Transport device

Abstract

To prevent damage to a wafer during transportation.SOLUTION: In an unloading mechanism 172, a fifth control unit 75 of a control unit 7 opens a release valve 92 to communicate a closed chamber 200 with a partial suction path 921, which is under negative pressure, to make the internal pressure of the closed chamber 200 weakly negative, and a wafer 100 is sucked and held by a suction surface 801. Therefore, in the unloading mechanism 172, the internal pressure of the closed chamber 200 can be easily set to a weakly negative pressure. This makes it possible to prevent a strong force from being applied to the wafer 100 when the wafer 100 is held by the suction pad 80. Therefore, it becomes possible to prevent damage to the wafer 100 during transportation by the unloading mechanism 172.SELECTED DRAWING: Figure 7

Description

[Technical field]

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

[0002] As disclosed in Patent Document 1, in the TAIKO grinding machine that grinds the center of the wafer, water is stored in the recess of the ground wafer to hold the outer periphery of the wafer, and the wafer is transported to a spinner cleaning unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-004658 A [Patent Document 2] JP 2022-135901 A Summary of the Invention [Problem to be solved by the invention]

[0004] During the above-mentioned wafer transport, the weight of the water stored in the recess may cause the recess to sag, resulting in a crack at the boundary between the ring-shaped protrusion and the recess.

[0005] As a countermeasure, the technique disclosed in Patent Document 2 covers the recessed portion with a suction pad that is in contact with the upper surface of the protruding portion and connects the suction pad to a suction source to prevent the recessed portion from sagging.

[0006] However, with this technique, it is difficult to adjust the suction force applied to the recessed portion, and if the suction force is too strong, the bottom surface of the recessed portion may be lifted up, causing cracks at the boundary between the ring-shaped protrusion and the recessed portion.

[0007] Therefore, an object of the present invention is to suppress damage to wafers during transportation. [Means for solving the problem]

[0008] The transport device of the present invention (the transport device) is a transport device for transporting a wafer, comprising a suction pad that sucks and holds the upper side of a wafer by means of a suction surface, and a moving mechanism that moves the suction pad, wherein the suction pad comprises a ring-shaped seal portion arranged on the outer periphery of the suction surface, and a suction port formed on the suction surface and connected to a suction source, and further comprises a suction path connecting the suction port and the suction source, a branch portion arranged on the suction path, a water supply path connecting the branch portion and a water supply source, a water supply valve arranged on the water supply path, a suction valve arranged between the branch portion in the suction path and the suction source, a release valve arranged in the suction path between the branch portion and the suction valve, and a control unit, wherein the control unit controls the temperature in the suction path and the a fourth control unit for controlling the time for which the suction valve is opened to set the difference between the internal pressure in the suction path between the suction valve and the release valve and the atmospheric pressure to a first negative pressure value lower than the negative pressure value generated by the suction source; a fifth control unit for controlling the time for which the release valve is opened to set the difference between the internal pressure in a closed chamber formed by the inner surface of the seal portion in contact with the upper surface of the wafer, the suction surface, and the upper surface of the wafer and the atmospheric pressure to a second negative pressure value weaker than the first negative pressure value, thereby suctioning and holding the wafer on the suction surface; and a sixth control unit for controlling the moving mechanism to move the suction pad to transport the wafer.

[0009] In this conveying device, the suction pad may be provided with an opening formed on the suction surface and a check valve connecting the opening to the atmosphere, the check valve being configured to close when the opening side is under negative pressure and to open when the opening side is under positive pressure.

[0010] The transport device may further include a shock absorber filled with air and capable of communicating with the sealed chamber formed by the inner surface of the seal portion, the upper surface of the wafer, and the suction surface. Effect of the Invention

[0011] In this transfer device, the fifth control unit of the control unit opens the release valve to communicate the closed chamber surrounded by the inner surface of the seal unit, the suction surface, and the top surface of the wafer with the portion of the suction path that is under negative pressure, between the suction valve and the release valve, thereby making the internal pressure of the closed chamber negative and suctioning and holding the wafer by the suction surface. That is, after making the portion of the suction path between the release valve and the suction valve a negative pressure (first negative pressure value) like a suction tank, the negative pressure of this portion is used to make the closed chamber a weak negative pressure (second negative pressure value), thereby suctioning and holding the wafer by the suction pad.

[0012] In this manner, the internal pressure of the closed chamber of the transfer device can be easily set to a weak negative pressure. This makes it possible to prevent the center of the wafer from sagging when the wafer is held by the suction pad, and also to prevent a strong force from being applied to the wafer. This makes it possible to prevent damage to the wafer caused by the center of the wafer being pushed up by atmospheric pressure during transfer. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a perspective view showing a configuration of a grinding device. [Diagram 2] FIG. 4 is a cross-sectional view showing a configuration of a discharge mechanism. [Diagram 3] FIG. 3(a) is a perspective view showing the configuration of the ejection mechanism, and FIG. 3(b) is a perspective view showing the suction pad from the bottom side. [Figure 4] 11 is a cross-sectional view showing a wafer transport operation by a carry-out mechanism. FIG. [Diagram 5] 11 is a cross-sectional view showing a wafer transport operation by a carry-out mechanism. FIG. [Figure 6] 11 is a cross-sectional view showing a wafer transport operation by a carry-out mechanism. FIG. [Figure 7] 11 is a cross-sectional view showing a wafer transport operation by a carry-out mechanism. FIG. [Figure 8] 11 is a cross-sectional view showing a wafer transport operation by a carry-out mechanism. FIG. [Figure 9] FIG. 2 is a cross-sectional view showing a wafer ground by TAIKO. [Figure 10] 11 is a cross-sectional view showing a wafer transport operation by a carry-out mechanism. FIG. [Figure 11] 11 is a cross-sectional view showing a wafer transport operation by a carry-out mechanism. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] As shown in Fig. 1, the grinding apparatus 1 is an example of a processing apparatus equipped with the transfer apparatus according to the present embodiment, and is an apparatus for grinding a wafer 100. The wafer 100 is an example of a plate-shaped workpiece, and has a front surface 101 and a back surface 102. The back surface 102 of the wafer 100 becomes the surface to be ground. A protective tape 103 is attached to the front surface 101.

[0015] Here, a brief description will be given of the grinding apparatus 1. In the grinding apparatus 1, the wafers 100 accommodated in the cassettes 161 / 163 on the first equipment base 10 are transported by the robot 155 to the temporary placement mechanism 152 and aligned. Thereafter, the wafers 100 temporarily placed on the temporary placement mechanism 152 are transported by the carry-in mechanism 170 to the chuck table 20 provided on the second equipment base 11 and held on its holding surface 22.

[0016] Furthermore, the wafer 100 held on the holding surface 22 is ground by a grinding mechanism 70 which is raised and lowered by a grinding feed mechanism 60 provided on a column 15. At this time, the thickness of the wafer 100 is measured by a thickness measuring device 67.

[0017] The ground wafer 100 is removed from the chuck table 20 by a removal mechanism 172, which is an example of a transfer device according to this embodiment, and is transferred to a single-wafer spinner cleaning mechanism 156 where it is cleaned. The cleaned wafer 100 is transferred into one of the cassettes 163 by the robot 155.

[0018] In addition, 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.

[0019] 2, the chuck table 20 includes a porous member 21 and a frame 23 that houses the porous member 21 so that the upper surface of the porous member 21 is exposed. The upper surface of the porous member 21 is a holding surface 22 that suction-holds the wafer 100. The holding surface 22 is connected to a first suction source 47 to suction-hold the wafer 100. A rotation mechanism 25 for rotating the wafer 100 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.

[0020] The fluid flow mechanism 46 includes a suction groove 403 provided in the frame 23 , a suction flow passage 470 communicating with the suction groove 403 , and a suction pipe 471 communicating with the suction flow passage 470 .

[0021] The suction groove 403 is provided in the bottom surface of the recess of the frame 23 of the chuck table 20 so as to be in contact with the lower surface of the porous member 21. The suction groove 403 is formed concentrically around the center of the chuck table 20.

[0022] The suction flow passage 470 extends downward from the bottom surface of the suction groove 403 and is connected to a suction pipe 471. One end of the suction pipe 471 is connected to the suction flow passage 470. The other end of the suction pipe 471 is connected to a first suction source 47. 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 member 21 of the chuck table 20 to apply a suction force to the holding surface 22, which is the upper surface of the porous member 21.

[0023] In addition, a suction on-off valve 475 and a suction flow rate adjuster 473 are disposed in the suction pipe 471 in this order from the first suction source 47 toward the suction flow path 470. The suction on-off valve 475 switches the communication state between the suction pipe 471 and the first suction source 47. The suction flow rate adjuster 473 is, for example, a proportional control valve, and is used to adjust the suction force transmitted from the first suction source 47 to the holding surface 22 of the porous member 21 by changing the internal orifice diameter when the suction on-off valve 475 is open.

[0024] Furthermore, an air pipe 481 is connected to the suction pipe 471. The air pipe 481 is a pipe for connecting the holding surface 22 of the chuck table 20 and the air supply source .

[0025] One end of the air pipe 481 is connected to the suction flow passage 470 via the suction pipe 471. The other end of the air pipe 481 is connected to the air supply source 48. The air supply source 48 includes a compressor or the like, and is used to supply air to the holding surface 22 of the chuck table 20.

[0026] Further, an air supply on-off valve 485 and an air adjustment unit 483 are disposed in the air piping 481 in this order from the air supply source 48 toward the suction flow path 470. The air supply on-off valve 485 switches the communication state between the air piping 481 and the air supply source 48. The air adjustment unit 483 is, for example, a proportional control valve, and is used to adjust the flow rate of air sent from the air supply source 48 to the holding surface 22 by changing the internal orifice diameter when the air supply on-off valve 485 is open.

[0027] Further, a water pipe 491 is connected to the air pipe 481. The water pipe 491 is a pipe for connecting the holding surface 22 of the chuck table 20 and the first water supply source 49.

[0028] One end of the water pipe 491 is connected to the suction flow passage 470 via the air pipe 481 and the suction pipe 471. The other end of the water pipe 491 is connected to a first water supply source 49. 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.

[0029] Further, in the water piping 491, a water supply on-off valve 495 and a water adjustment unit 493 are disposed in this order from the first water supply source 49 toward the suction flow path 470. The water supply on-off valve 495 switches the communication state between the water piping 491 and the first water supply source 49. The water adjustment unit 493 is, for example, a proportional control valve, and is used to change the internal orifice diameter and adjust the flow rate of water sent from the first water supply source 49 to the holding surface 22 when the water supply on-off valve 495 is open.

[0030] In addition, suction flow rate adjustment unit 473, air adjustment unit 483, and water adjustment unit 493 may be needle valves or gate valves whose orifice diameters are manually adjusted.

[0031] Next, the configuration of the unloading mechanism 172 will be described. The unloading mechanism 172 is an example of a transport device that transports the wafer 100, and unloads the wafer 100 from the chuck table 20 using a suction pad 80. Specifically, the unloading mechanism 172 suction-holds the upper surface of the wafer 100, which is suction-held on the holding surface 22 of the chuck table 20 that is connected to the first suction source 47, using the suction pad 80, lifts the wafer 100 from the holding surface 22 that is no longer connected to the first suction source 47, and unloads the wafer 100 from the holding surface 22.

[0032] 2, the discharge mechanism 172 includes a disk-shaped suction pad 80, an arm 81 that suspends the suction pad 80 so as to be vertically movable, a rotating column 82 extending in the Z-axis direction, and a moving mechanism 50 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 moving mechanism 50 moves the rotating column 82 together with the arm 81 and the suction pad 80.

[0033] The moving mechanism 50 is a mechanism for moving the suction pad 80. The moving mechanism 50 includes a column 51 erected on the first device base 10 (see FIG. 1), a ball screw 52 provided on the column 51, a guide rail 53 arranged parallel to the ball screw 52, ​​a motor 54 for rotating the ball screw 52, ​​an encoder 57 for detecting the amount of rotation (e.g., the number of rotations and the rotation angle) of the ball screw 52, ​​and a nut 55 screwed onto the ball screw 52. A rotating column part 82 is installed on the guide rail 53 in a slidable state. The rotating column part 82 is also connected to the nut 55.

[0034] In the movement mechanism 50, the motor 54 rotates the ball screw 52 about a rotation shaft 521 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 suction pad 80 suspended by the arm 81 are moved up and down. At this time, the encoder 57 recognizes the amount of rotation of the ball screw 52 and detects the height position of the suction pad 80 that is moved up and down in the Z-axis direction based on the recognition result.

[0035] Further, the moving mechanism 50 is configured to be capable of rotating the arm 81 about a rotation shaft 821 in the Z-axis direction passing through the rotating column portion 82. In this embodiment, the arm 81 can be rotated together with the suspended suction pad 80 about the rotation shaft 821 by a rotating motor (not shown).

[0036] In this manner, in the moving mechanism 50, the arm 81 is moved up and down and rotated to move the suction pad 80, thereby making it possible to adjust the height position and horizontal position of the suction pad 80.

[0037] 2 and 3(a), an annular member 811 is attached to the end portion on the tip side of the arm 81. As shown in Fig. 2, a plurality of (e.g., three) through holes 812 are formed at equal intervals on the circumference of the annular member 811. A bolt 84 connected to the suction pad 80 is inserted into the through hole 812.

[0038] The bolt 84 includes a shaft portion 841 having a diameter slightly smaller than that of the through hole 812 , and a head portion 842 formed at the upper end of the shaft portion 841 .

[0039] The shaft portion 841 passes through the through hole 812 and is loosely fitted in the through hole 812. The lower end of the shaft portion 841 is connected to the upper surface of the base plate 90 of the suction pad 80. The head portion 842 is formed to have a larger diameter than the through hole 812, and limits the downward range of the bolt 84.

[0040] Moreover, the bolt 84 has a spring 843 as a shock absorbing member around the shaft portion 841. The upper end of the spring 843 contacts the lower surface of the circular member 811, while the lower end of the spring 843 contacts the upper surface of the base plate 90 of the suction pad 80. The spring 843 biases the circular member 811 and the suction pad 80 in directions moving away from each other.

[0041] The arm 81 is capable of suspending the suction pad 80 while absorbing impacts applied to the suction pad 80 via the circular ring member 811 and the bolt 84 thus configured.

[0042] The suction pad 80 suction-holds the back surface 102, which is the upper surface of the wafer 100 placed on the holding surface 22 of the chuck table 20. As shown in Fig. 2 and Fig. 3(b), the suction pad 80 is a disk-shaped plate, the lower surface of which serves as a suction surface 801 that suctions the wafer 100. The suction pad 80 suction-holds the back surface 102, which is the upper surface of the wafer 100, by means of the suction surface 801.

[0043] 2, a suction shaft 95 is connected to the center of the upper surface of the suction pad 80 so as to pass through the center of the annular member 811 of the arm 81. A suction path 91 is formed so as to penetrate the suction shaft 95 and the suction pad 80. The lower end of the suction path 91 is connected to a suction port 802, which is an opening formed in the center of the suction surface 801. The upper end of the suction path 91 is connected to a second suction source 94 via a release valve 92 and a suction valve 93.

[0044] Thus, in the discharge mechanism 172, the suction port 802 of the suction pad 80 is formed on the suction surface 801 and is connected to the second suction source 94. Also, the suction path 91 connects the suction port 802 and the second suction source 94. Note that a partial suction path 921, which is a portion of the suction path 91 between the release valve 92 and the suction valve 93, is provided with a differential pressure gauge 120 that measures the difference between the partial suction path 921 and the atmospheric pressure.

[0045] Moreover, a branch portion 96 is disposed between the upper end of the suction shaft 95 in the suction passage 91 and the release valve 92. The above-mentioned suction valve 93 is disposed between the branch portion 96 in the suction passage 91 and the second suction source 94. The release valve 92 is disposed between the branch portion 96 in the suction passage 91 and the suction valve 93. Therefore, in this embodiment, by opening the release valve 92 and the suction valve 93, the suction port 802 can be communicated with the second suction source 94 via the suction passage 91 and the branch portion 96.

[0046] Moreover, one end of a water supply passage 97 is connected to the branching portion 96. The other end of the water supply passage 97 is connected to a second water supply source 99 via a water supply valve 98. In this manner, the water supply passage 97 connects the branching portion 96 and the second water supply source 99, and the water supply valve 98 is disposed in the water supply passage 97.

[0047] Also, a ring-shaped seal portion 803 is provided on the outer periphery (outer periphery) of the suction surface 801 of the suction pad 80. The seal portion 803 is a portion that comes into contact with the outer periphery of the back surface 102 of the wafer 100 when the wafer 100 is transported by the unloading mechanism 172. With this seal portion 803, in the unloading mechanism 172, a closed chamber 200 (see FIG. 4) can be formed that is surrounded by an inner surface 803a of the seal portion 803 that comes into contact with the back surface 102, which is the upper surface of the wafer 100, the suction surface 801, and the back surface 102 of the wafer 100.

[0048] A first through hole 804 is formed near the outer periphery of the suction pad 80, extending through the suction pad 80. The lower end of the first through hole 804 is connected to a first opening 805, which is an outlet formed in the suction surface 801. The upper end of the first through hole 804 is connected to a check valve 85 formed on the upper surface of the suction pad 80.

[0049] This check valve 85 communicates the first opening 805 with the atmosphere through the first through hole 804. Therefore, when the closed chamber 200 is formed, the check valve 85 can communicate the closed chamber 200 with the atmosphere. The check valve 85 is configured to close when the first opening 805 side (inside the closed chamber 200) is at negative pressure (or atmospheric pressure), and to open when the first opening 805 side (inside the closed chamber 200) becomes positive pressure. Therefore, the first opening 805 and the check valve 85 can release a fluid (e.g., water) in the closed chamber 200 so that the pressure in the closed chamber 200 does not become positive pressure.

[0050] Further, the suction pad 80 is formed with a second through hole 806 extending through the suction pad 80. The lower end of the second through hole 806 is connected to a second opening 807 formed in the suction surface 801. The upper end of the second through hole 806 is connected to a shock absorber 86 provided on the upper surface of the suction pad 80. The shock absorber 86 is for reducing pressure fluctuations applied to the suction surface 801 of the arm 81 and the back surface 102 of the wafer 100. The shock absorber 86 is configured to be able to communicate with the above-mentioned closed chamber 200 via the second opening 807 and the second through hole 806. The inside of the shock absorber 86 is filled with air.

[0051] Moreover, the discharge mechanism 172 has a control unit 7 for controlling the discharge mechanism 172. The control unit 7 includes a CPU that performs calculation processing according to a control program, and a storage medium such as a memory. The control unit 7 executes various processes and comprehensively controls each component of the discharge mechanism 172. The control unit 7 may be configured to control the entire configuration of the grinding apparatus 1 including the discharge mechanism 172.

[0052] In this embodiment, the control unit 7 includes a first control unit 71, a second control unit 72, a third control unit 73, a fourth control unit 74, a fifth control unit 75 and a sixth control unit 76, and these are used to perform the transport operation of the wafer 100 by the unloading mechanism 172.

[0053] Next, a method for transporting the wafer 100 by the unloading mechanism 172 having the above configuration will be described. The transport of the wafer 100 by the unloading mechanism 172 is performed by the control unit 7 after grinding of the wafer 100 using the grinding mechanism 70 (see FIG. 1) is completed.

[0054] After grinding of the wafer 100 is completed, the chuck table 20 holding the wafer 100 is moved by a moving mechanism (not shown) from below the grinding mechanism 70 to a position on the -Y direction side closer to the unloading mechanism 172. Thereafter, the control unit 7 causes the moving mechanism 50 in the unloading mechanism 172 to pivotally move the rotating column 82 and the arm 81, as shown in Fig. 2, to position the suction pad 80 above the wafer 100 sucked and held 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 suction 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 match.

[0055] At this time, the suction on-off valve 475 of the fluid distribution mechanism 46 is open, and the holding surface 22 of the chuck table 20 is connected to the first suction source 47 to hold the wafer 100 by suction.

[0056] At this time, the first control unit 71 of the control unit 7 opens the suction valve 93, the release valve 92, and the water supply valve 98, thereby filling the suction passage 91 and the water supply passage 97 with water. That is, by opening the suction valve 93, the second suction source 94, and the water supply valve 98, the suction passage 91 is connected to the second suction source 94, creating a negative pressure, and the suction passage 91 is filled with water supplied from the water supply passage 97, which is connected to the second water supply source 99. The negative pressure value generated in the second suction source 94 at this time is, for example, -80 kPa. The pressure at which the water is supplied from the second water supply source 99 is, for example, 0.3 MPa. This also causes water to be supplied from the suction port 802 communicating with the lower end of the suction path 91 toward the back surface 102 of the wafer 100 disposed therebelow.

[0057] 4, the second control unit 72 of the control unit 7 lowers the rotating column unit 82 by the moving mechanism 50, thereby lowering the suction pad 80 suspended at the tip of the arm 81, as shown by the arrow 301. By lowering the suction pad 80 in this manner, the second control unit 72 brings the seal unit 803 into contact with the back surface 102 of the wafer 100. As a result, a closed chamber 200 is formed that is surrounded by the inner surface 803a of the seal unit 803, the suction surface 801, and the back surface 102 of the wafer 100.

[0058] Water supplied from suction port 802 is accumulated in closed chamber 200. When the water pressure in closed chamber 200 exceeds atmospheric pressure, check valve 85 opens and the water is discharged from closed chamber 200 to the outside. At this time, the measurement value of the differential pressure gauge 120, that is, the difference between the internal pressure of the partial suction path 921, which is the portion of the suction path 91 between the suction valve 93 and the release valve 92, and the atmospheric pressure, is, for example, 0 kPa.

[0059] Next, the third control unit 73 of the control unit 7 closes the suction valve 93, the release valve 92, and the water supply valve 98 in this order, as shown in Fig. 5. This keeps the partial suction path 921 of the suction path 91 filled with water.

[0060] Then, as shown in FIG. 6, the fourth control unit 74 of the control unit 7 controls the time for which the suction valve 93 is opened, and sets the difference between the internal pressure of the partial suction path 921 in the suction path 91 and the atmospheric pressure to a first negative pressure value that is less than or equal to the negative pressure value generated by the second suction source 94. That is, the fourth control unit 74 opens the suction valve 93 and measures the difference between the internal pressure of the partial suction path 921 and the atmospheric pressure using the differential pressure gauge 120. Then, the fourth control unit 74 closes the suction valve 93 when the measurement value of the differential pressure gauge 120 becomes a first negative pressure value. This first negative pressure value is, for example, a value equal to or greater than -80 kPa and less than -1 kPa. In this case, the internal pressure of the partial suction path 921 becomes a pressure that is lower than the atmospheric pressure by more than 1 kPa and not more than 80 kPa.

[0061] Next, as shown in FIG. 7, the fifth control unit 75 of the control unit 7 controls the time for opening the release valve 92 to set the difference between the internal pressure of the sealed chamber 200 formed by the inner surface of the seal portion 803 of the suction pad 80 in contact with the back surface 102 of the wafer 100, the suction surface 801, and the back surface 102 of the wafer 100 and the atmospheric pressure to a second negative pressure value that is weaker than the first negative pressure value, thereby suction-holding the wafer 100 by the suction surface 801. That is, the fifth control unit 75 opens the release valve 92 to communicate the closed chamber 200 with the partial suction path 921, which is at a negative pressure. As a result, the internal pressure of the closed chamber 200 becomes negative, and the wafer 100 is sucked and held by the suction pad 80 (suction surface 801). Thereafter, the fifth control unit 75 closes the release valve 92. Note that at this time, a second negative pressure value, which is the difference between the internal pressure of the partial suction path 921 (and the closed chamber 200) and the atmospheric pressure, is a value of -1 kPa or more and less than 0 kPa. In this case, the internal pressure of the partial suction path 921 and the closed chamber 200 becomes a pressure that is higher than the atmospheric pressure by more than 0 kPa and lower than 1 kPa. When the wafer 100 is thin, the second negative pressure value is set to -100 Pa or more and less than 0 Pa.

[0062] 8, the control unit 7 closes the suction on-off valve 475 of the fluid distribution mechanism 46 and opens the air supply on-off valve 485 and / or the water supply on-off valve 495. This causes air, water or a mixture of air and water to be 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.

[0063] Next, the sixth control unit 76 of the control unit 7 controls the moving mechanism 50 to move the suction pad 80, thereby transporting the wafer 100. That is, the sixth control unit 76 causes the moving mechanism 50 to raise the suction pad 80 holding the wafer 100, as shown by the arrow 302, to detach the wafer 100 from the holding surface 22. Thereafter, the sixth control unit 76 causes the moving mechanism 50 to transport the wafer 100, for example, to the spinner cleaning mechanism 156 shown in FIG. 1.

[0064] As described above, in the carry-out mechanism 172 according to this embodiment, the fifth control unit 75 of the control unit 7 opens the release valve 92 to communicate the closed chamber 200 with the partial suction path 921, which is at a negative pressure, to make the internal pressure of the closed chamber 200 negative, and the wafer 100 is sucked and held by the suction pad 80 (suction surface 801). That is, the partial suction path 921, which is a portion between the release valve 92 and the suction valve 93 in the suction path 91, is made negative pressure (first negative pressure value) like a suction tank, and then the negative pressure of the partial suction path 921 is used to make the closed chamber 200 a weak negative pressure (second negative pressure value), whereby the wafer 100 is sucked and held by the suction pad 80.

[0065] In this way, in the unloading mechanism 172, the internal pressure of the closed chamber 200 can be easily set to a weak negative pressure. This makes it possible to prevent the central portion of the wafer 100 from sagging when the wafer 100 is held by the suction pad 80, and also makes it possible to prevent a strong force from being applied to the wafer 100. Therefore, when the wafer 100 is transported by the unloading mechanism 172, it becomes possible to prevent damage to the wafer 100 caused by the central portion of the wafer 100 being pushed up by atmospheric pressure, etc.

[0066] In the unloading mechanism 172, the shock absorber 86 is connected to the closed chamber 200. As a result, for example, when the closed chamber 200 is formed by the second control unit 72, when the suction valve 93, the release valve 92, and the water supply valve 98 are closed by the third control unit 73, and when the release valve 92 is opened by the fifth control unit 75 and the closed chamber 200 becomes negative pressure, a part of the pressure fluctuation in the closed chamber 200 can be absorbed by the shock absorber 86. This makes it possible to reduce the pressure fluctuation applied to the suction surface 801 of the arm 81 and the back surface 102 of the wafer 100.

[0067] In this embodiment, the shock absorber 86 is provided on the upper surface of the suction pad 80 and communicates with the closed chamber 200. In this regard, the shock absorber 86 may be provided in a portion between the branching portion 96 in the suction path 91 and the suction port 802. Even in this configuration, the shock absorber 86 can reduce pressure fluctuations applied to the suction surface 801 and the back surface 102 of the wafer 100.

[0068] 1 may be configured to perform TAIKO grinding on the wafer 100. In this case, the grinding mechanism 70 grinds the back surface 102 of the wafer 100 to form a circular recess 110 and an annular protrusion 111 on the outer side of the circular recess 110 on the wafer 100, as shown in FIG.

[0069] 10, the seal portion 803 of the suction pad 80 comes into contact with the annular convex portion 111 of the wafer 100, forming a closed chamber 200 surrounded by the inner surface 803a of the seal portion 803, the suction surface 801, and the back surface 102 of the wafer 100. When transporting a TAIKO-ground wafer 100, the height (length in the Z-axis direction) of the seal portion 803 of the suction pad 80 may be relatively short.

[0070] In this case as well, the first to fourth control units set the difference between the internal pressure of the partial suction path 921 and the atmospheric pressure to a first negative pressure value that is equal to or less than the negative pressure value generated by the second suction source 94, and then the fifth control unit 75 opens the release valve 92. As a result, the closed chamber 200 is connected to the partial suction path 921 that is at a negative pressure, and the difference between the internal pressure of the closed chamber 200 and the atmospheric pressure becomes a second negative pressure value that is weaker than the first negative pressure value, and the wafer 100 can be sucked and held by the suction pad 80 (suction surface 801). Then, as shown in FIG. 11, the sixth control unit 76 controls the moving mechanism 50 to move the suction pad 80, thereby enabling the wafer 100 to be transported.

[0071] In this way, by holding and transporting the TAIKO-ground wafer 100 by the carry-out mechanism 172 under suction, it is possible to prevent the circular recess 110 of the wafer 100 from sagging, and also to prevent a strong force from being applied to the wafer 100 during transport. This makes it possible to effectively prevent the wafer 100 from being damaged during transport, for example, the occurrence of cracks at the boundary between the circular recess 110 and the annular protrusion 111 of the wafer 100 due to the circular recess 110 of the wafer 100 being pushed up by atmospheric pressure.

[0072] In the above-described embodiment, the grinding apparatus 1 including the grinding mechanism 70 is shown as an example of a processing apparatus equipped with the unloading mechanism 172. In this regard, the unloading mechanism 172 may be provided in other processing apparatuses such as a polishing apparatus that polishes the back surface 102 of the wafer 100. [Explanation of symbols]

[0073] 1: grinding device, 7: control unit, 10: first device base, 20: chuck table, 21: porous member, 22: holding surface, 23: frame, 25: rotation mechanism, 46: fluid distribution mechanism, 47: first suction source, 48: air supply source, 49: first water supply source, 50: moving mechanism, 51: column, 52: ball screw, 53: guide rail, 54: motor, 55: nut, 57: encoder, 60: grinding feed mechanism, 67: thickness measuring device, 70: grinding mechanism, 71: first control unit, 72: second control unit, 73: third control unit, 74: fourth control unit, 75: fifth control unit, 76: sixth control unit, 80: suction pad, 81: arm, 82: pivot column, 84: bolt, 85: check valve, 86: shock absorber, 90: base plate, 91: suction passage, 92: release valve, 93: suction valve, 94: second suction source, 95: suction shaft, 96: Branching portion, 97: Water supply passage, 98: Water supply valve, 99: Second water supply source, 100: wafer, 101: front surface, 102: back surface, 103: protective tape, 110: circular recess, 111: annular protrusion, 120: differential pressure gauge, 152: temporary placement mechanism, 155: robot, 156: spinner cleaning mechanism, 161: cassette, 163: cassette, 170: loading mechanism, 172: unloading mechanism, 200: closed room, 403: Suction groove, 470: Suction channel, 471: Suction piping, 473: Suction flow rate adjustment section, 475: suction opening / closing valve, 481: air piping, 483: air adjustment section, 485: air supply opening / closing valve, 491: water piping, 493: water adjustment section, 495: water supply opening / closing valve, 521: rotating shaft, 801: suction surface, 802: suction port, 803: sealing portion, 803a: inner surface, 804: first through hole, 805: first opening, 806: second through hole, 807: second opening, 811: annular member, 812: through hole, 821: rotating shaft, 841: shaft portion, 842: head portion, 843: spring, 921: Partial suction path

Claims

1. A transport device for transporting a wafer, the transport device comprising a suction pad that sucks and holds an upper surface side of a wafer by a suction surface, and a moving mechanism that moves the suction pad, The suction pad includes a ring-shaped seal portion disposed on an outer periphery of the suction surface, and a suction port formed on the suction surface and connected to a suction source; a suction passage connecting the suction port and the suction source; A branch portion disposed in the suction path; a water supply passage connecting the branch portion and a water supply source; a water supply valve disposed in the water supply passage; a suction valve disposed between the branched portion of the suction path and the suction source; a release valve disposed between the branched portion of the suction passage and the suction valve; A control unit, The control unit a first control unit that opens the suction valve, opens the release valve, and opens the water supply valve to fill the suction passage and the water supply passage with water; a second control unit that lowers the suction pad to bring the seal unit into contact with the upper surface of the wafer; a third control unit that closes the suction valve, the release valve, and the water supply valve in this order; a fourth control unit that controls a time for which the suction valve is opened, and sets a difference between an internal pressure between the suction valve and the release valve in the suction path and atmospheric pressure to a first negative pressure value that is equal to or lower than a negative pressure value generated in the suction source; a fifth control unit that controls a time for which the release valve is opened to set a difference between atmospheric pressure and an internal pressure of a closed chamber formed by an inner surface of the seal portion in contact with the upper surface of the wafer, the suction surface, and the upper surface of the wafer to a second negative pressure value that is weaker than the first negative pressure value, thereby suction-holding the wafer on the suction surface; and a sixth control unit that controls the moving mechanism to move the suction pad to transport the wafer. Conveying device.

2. The suction pad has an opening formed on the suction surface; a check valve that communicates the opening with the atmosphere, the check valve being configured to close when the opening side is under negative pressure and to open when the opening side is under positive pressure; The conveying device according to claim 1.

3. a shock absorber that can be connected to the closed chamber formed by the inner surface of the seal portion, the upper surface of the wafer, and the suction surface, and is filled with air; The conveying device according to claim 1.

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