to claim 1, wherein the claws are arranged on the plate so as to be movable up and down in a direction perpendicular to the holding surface.

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