Processing equipment

Abstract

To uniformly hold an in-plane thickness of a wafer after processing without grinding a holding surface when processing dust attached to the holding surface is removed.SOLUTION: A processing device 1 includes: a chuck table 10; a processing mechanism 20 for processing a wafer 100 held on the chuck table 10; a table cleaning mechanism 30 for cleaning the holding surface 11; and a control part 50, wherein the table cleaning mechanism 30 includes: a base 311; a Peltier element 312 arranged on a lower surface of the base 311; a power supply part 34 for supplying DC power to the Peltier element 312; a lifting mechanism 33 for moving the base 311; and a water tank (water bonding mechanism) 35 for bonding water to the Peltier element 312, and the control part 50 bonds the water to a lower surface of the Peltier element 312, supplies the DC power to the Peltier element 312 and forms ice 39 on the lower surface of the Peltier element 312, lowers the base 311, brings the ice 39 into contact with the holding surface 11 and cleans the holding surface 11.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a processing apparatus equipped with a table cleaning mechanism that cleans the holding surface of a chuck table that holds a wafer. [Background technology]

[0002] For example, a grinding machine for grinding wafers holds the wafer on the holding surface of a porous member of a chuck table, and grinds the upper surface of the wafer by rotating a grinding wheel and bringing it into contact with the upper surface of the wafer while supplying grinding water to the wafer. During the grinding of wafers by this grinding machine, the chuck table sucks the grinding water containing grinding debris from the outer edge of the wafer into the interior of the porous member.

[0003] Furthermore, the chuck table ejects a mixed fluid (two fluids) of water and air from the holding surface to separate the ground wafer from the holding surface. At this time, grinding debris sucked into the porous member of the chuck table may adhere to the holding surface (pierce or get caught). If the next wafer is held by suction on the holding surface of the chuck table with grinding debris attached, and then ground, the portions of the wafer where the grinding debris is present will be excessively ground, resulting in dimples (depressions) on the surface of the ground wafer, which will result in uneven wafer thickness and reduced quality.

[0004] Therefore, the holding surface of the chuck table is cleaned. As a cleaning means, for example, Patent Document 1 proposes a cleaning brush, and Patent Document 2 proposes a device in which two-fluid cleaning water composed of high-pressure air and liquid is sprayed at high pressure toward the holding surface of the chuck table.

[0005] Furthermore, Patent Document 3 proposes a foreign matter removal tool that includes a circular grinding stone portion made of a cleaning grinding stone (oil stone) adapted to contact the radial region between the center and outer periphery of the holding surface when removing foreign matter, and an annular brush adapted to contact the center and outer periphery of the holding surface when removing foreign matter, and a foreign matter removal method that uses this foreign matter removal tool. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-059881 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-200785 [Patent Document 3] Japanese Patent Application Publication No. 2015-030081 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the cleaning means using a cleaning brush proposed in Patent Document 1 has a problem in that scrapes (brush scraps) from the cleaning brush adhere to the holding surface. Also, the cleaning means proposed in Patent Document 2, which sprays two fluids at high pressure toward the holding surface of the chuck table, has a problem in that grinding scraps adhering to the holding surface of the chuck table cannot be blown away and completely removed by the spray of two fluids.

[0008] Therefore, the method of removing foreign matter such as grinding chips using a foreign matter removal tool proposed in Patent Document 3 is effective, but when the holding surface is scraped with a cleaning grindstone when removing the foreign matter, and the wafer held by suction on the scraped holding surface is then ground with a grinding grindstone, there is a problem in that the in-plane thickness of the wafer after grinding is not uniform.

[0009] Therefore, a processing device equipped with a chuck table that holds a wafer on the holding surface of a porous member has a problem of maintaining a uniform in-plane thickness of the wafer after processing without scraping the holding surface when removing processing debris adhering to the holding surface. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides a processing apparatus comprising a chuck table that holds a wafer on a holding surface of a porous member, a processing mechanism that processes the wafer held on the holding surface, a table cleaning mechanism that cleans the holding surface, and a control unit, wherein the table cleaning mechanism comprises a base, a Peltier element placed on the underside of the base, a power supply unit that supplies DC power to the Peltier element, an elevating mechanism that moves the base in a direction perpendicular to the holding surface, and a water landing mechanism that deposits water on the Peltier element, and the control unit deposits water on the underside of the Peltier element, supplies DC power so that the underside of the Peltier element is cooled to form ice on the underside of the Peltier element, and lowers the base to bring the ice into contact with the holding surface, thereby cleaning the holding surface. [Effects of the Invention]

[0011] According to the present invention, when the ice formed on the underside of the Peltier element is in contact with the holding surface of the chuck table, for example, the chuck table is rotated, so that the chips protruding from the holding surface are pierced by the ice and removed from the holding surface. Then, as the ice melts, the chips are removed and the holding surface is cleaned.

[0012] Furthermore, by rotating the chuck table, the underside of the ice melts and cleans the holding surface while remaining parallel to it, preventing the ice from scraping the holding surface and maintaining a uniform in-plane thickness of the processed wafer. In addition, as the underside of the ice melts, the corner where the underside and side of the ice intersect can be maintained, and this corner catches any machining debris adhering to the holding surface, ensuring that the machining debris is removed from the holding surface. Furthermore, the ice that comes into contact with the processing debris melts due to the processing debris, thereby incorporating the processing debris into the ice, thereby ensuring that the processing debris is removed from the holding surface.

[0013] Furthermore, if ice is brought into contact with the holding surface while cleaning water is supplied from a cleaning water supply unit that supplies cleaning water to the holding surface, the processing debris will be washed away by the cleaning water and will not remain on the holding surface. The wash water also melts the underside of the ice to maintain the shape of the corners and ensure that cutting debris is removed from the holding surface. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a cutaway perspective view of a grinding device which is one embodiment of a processing device according to the present invention. [Figure 2] 1 is a cutaway side view showing the configuration of a rotation drive mechanism and a table cleaning mechanism of a chuck table, which is one embodiment of a processing apparatus according to the present invention. FIG. [Figure 3] FIG. [Figure 4] FIG. 2 is a perspective view of the underside of the cleaning wheel. [Figure 5] FIG. 10 is a perspective view of the underside of a cleaning wheel according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] The embodiment of the present invention described below is an application of the present invention to a grinding apparatus that grinds wafers.

[0016] [Grinding equipment configuration] The grinding apparatus 1 shown in Figure 1 is an apparatus for grinding a disk-shaped wafer 100, which is a workpiece, and is equipped with a chuck table 10 that holds the wafer 100 on its upper circular holding surface 11 (see Figure 2), a grinding mechanism (processing mechanism) 20 that grinds the wafer 100 held by suction on the holding surface 11 of the chuck table 10, a table cleaning mechanism 30 that cleans the holding surface 11 of the chuck table 10, a cleaning water supply unit 40 (see Figure 2) that supplies cleaning water to the holding surface 11 of the chuck table 10, and a control unit 50.

[0017] 1, a plurality of devices (not shown) are formed on the surface facing downward, and these devices are protected by a protective tape (not shown) attached to the surface of the wafer 100. The front surface (the lower surface in FIG. 1) of the wafer 100 is suction-held on the holding surface 11 of the chuck table 10, and the back surface (the upper surface in FIG. 1) is ground by a grinding mechanism 20.

[0018] Next, the configurations of the chuck table 10, grinding mechanism 20, and table cleaning mechanism 30 that constitute the grinding device 1 will be described.

[0019] (Chuck table) The chuck table 10 is a disk-shaped member, and as shown in Fig. 2, 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. As shown in Fig. 2, the porous member 13 is connected to a suction source 45 such as a vacuum pump, the details of which will be described later.

[0020] Next, the configuration of the rotation drive mechanism of the chuck table 10 will be described below with reference to FIG.

[0021] 2, the chuck table 10 is attached to the upper part of a rotatable base member 14, and the base member 14 is rotatably supported via bearings 17 on an annular support member 16 fixed to a frame 15. A cylindrical rotary joint 19 is coaxially disposed below the base member 14 via a rotary shaft 18. A large-diameter driven pulley 2 is attached to the outer periphery of the small-diameter lower end of the base member 14.

[0022] Furthermore, a motor 4 is mounted vertically on the frame 15 via a stay 3, and a small-diameter drive pulley 6 is attached to the end of an output shaft (motor shaft) 5 extending vertically upward from the motor 4. An endless transmission belt 7 is wound between the drive pulley 6 and the driven pulley 2.

[0023] A continuous passage 8 is formed in the axial center of the base member 14, rotary shaft 18, and rotary joint 19, and the lower end of this passage 8 is connected to a passage 81 formed in the radial direction (horizontal direction) of the rotary joint 19. The passage 81 opens to the outer peripheral surface of the rotary joint 19.

[0024] In addition, a passage 82 communicating with the passage 8 and extending in the vertical direction, and a plurality of passages 83 (only two of which are shown in FIG. 2 ) extending horizontally and radially outward from the passage 82 are formed in the axial center of the chuck table 10. The one passage 82 and the plurality of passages 83 open to the lower surface of the porous member 13.

[0025] Furthermore, a pipe 9 is connected to a passage 81 formed in the rotary joint 19, and three pipes 91, 92, and 93 branch off from the pipe 9. The suction source 45 is connected to the pipe 91 via a variable orifice 43 and an electromagnetic on-off valve 44, and an air source 48 is connected to the pipe 92 via a variable orifice 46 and an electromagnetic on-off valve 47. Furthermore, a water source 52 is connected to the pipe 93 via a variable orifice 49 and an electromagnetic on-off valve 51. The electromagnetic on-off valves 44, 47, and 51 and the motor 4 are electrically connected to a control unit 50.

[0026] As shown in FIG. 1, the grinding apparatus 1 according to this embodiment includes a rectangular box-shaped base 70 that is long in the Y-axis direction (front-rear direction), and a rectangular block-shaped internal base 71 is housed inside the base 70. A horizontal movement mechanism 60 for moving the chuck table 10 along the Y-axis direction (front-rear direction) is provided on the internal base 71. The horizontal movement mechanism 60 includes a block-shaped slider 61 that is slidable in the Y-axis direction along a pair of left and right guide rails 62 that are arranged parallel to each other along the Y-axis direction (front-rear direction). Therefore, the chuck table 10 supported by the slider 61 and a rotation drive mechanism including the motor 4 shown in FIG. 2 are slidable along the Y-axis direction together with the slider 61.

[0027] A rotatable ball screw shaft 63 extending in the Y-axis direction (front-rear direction) is disposed between a pair of left and right guide rails 62 on the internal base 71, and one end of the ball screw shaft 63 in the Y-axis direction (the left end in FIG. 1) is connected to a motor 64, which serves as a drive source and can rotate forward and backward. The other end of the ball screw shaft 63 in the Y-axis direction (the right end in FIG. 1) is rotatably supported by a bearing 65 erected on the internal base 71. A nut member (not shown) protruding downward from the slider 61 is threadedly inserted into the ball screw shaft 63. Although not shown, the motor 64 is electrically connected to the control unit 50 (see FIG. 2).

[0028] Therefore, when the ball screw shaft 63 is rotated forward or backward by the motor 64, a nut member (not shown) threadedly inserted into the ball screw shaft 63 slides in the Y-axis direction (front-back direction) along the ball screw shaft 63 together with the slider 61, and the chuck table 10 also moves integrally along the Y-axis direction together with the slider 61. As a result, the wafer 100, which is the workpiece held by suction on the holding surface 11 (see FIG. 2) of the chuck table 10, also moves along the Y-axis direction.

[0029] (Grinding mechanism) The grinding mechanism 20 includes a spindle 21 having a rotation center axis in the Z-axis direction, a housing 22 that rotatably supports the spindle 21, a spindle motor 23 that rotationally drives the spindle 21, a mount 24 connected to the lower end of the spindle 21, and a grinding wheel 25 that is detachably attached to the lower surface of the mount 24. Here, the grinding wheel 25 includes a base 251 and a plurality of approximately rectangular parallelepiped segment grinding stones 252 arranged in an annular shape on the lower surface of the base 251. Note that each segment grinding stone 252 is a processing tool for grinding the wafer 100, and its lower surface forms a grinding surface that comes into contact with the wafer 100. Note that, although not shown, the spindle motor 23 is electrically connected to a control unit 50 (see FIG. 2).

[0030] As shown in Figure 1, a rectangular box-shaped column 72 is erected vertically on the +Y axis direction end (rear end) of the upper surface of the base 70, and a moving mechanism 80 is provided on the -Y axis direction end face (front face) of this column 72, which moves the grinding mechanism 20 up and down along the Z axis direction (up and down direction).

[0031] The moving mechanism 80 moves the grinding mechanism 20 up and down in a direction (Z-axis direction) perpendicular to the holding surface 11 (see FIG. 2) of the chuck table 10, and moves a rectangular plate-shaped lift plate 81 attached to the rear surface of the housing 22 up and down in the Z-axis direction along a pair of left and right guide rails 82 together with the housing 22 and the spindle 21, spindle motor 23, grinding wheel 25, etc. held by the housing 22. Here, the pair of left and right guide rails 82 are disposed perpendicular to the front surface of the column 72 and parallel to each other, and each of these guide rails 82 has a guide groove 821 (only one of which is shown in FIG. 1) formed along the up-down direction.

[0032] In addition, engagement protrusions (not shown) are provided above and below the locations of the lifting plate 81 corresponding to the guide grooves 821 of the pair of left and right guide rails 82, respectively, protruding rearward (in the +Y-axis direction), and these engagement protrusions slidably engage with the guide grooves 821 formed in each of the pair of left and right guide rails 82.

[0033] 1, a rotatable ball screw shaft 83 is installed vertically along the Z-axis direction (up and down direction) between the pair of left and right guide rails 82, and the upper end of the ball screw shaft 83 is connected to a motor 84, which serves as a drive source and can rotate forward and backward. The motor 84 is mounted in a vertical position via a rectangular plate-shaped bracket 85 attached to the upper surface of the column 72. Although not shown, the motor 84 is electrically connected to the control unit 50 (see FIG. 2).

[0034] In addition, the lower end of the ball screw shaft 83 is rotatably supported by the column 72, and a nut member (not shown) that protrudes horizontally toward the rear (+Y axis direction) from the back surface of the lifting plate 81 is threadedly inserted into this ball screw shaft 83.

[0035] (Table cleaning mechanism) 2 to 4, the table cleaning mechanism 30 includes a cleaning wheel 31 composed of a disk-shaped base 311 and a plurality of Peltier elements 312 arranged on the underside of the base 311, a motor 32 (see FIGS. 1 to 3) that rotates the cleaning wheel 31, an elevating mechanism 33 (see FIG. 1) that moves (raises and lowers) the cleaning wheel 31 together with the motor 32 in the Z-axis direction (up and down), a power supply unit 34 (see FIG. 2) that supplies DC power to each Peltier element 312, a cleaning water supply unit 40 (see FIG. 2) that supplies cleaning water to the chuck table 10, and a dish-shaped water tank 35 (see FIG. 1) that constitutes a water landing mechanism that deposits water on each Peltier element 312. As shown in FIG. 1, a water supply and drainage hole 351 is formed in the center of the bottom of the water tank 35, and this water supply and drainage hole 351 is connected to a water supply and drainage source (not shown).

[0036] In this embodiment, as shown in Fig. 4, the cleaning wheel 31 is configured by attaching 12 block-shaped Peltier elements 312 to the underside of the base 311 (the upper surface in Fig. 4) at equal angular pitches (30° pitches) in the circumferential direction, but the shape and number of Peltier elements 312 are arbitrary. For example, as shown in Fig. 5, the cleaning wheel 31 may be configured by attaching six cylindrical Peltier elements 312 to the underside of the base 311 (the upper surface in Fig. 5) at equal angular pitches (60° pitches) in the circumferential direction.

[0037] 2, a rotary connector 36 is interposed between the motor 32 and the lifting mechanism 33, and electrical wiring 37, 38 extending from the power supply unit 34 is electrically connected to each Peltier element 312 of the cleaning wheel 31. A base 311 of the cleaning wheel 31 is attached to the lower end of an output shaft (motor shaft) 321 extending vertically downward (in the −Z-axis direction) from the motor 32. The outer diameter of the cleaning wheel 31 (base 311) is set smaller than the outer diameter of the chuck table 10, and the inner diameter of the water tank 35 is set slightly larger than the outer diameter of the cleaning wheel 31 (base 311). As shown in FIGS. 1 and 2, the motor 32 and the lifting mechanism 33 are electrically connected to a control unit 50.

[0038] As shown in FIG. 2, the cleaning water supply unit 40 is composed of a cleaning water supply source 41 and a cleaning water spray nozzle 42 connected to the cleaning water supply source 41, and the cleaning water spray nozzle 42 is electrically connected to the control unit 50.

[0039] 1, the cleaning wheel 31 can be moved along the X-axis direction together with the motor 32 and the lifting mechanism 33. The slide mechanism 90 includes a slider 96 that can slide along the X-axis direction along two upper and lower guide rails 95 that are installed on gate-shaped pillars 94 that are erected vertically on the base 70. The lifting mechanism 33, together with the cleaning wheel 31 and the motor 32, is attached to the slider 96.

[0040] A ball screw shaft 97 extending along the X-axis direction is rotatably disposed at the vertical intermediate position of the upper and lower guide rails 95, and this ball screw shaft 97 is threadably inserted into the slider 96. One end (one end in the +X-axis direction) of the ball screw shaft 97 is connected to a motor 98 that can rotate forward and backward and is fixed to the support column 94, and the other end (one end in the -X-axis direction) of the ball screw shaft 97 is rotatably supported by the support column 94. The motor 98 is electrically connected to the control unit 50.

[0041] Therefore, when the motor 98 is driven to rotate the ball screw shaft 97 forward or backward, the slider 96 threadedly engaged with the ball screw shaft 97 slides along the X axis together with the lifting mechanism 33, the motor 32 and the cleaning wheel 31.

[0042] (Other components) As shown in FIG. 1, the grinding apparatus 1 of this embodiment includes, as other components, a cassette 101 for storing multiple wafers 100 before grinding, a cassette 102 for storing wafers 100 after grinding, a transfer mechanism 103 for transferring wafers into and out of the cassette 101, an alignment table 104 for positioning the wafers 100 transferred from the cassette 101, a first transfer mechanism 105 for transferring the wafers 100 positioned on the alignment table 104 to the chuck table 10, a cleaning mechanism 110 for cleaning the wafers 100 after grinding, and a second transfer mechanism 106 for removing the wafers 100 after grinding from the chuck table 10 and transferring them to the cleaning mechanism 110.

[0043] The cleaning mechanism 110 includes a spinner table 111 that holds and rotates the wafer 100 after grinding, and an injection nozzle 112 that injects cleaning water or high-pressure air.

[0044] [Function of grinding equipment] Next, grinding of the wafer 100 by the grinding apparatus 1 configured as above and cleaning of the chuck table 10 after grinding will be described.

[0045] When the wafer 100 is to be ground, the wafer 100 is placed with its surface facing down on the holding surface 11 of the chuck table 10. That is, the wafer 100 stored in the cassette 101 is taken out by the carry-in / out mechanism 103 and set on the alignment table 104. The wafer 100 is then aligned by the alignment table 104, and the aligned wafer 100 is placed on the chuck table 10 by the first transport mechanism 105.

[0046] 2, the control unit 50 opens (turns ON) the electromagnetic on-off valve 44 and closes (turns OFF) the other two electromagnetic on-off valves 47 and 51. Then, the air in the porous member 13 of the chuck table 10 passes through the passages 82, 83, 8, and 81 and the pipes 9 and 91 shown in FIG. 2 and is sucked into the suction source 45, generating a negative pressure 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.

[0047] 1 is driven to move the chuck table 10 in the +Y-axis direction (rearward) from the above state, and the wafer 100 suction-held on the chuck table 10 is positioned below the grinding wheel 25 of the grinding mechanism 20. That is, when the motor 64 is started and the ball screw shaft 63 rotates, the slider 61, to which a nut member (not shown) that is threadably inserted onto the ball screw shaft 63 is attached, slides in the +Y-axis direction along the pair of left and right guide rails 62 together with the chuck table 10 and the like, and the wafer 100 held on the holding surface 11 of the chuck table 10 is positioned below the grinding wheel 25 of the grinding mechanism 20.

[0048] 2 is driven to rotate the chuck table 10. That is, when the motor 4 is driven, the rotation of the output shaft 5 of the motor 4 is transmitted to the base member 14 and the chuck table 10 while being decelerated via the drive pulley 6, the transmission belt 7, and the driven pulley 2, and the wafer 100 held on the holding surface 11 of the chuck table 10 is rotated at a predetermined speed. At the same time, the control unit 50 starts the spindle motor 23 to rotate the grinding wheel 25 at a predetermined speed.

[0049] As described above, while the wafer 100 and the grinding wheel 25 are rotating, the moving mechanism 80 is driven to lower the grinding wheel 25 in the −Z-axis direction. That is, when the motor 84 is driven to rotate the ball screw shaft 83, the lifting plate 81, which is provided with a nut member (not shown) that threadably fits onto the ball screw shaft 83, is lowered in the −Z-axis direction together with the housing 22 and the grinding wheel 25. As a result, the lower surface (machining surface) of the segmented grindstone 252 of the grinding wheel 25 comes into contact with the upper surface (rear surface) of the wafer 100. When the grinding wheel 25 is further lowered a predetermined amount in the −Z-axis direction from the state in which the lower surface of the segmented grindstone 252 is in contact with the upper surface of the wafer 100, the upper surface of the wafer 100 is ground by a predetermined amount by the segmented grindstone 252.

[0050] When the grinding process on the wafer 100 is completed, the moving mechanism 80 raises the grinding mechanism 20. Then, the horizontal moving mechanism 60 is driven to move the slider 61 in the −Y-axis direction (forward), and the chuck table 10 and the wafer 100 are positioned below the cleaning wheel 31 of the table cleaning mechanism 30. From this state, the control unit 50 closes (turns OFF) the electromagnetic on-off valves 47 and 51 to terminate the vacuuming of the porous member 31, releases the wafer 100 from suction, and the second transfer mechanism 106 removes the wafer 100 from the chuck table 10 and places it on the spinner table 111 of the cleaning mechanism 110. The slider 61 may be a turntable on which multiple chuck tables are arranged. That is, the turntable may be rotated around the center of the turntable as the rotation axis, and the chuck tables arranged on the turntable may be positioned below the cleaning wheel 31 of the table cleaning mechanism 30.

[0051] In the cleaning mechanism 110, the spinner table 111 and the wafer 100 held thereon rotate at a predetermined speed, and cleaning water and high-pressure air are sprayed from the spray nozzles 112 toward the rotating wafer 100, so that the upper surface (surface to be ground) of the wafer 100 is cleaned with the cleaning water and high-pressure air, and foreign matter such as grinding debris adhering to the upper surface of the wafer 100 is removed. After cleaning in this manner, the wafer 100 is removed from the spinner table 111 by the carry-in / out mechanism 103 and stored in the cassette 102.

[0052] As described above, the chuck table 10 from which the wafer 100 has been removed is positioned below the cleaning wheel 31 of the table cleaning mechanism 30. While the second transport mechanism 106 is removing the wafer 100 from the chuck table 10, the slide mechanism 90 moves the cleaning wheel 31 from the position shown in FIG. 1 in the +X-axis direction to above the water tank 35. From this position, the lifting mechanism 33 lowers the cleaning wheel 31 in the -Z-axis direction, and the lower portions of the multiple Peltier elements 312 of the cleaning wheel 31 are immersed in water in the water tank 35. When the lifting mechanism 33 then raises the cleaning wheel 31 in the +Z-axis direction, water adheres to the underside of each Peltier element 312. At this time, the layer of water adhering to the underside of the Peltier elements 312 has thick and thin portions. However, by removing the thick layer of water at the upper edge of the peripheral wall of the water tank 35, the thickness of the layer of water adhering to the underside of each Peltier element 312 becomes uniform.

[0053] In the above state, the control unit 50 supplies DC power (DC current) from the power supply unit 34 shown in FIG. 2 to each Peltier element 312 of the cleaning wheel 31 via the electrical wiring 37 and 38. As a result, the water adhering to the underside of each Peltier element 312 is cooled to below the freezing point (0°C) and turns into ice 39. That is, as shown in FIGS. 2 to 5, ice 39 of a predetermined thickness is formed on the underside of each Peltier element 312. Alternatively, a metal plate having high thermal conductivity, such as aluminum, may be attached to the underside of each Peltier element 312, and a layer of ice 39 as shown in FIGS. 2 to 5 may be formed on the underside of this metal plate. In this embodiment, the lower portions of the Peltier elements 312 are immersed in water in the water tank 35 to adhere water to the underside of each Peltier element 312. However, water may also be sprayed onto the underside of the Peltier elements 312 using a spray bottle. Alternatively, water may be supplied to the holding surface 11 of the chuck table 10 by opening the electromagnetic on-off valve 51 disposed in a communication passage communicating with a water supply source, thereby forming a water layer, and the lower part of the Peltier element 312 may be placed in the water layer. However, ice 39 can be formed during grinding of the wafer 10 by a method of immersing the lower part of the Peltier element 312 in water in the water tank 35 or a method of spraying water onto the lower surface of the Peltier element 312 with a spray bottle.

[0054] 2 is removed from the chuck table 10 by the second transport mechanism 106, the control unit 50 opens (turns ON) the two electromagnetic on-off valves 47, 51 shown in FIG. 2, and high-pressure air and cleaning water (two fluids) are respectively sprayed upward from the underside of the porous member 13 through the pipes 92, 93, 9 and the passages 81, 8, 82, 83. Then, the grinding chips that are generated during the grinding process and that have been sucked into the porous member 13 attempt to be sprayed out from the holding surface 11 of the porous member 13, and at that time, they adhere to (pierce) the holding surface 11. In addition, grinding dust also adheres to the holding surface 11 of the porous member 13 during the grinding process.

[0055] As described above, when ice 39 is formed on the underside of each Peltier element 312 of the cleaning wheel 31, the control unit 50 sprays cleaning water from the cleaning water spray nozzle 42 of the cleaning water supply unit 40 toward the holding surface 11 of the chuck table 10, while driving the motor 32 to rotate the cleaning wheel 31 at a predetermined speed, and using the lifting mechanism 33 to lower the cleaning wheel 31 in the -Z axis direction so that the underside of the ice 39 formed on the underside of each Peltier element 312 abuts against the holding surface 11 of the chuck table 10.

[0056] Then, grinding chips protruding from the holding surface 11 of the chuck table 10 pierce the layer of ice 39 and are removed from the holding surface 11. Then, when the ice 39 subsequently melts, the grinding chips are removed and the holding surface 11 is cleaned.

[0057] Furthermore, by rotating the chuck table 10, the lower surface of the ice 39 melts and cleans the holding surface 11 while remaining parallel to the holding surface 11, so that the ice 39 does not scrape the holding surface 11 and the in-plane thickness of the processed wafer 100 is kept uniform.

[0058] Furthermore, in this embodiment, the holding surface 11 of the chuck table 10 is cleaned by bringing ice 39 into contact with the holding surface 11 while cleaning water is supplied from the cleaning water supply unit 40 that supplies cleaning water to the holding surface 11. As a result, the grinding chips are washed away by the cleaning water and do not remain on the holding surface 11.

[0059] As described above, the grinding device 1 according to the present invention has the advantage that the holding surface 11 is not scraped when removing foreign matter such as grinding chips adhering to the holding surface 11 of the chuck table 10, and the in-plane thickness of the processed wafer 100 can be maintained uniform.

[0060] Although the present invention has been described above as being applied to a wafer grinding machine, the present invention is also applicable to any processing machine other than grinding machines. For example, it may be used to clean the chuck table of a CMP polishing apparatus that polishes a wafer with a polishing pad while supplying slurry, or a dry polishing apparatus that polishes a wafer with a dry polishing pad.

[0061] 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 claims and the technical ideas described in the specification and drawings. [Explanation of symbols]

[0062] 1: Grinding device (processing device), 2: Driven pulley, 3: Stay, 4: Motor, 5: motor output shaft, 6: drive pulley, 7: transmission belt, 8, 81, 82, 83: Passageway, 9: Piping, 10: Chuck table, 11: holding surface of chuck table; 12: recess of chuck table; 13: porous member, 14: base member, 15: frame, 16: support member, 17: Bearing, 18: Rotating shaft, 19: Rotary joint, 20: Grinding mechanism (processing mechanism), 21: Spindle, 22: Housing, 23: Spindle motor, 24: Mount, 25: grinding wheel, 251: base, 252: segment grinding stone, 30: table cleaning mechanism, 31: cleaning wheel, 311: base, 312: Peltier element, 32: motor, 321: motor output shaft, 33: lifting mechanism, 34: power supply unit, 35: Water tank (landing mechanism), 351: Water supply and drainage hole, 36: Rotary connector, 37, 38: Electrical wiring, 39: Ice, 40: Cleaning water supply unit, 41: Cleaning water supply source, 42: cleaning water injection nozzle, 43: variable orifice, 44: electromagnetic on-off valve, 45: suction source, 46: Variable orifice, 47: Solenoid valve, 48: Air source, 49: Variable orifice, 50: control unit, 51: electromagnetic on-off valve, 52: water source, 60: horizontal movement mechanism, 61: slider, 62: guide rail, 63: ball screw shaft, 64: motor, 65: bearing, 70: base, 71: inner base, 72: column, 80: moving mechanism, 81: lifting plate, 82: guide rail, 821: guide groove, 83: ball screw shaft, 84: Motor, 85: Bracket, 90: Slide mechanism, 91: Support, 91, 92, 93: Piping, 94: Support, 95: Guide rail, 96: Slider, 97: Ball screw shaft, 98: Motor, 100: Wafer, 101, 102: cassette, 103: loading / unloading mechanism, 104: alignment table, 105: First transport mechanism, 106: Second transport mechanism, 110: Cleaning mechanism, 111: spinner table, 112: injection nozzle

Claims

1. A processing apparatus including a chuck table that holds a wafer on a holding surface of a porous member, a processing mechanism that processes the wafer held on the holding surface, a table cleaning mechanism that cleans the holding surface, and a control unit, the table cleaning mechanism includes a base, a Peltier element disposed on the underside of the base, a power supply unit that supplies DC power to the Peltier element, a lifting mechanism that moves the base in a direction perpendicular to the holding surface, and a water landing mechanism that deposits water on the Peltier element; The control unit controls the processing device to adhere water to the underside of the Peltier element, supply DC power to cool the underside of the Peltier element to form ice on the underside of the Peltier element, and lower the base to bring the ice into contact with the holding surface and clean the holding surface.

2. a cleaning water supply unit that supplies cleaning water to the holding surface; 2. The processing apparatus according to claim 1, wherein the control unit brings ice into contact with the holding surface while supplying cleaning water from the cleaning water supply unit, thereby cleaning the holding surface.

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