Washing device

Abstract

To shorten a time required for replacing a dirty sponge.SOLUTION: A device 4 for washing a wafer lower surface is provided, configured in such a manner that a part of an outside surface of a roll sponge 43 not freely rotated is brought into contact with a lower surface of a wafer held by a holding mechanism 42, and the wafer and the sponge 43 are relatively moved in a direction parallel to the lower surface of the wafer, the device for washing the wafer lower surface comprises: a shaft 40 extending in a direction partial to the lower surface of the wafer held by the holding mechanism 42; a sponge 43 that is inserted into the shaft 40; a shaft support mechanism 5; a mechanism 46 supplying washing water to the sponge 43; and a mechanism 48 that relatively moves the sponge 43 and the holding mechanism 42 to a direction parallel to the lower surface of the held wafer. The support mechanism 5 comprises: a first support portion 51 supporting one end of the shaft; and a second support portion 52 supporting the other end of the shaft, and further comprises a spring 53 that is arranged between the first support portion 51 and the second support portion 52, and energizes the shaft 40 toward the first support portion 51 from the second support portion 52, wherein the shaft 40 into which the sponge 43 is inserted by the spring 53 can be easily detached to and attached from the device for washing the wafer lower surface.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a cleaning device for cleaning the lower surface of a wafer.

Background Art

[0002] For example, the grinding device disclosed in Patent Document 1 includes a cleaning device that cleans by bringing a part of a roll-shaped sponge into contact with the lower surface of a wafer. Dirt adheres to the part of the sponge that contacts the lower surface of the wafer. And the dirt adhering to the sponge may reattach to the wafer. Therefore, as disclosed in Patent Document 2 for example, the sponge is rotated about a rotation axis having the extending direction of the sponge as the axial direction during cleaning of the wafer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when the sponge rotates, the dirt that has flowed down to the lower side surface of the sponge may move to the upper side surface and reattach dirt to the wafer. And in this cleaning device, for example, the wafer before grinding is being cleaned. If dirt (adhesions) adheres to the lower surface of the cleaned wafer, the wafer will be ground with the adhesion intervening between the lower surface of the wafer and the holding surface that sucks and holds the wafer on the chuck table. Therefore, there is a problem that the part where the adhesion intervenes becomes thinner and the thickness of the ground wafer is not uniform.

[0005] In addition, this cleaning device may also clean the wafer after grinding. Also in this case, if dirt (grinding debris) adheres to the lower surface of the cleaned wafer, the grinding debris will adhere to the spinner table that becomes the transfer destination of the wafer and cleans the upper surface of the wafer. Therefore, there is a problem that the grinding debris adhering to the spinner table may damage (form scratches or cause cracks) the wafer subsequently held by suction on the spinner table.

[0006] Therefore, for example, in a cleaning device disposed in a grinding device and cleaning the lower surface of a wafer with a roll-shaped sponge, there is a problem of shortening the replacement time of the dirty sponge so as not to cause a situation where the grinding process is delayed for a long time due to wafer cleaning. In addition, there is a problem of cleaning the wafer by wiping off the dirt on the wafer without rotating the sponge during cleaning so that no deposits such as dirt adhere to the cleaned wafer.

Means for Solving the Problems

[0007] The present invention for solving the above problems is a cleaning device that brings a part of the outer surface of a roll-shaped sponge that does not rotate freely into contact with the lower surface of a wafer, and relatively moves the wafer and the sponge in a direction intersecting the extending direction of the sponge to clean the lower surface of the wafer, comprising: a holding mechanism for holding the wafer; a support shaft extending in a direction parallel to the lower surface of the wafer held by the holding mechanism; the sponge having an insertion hole for inserting the support shaft; a support mechanism for supporting the support shaft; a cleaning water supply mechanism for supplying cleaning water to the sponge; Move the sponge and the holding mechanism relative to each other in a direction intersecting the extending direction of the sponge a moving mechanism, and the support mechanism includes a first support portion for supporting one end side of the support shaft and a second support portion for supporting the other end side of the support shaft, and is disposed between the first support portion and the second support portion, and includes a biasing member that biases the support shaft from one of the first support portion and the second support portion toward the other support portion, and the cleaning device is such that the support shaft into which the sponge is inserted can be easily detached and attached by the biasing member. For example, it is preferable that the support mechanism includes a rotation angle determining unit that enables the support shaft to rotate intermittently at a preset rotation angle, and the support shaft is rotated by the rotation angle determining unit so that the portion of the sponge in contact with the wafer can be switched. Furthermore, it is preferable that the first support portion or the second support portion is provided with a ratchet mechanism including the rotation angle determining unit, and in the moving direction of the sponge with respect to the holding mechanism holding the wafer when cleaning the lower surface of the wafer, the support shaft into which the sponge is inserted is not rotated, and in the direction opposite to the moving direction, the support shaft can be rotated to switch the portion of the sponge in contact with the wafer. In addition, it is preferable to include a rotating shaft extending in a direction perpendicular to the lower surface of the wafer held by the holding mechanism, and a shaft rotating mechanism for rotating the rotating shaft, and the support shaft is arranged so as to extend horizontally in a plurality of directions perpendicular to the rotating shaft and outward from the rotating shaft.

Advantages of the Invention

[0008] A cleaning device according to the present invention that cleans the lower surface of a wafer by bringing a part of the outer surface of a roll-shaped sponge that does not rotate freely into contact with the lower surface of the wafer and relatively moving the wafer and the sponge in a direction intersecting the extending direction of the sponge includes a support shaft extending in a direction parallel to the lower surface of the wafer held by a holding mechanism, a sponge having an insertion hole into which the support shaft is inserted, and a support mechanism that supports the support shaft. The support mechanism includes a first support portion that supports one end side of the support shaft and a second support portion that supports the other end side of the support shaft. By providing a biasing member that biases the support shaft from one of the first support portion and the second support portion toward the other support portion and is disposed between the first support portion and the second support portion, the biasing member (for example, a compression spring) facilitates the detachment and attachment of the sponge between the first support portion and the second support portion of the support shaft into which the sponge is inserted, and the sponge can be easily exchanged and the cleaning surface can be switched in a short time. Therefore, it is possible to prevent a situation in which, for example, the grinding process in a grinding device equipped with a cleaning device is delayed for a long time due to the wafer cleaning being a bottleneck. For example, the support mechanism includes a rotation angle determining portion that enables the support shaft to rotate intermittently at a preset rotation angle, and the support shaft can be rotated by the rotation angle determining portion to switch the portion of the sponge that contacts the wafer. That is, when cleaning the wafer, the sponge is not rotated about the support shaft, and a part of the roll-shaped sponge is brought into contact for cleaning. Therefore, unlike the conventional method, a situation in which dirt flowing down the lower side surface of the sponge due to the rotation of the sponge about the support shaft moves back to the upper side surface and reattaches to the wafer does not occur. And, for example, when an operator determines that a part of the sponge that was in contact with the wafer has become dirty to an unacceptable level, the outer surface of the sponge can be switched from the dirty part to the non-dirty part, and it is possible to prevent dirt from adhering to the wafer from the sponge. Furthermore, a ratchet mechanism including a rotation angle determination portion is provided in the first support portion or the second support portion. When the sponge moves relative to the holding mechanism holding the wafer during cleaning of the lower surface of the wafer, the ratchet mechanism does not rotate the support shaft into which the sponge is inserted in the moving direction of the sponge, and in the direction opposite to the moving direction, the support shaft can be rotated to switch the portion where the sponge contacts the wafer. Thus, the apparatus can automatically switch the sponge at an appropriate timing without manual operation by the operator.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] The grinding apparatus 1 shown in FIG. 1 is an apparatus for thinning a wafer 90 held on any one of the chuck tables 18 to a desired thickness by a rough grinding unit 30 and a finish grinding unit 31. The grinding apparatus 1 is configured, for example, by connecting a second apparatus base 11 to the rear (+Y direction side) of a first apparatus base 10. On the first apparatus base 10, there is a loading / unloading area where the wafer 90 is loaded and unloaded. On the second apparatus base 11, there is a grinding area where the wafer 90 held by the chuck table 18 is ground by the rough grinding unit 30 and the finish grinding unit 31. Note that the grinding device 1 may be a manual type grinding device that positions the wafer 90 suction-held by the chuck table 18 that can linearly move in the Y-axis direction below the single-axis grinding unit.

[0011] The wafer 90 shown in FIG. 1 is, for example, a circular semiconductor wafer made of a silicon base material or the like. In FIG. 1, the surface 900 (lower surface 900) of the wafer 90 facing downward has a plurality of devices formed thereon, and a protective tape 91 is attached and protected. The back surface 903 (upper surface 903) facing upward of the wafer 90 is the surface to be machined by grinding. Note that the wafer 90 is not limited to a silicon wafer and may be made of gallium arsenide, sapphire, ceramics, resin, gallium nitride, silicon carbide, or the like. The wafer 90 may not have devices formed thereon. Also, instead of the protective tape 91, a resin sheet called a reflow flat or a substrate such as a metal plate may be adhered to the lower surface 900 of the wafer 90. Alternatively, none of the above various protective members or handling substrates may be adhered to the lower surface 900 of the wafer 90, and the lower surface 900 may be the exposed surface.

[0012] On the front side (-Y direction side) of the first device base 10, a first cassette mounting portion 150 and a second cassette mounting portion 151 are provided. A first cassette 154 that houses the wafer 90 before processing is placed on the first cassette mounting portion 150, and a second cassette 155 that houses the wafer 90 after processing is placed on the second cassette mounting portion 151.

[0013] Behind the opening of the first cassette 154, a robot 157 is arranged to carry out the wafer 90 before processing from the first cassette 154 and carry the wafer 90 after processing into the second cassette 155. A temporary placement area 152 is provided at a position adjacent to the robot 157, and an alignment unit 153 is arranged in the temporary placement area 152. The alignment unit 153 aligns (centers) the wafer 90 carried out from the first cassette 154 and placed in the temporary placement area 152 to a predetermined position with a centering pin that reduces the diameter.

[0014] At a position adjacent to the alignment unit 153, a first holding mechanism 41 that rotates while holding the wafer 90 is arranged. The first holding mechanism 41 holds the wafer 90 aligned in the alignment unit 153 and conveys it to any one of the chuck tables 18 arranged in the grinding area. Adjacent to the first holding mechanism 41, a second holding mechanism 42 that rotates while holding the wafer 90 after processing is provided.

[0015] Since the first holding mechanism 41 and the second holding mechanism 42 have the same configuration, only the second holding mechanism 42 will be described below, and the same reference numerals will be given to the first holding mechanism 41 and the description will be omitted.

[0016] The second holding mechanism 42 includes a holding pad 420 in the shape of a circular plate in plan view, a vertical movement unit 421 that moves the holding pad 420 up and down in the Z-axis direction, and a horizontal movement unit 423 that moves the holding pad 420 in the horizontal direction (X-axis Y-axis plane direction).

[0017] The horizontal movement unit 423 is, for example, a rotary actuator or the like, and includes an arm portion 424 that extends parallel to the horizontal direction and has the holding pad 420 mounted on the lower surface side of its tip, a turning shaft portion 425 whose axial direction is the Z-axis direction and that turns and moves the arm portion 424 in the horizontal direction, and a turning motor (not shown) connected to the turning shaft portion 425. Note that the horizontal movement unit 423 may be a linear movement unit that linearly moves the holding pad 420 in the X-axis direction or the Y-axis direction.

[0018] The holding pads 420 shown in FIGS. 1 and 2 include a porous plate 427 having a flat lower surface as a holding surface 426, and a frame body 428 that supports the porous plate 427. An air flow path 429 communicates with the holding surface 426 through the frame body 428 and an arm portion 424 connected to the frame body 428. The upstream of the air flow path 429 branches into two, and an air supply source 4292 composed of a compressor or the like communicates with one of the branched flow paths via an air supply valve 4291. A suction source 4298 such as an ejector or a vacuum generator communicates with the other branched flow path via an air suction valve 4299. The suction source 4298 generates a suction force when the holding pad 420 sucks and holds the wafer 90, and the air supply source 4292 supplies air for removing the vacuum adsorption force when the wafer 90 held by the holding pad 420 is released.

[0019] For example, the vertical movement unit 421 shown in FIG. 1 is an electric cylinder including a rod, a motor, etc. and connected to the swivel shaft portion 425. The vertical movement unit 421 can move the holding pad 420 to a predetermined height position in the vertical direction (Z-axis direction) by raising and lowering the swivel shaft portion 425. Note that the vertical movement unit 421 is not limited to an electric cylinder, and may be an air cylinder or the like.

[0020] Within the movable ranges of the first holding mechanism 41 and the second holding mechanism 42 shown in FIG. 1, a single-wafer spinner cleaning mechanism 156 for cleaning the processed wafer 90 conveyed by the second holding mechanism 42 is arranged. The spinner cleaning mechanism 156 rotates the spinner table 1561 while sucking and holding the lower surface 900 side of the wafer 90 with the spinner table 1561 that is circular in plan view, and sprays cleaning water from a cleaning nozzle (not shown) that swivels above the wafer 90 onto the upper surface 903, which is the surface to be ground, of the wafer 90 to clean the upper surface 903. The wafer 90 cleaned by the spinner cleaning mechanism 156 is carried into the second cassette 155 by the robot 157.

[0021] On the rear side (+Y direction side) of the second device base 11, a first column 12 is erected, and a rough grinding feed unit 39 is disposed on the front surface of the first column 12. The rough grinding feed unit 39 includes a ball screw 390 having an axis in the vertical direction (Z-axis direction), a pair of guide rails 391 disposed in parallel with the ball screw 390, a motor 392 connected to the ball screw 390 to rotate the ball screw 390, a lifting plate 393 whose internal nut is screwed onto the ball screw 390 and whose side portion is in sliding contact with the guide rail 391, and a holder 394 connected to the lifting plate 393 to hold the rough grinding unit 30. When the motor 392 rotates the ball screw 390, accordingly, the lifting plate 393 is guided by the guide rail 391 and reciprocates in the Z-axis direction, and the rough grinding unit 30 supported by the holder 394 also reciprocates in the Z-axis direction.

[0022] The rough grinding unit 30 includes a spindle 300 whose axial direction is the vertical direction (Z-axis direction), a housing 301 that rotatably supports the spindle 300, a motor 302 that rotationally drives the spindle 300, a circular mount 303 connected to the lower end of the spindle 300, and a grinding wheel 304 detachably connected to the lower surface of the mount 303. And the grinding wheel 304 includes a wheel base 305 and a plurality of rough grinding grinding wheels 306 having a substantially rectangular parallelepiped shape annularly disposed on the bottom surface of the wheel base 305. The rough grinding grinding wheel 306 is, for example, a grinding wheel in which the abrasive grains contained in the grinding wheel are relatively large. For example, inside the spindle 300, a grinding water flow path extending in the Z-axis direction is formed, and a grinding water supply unit (not shown) communicates with this grinding water flow path. The grinding water supplied from the grinding water supply unit to the spindle 300 jets downward from the opening at the lower end of the grinding water flow path through the mount 303 and the wheel base 305 toward the rough grinding grinding wheel 306 and reaches the contact portion between the rough grinding grinding wheel 306 and the wafer 90.

[0023] Further, behind the second equipment base 11, a second column 13 stands upright in parallel with the first column 12 in the X-axis direction, and a finish grinding feed unit 36 is arranged on the front surface of the second column 13. The finish grinding feed unit 36 is configured in the same manner as the rough grinding feed unit 39 and can feed the finish grinding unit 31 in the Z-axis direction for grinding. The finish grinding unit 31 is provided with a finish grinding wheel 315 in which the abrasive grains contained in the grinding wheel are relatively small, and the other configurations are the same as those of the rough grinding unit 30.

[0024] At a position near the rough grinding unit 30 or the finish grinding unit 31 that has descended to the height position when grinding the wafer 90, for example, a thickness measurement gauge 38 for measuring the thickness of the wafer 90 in a contact manner during grinding is respectively arranged.

[0025] As shown in FIG. 1, a turntable 17 is arranged on the second equipment base 11, and, for example, three chuck tables 18 are arranged on the upper surface of the turntable 17 at equal intervals in the circumferential direction. At the center of the turntable 17, a rotating shaft (not shown) for rotating the turntable 17 is arranged, and the turntable 17 can rotate about a rotating shaft whose axial direction is the Z-axis direction. By the rotation of the turntable 17, the three chuck tables 18 can be revolved and positioned sequentially from the vicinity of the temporary placement area 152 below the rough grinding unit 30 and below the finish grinding unit 31.

[0026] The chuck table 18 has, for example, a circular outer shape, and the upper surface is a holding surface 180 made of a porous member or the like, and a suction source (not shown) communicates with the holding surface 180. Then, the lower surface 900 side of the wafer 90 can be sucked and held via the protective tape 91 by the holding surface 180 to which the suction force is transmitted from the suction source.

[0027] The grinding device 1 is provided with a cleaning device 4 according to the present invention. The cleaning device 4 shown in detail in FIG. 3 brings a part of the outer surface of a roll-shaped sponge 43 that does not rotate freely into contact with the lower surface 900 of the wafer 90 (in this embodiment, the protective tape 91), and in a direction intersecting in the horizontal plane (in the X-axis Y-axis plane) in the extending direction of the sponge 43. For example, the wafer 90 and the sponge 43 are relatively moved to clean the protective tape 91 on the lower surface 900 of the wafer 90. Note that the cleaning device 4 may clean the lower surface 900 of the wafer 90 to which the protective tape 91 is not attached.

[0028] The cleaning device 4 holds the wafer 90 It is a holding mechanism The first holding mechanism 41 Or The second holding mechanism 42 (see FIGS. 1 and 2) Clean the lower surface of the wafer 90 held thereon. The cleaning device 4 is, for example, The 2 Holding mechanism 4 2 And a support shaft 40 shown in FIG. 3 that extends in a direction (horizontal direction) parallel to the lower surface 900 of the wafer 90 held by the holding mechanism 4, a sponge 43 having an insertion hole into which the support shaft 40 is inserted, a support mechanism 5 that supports the support shaft 40, a cleaning water supply mechanism 46 that supplies cleaning water to the sponge 43, and the sponge 43 in a direction intersecting the extending direction of the sponge 43 in the horizontal plane. 、 For example, a moving mechanism 48 that relatively moves the second holding mechanism 42 and the like. In addition, the wafer 90 held by the first holding mechanism 41 similar to the second holding mechanism 42 may be cleaned by the cleaning device 4.

[0029] The sponge 43 shown by the broken line in FIG. 3 is a roll sponge formed by shaping a sponge having a predetermined thickness into a cylindrical shape. For example, it extends with a length greater than or equal to the radius of the wafer 90, and an insertion hole is formed from one end to the other end at its center. The sponge 43 is, for example, an open-cell sponge having a structure in which air bubbles communicate with each other, and is a sponge made by foam molding polyurethane (for example, Sofras sponge manufactured by Ion Co., Ltd.), a PVA sponge (for example, Bell Eater sponge manufactured by Ion Co., Ltd.), or a sponge formed by kneading a foaming agent into rubber. etc. are used. Note that the sponge 43 may be a single-cell sponge. The outer surface of the sponge 43 becomes a cleaning surface that contacts and cleans the protective tape 91 on the lower surface 900 of the wafer 90 in this embodiment.

[0030] As shown in FIG. 3, for example, three sponges 43 are arranged in this embodiment on a support plate 449 that supports the sponge 43 via a support shaft 40. Note that the number of sponges 43 arranged may be one, two, or four or more. The support plate 449 includes a circular flat base 4490 and three extending portions 4491 that are integrally formed with the base 4490 and extend from the outer peripheral side of the base 4490 in at least three directions, for example, horizontally, at equal angles (for example, 120 degrees).

[0031] A rotary shaft 480 that constitutes a moving mechanism 48 is connected to the center of the lower surface of the base 4490 of the support plate 449. The rotary shaft 480 has an axial direction that is the Z-axis direction, which is perpendicular to the lower surface 900 of the wafer 90 sucked and held on the flat holding surface 426 of the second holding mechanism 42 shown in FIG. 2, for example. A shaft rotation mechanism 481 is connected to the lower end side of the rotary shaft 480. That is, the moving mechanism 48 in this embodiment rotates the support plate 449 to circulate the three sponges 43 arranged on the support plate 449 around the rotary shaft 480. The shaft rotation mechanism 481 preferably includes, for example, a pulley mechanism or the like in which a rotation motor serving as a rotation drive source is arranged horizontally offset from the rotary shaft 480 in order to reduce the weight in the vertical direction (Z-axis direction) applied to the rotary shaft 480. Note that the rotary shaft 480 may not be provided. That is, the support plate 449 may not be rotated.

[0032] The axis of the rotating shaft 480 coincides with the center of the base 4490 of the support plate 449. On the other hand, for example, the support shafts 40 that support the three sponges 43 respectively are arranged offset in the horizontal plane so as not to pass through the center of the base 4490 of the support plate 449 (the axis of the rotating shaft 480). By arranging them such that the rotation trajectories of the central sides of the three sponges 43 that support and orbit in the horizontal plane (hereinafter, taken as one end side connected to and supported by the first support portion 51 described later) overlap, the three sponges 43 that orbit can also contact the central region of the protective tape 91 on the lower surface 900 of the wafer 90. That is, in the present embodiment, the support shafts 40 are arranged such that a plurality (three) extend horizontally orthogonally in the horizontal plane (within the X-axis Y-axis plane) from the rotating shaft 480 and outward. Note that a configuration may also be adopted in which a plurality of support shafts 40 extend radially and horizontally around the axis of the rotating shaft 480. Also, the rotating shaft 480 and the support plate 449 may be vertically movable in the Z-axis direction by a vertical movement mechanism (not shown). Note that the axis of the rotating shaft 480 coincides with the center of the support plate 449.

[0033] As shown in FIG. 3, inside the rotating shaft 480, an in-axis water flow path 4801 that passes through its center and serves as a path for cleaning water is formed to penetrate in the Z-axis direction. The upper end side of the in-axis water flow path 4801 communicates with a cleaning water distribution path (not shown) formed inside the first support portion 51 described later. The lower end side of the in-axis water flow path 4801 communicates with a cleaning water supply source 469 that constitutes the cleaning water supply mechanism 46 and includes a pump or the like via a seal unit, a joint, a resin tube, or the like that prevents leakage of the cleaning water.

[0034] The support mechanism 5 shown in FIG. 3 includes a first support portion 51 that supports one end side of the rotating shaft 480 of the support shaft 40 closer to the axis, and a second support portion 52 that supports the other end side of the support shaft 40 farther from the axis of the rotating shaft 480. A compression spring 53 is provided as a biasing member that is disposed between the first support portion 51 and the second support portion 52 and biases the support shaft 40 from one support portion (in this embodiment, the second support portion 52) toward the other support portion (in this embodiment, the first support portion 51). Note that instead of the compression spring 53, a rubber cylinder as a biasing member may be used.

[0035] The first support portion 51 is, for example, erected at the center of the upper surface of the base portion 4490 of the support plate 449, and has a shape in which three plate-like support walls 510 extend from the center of the upper surface of the base portion 4490 toward the vertices of a virtual triangle in a plan view. As shown enlarged in FIG. 3, insertion holes 511 having an annular step into which one end side of the support shaft 40 is inserted are formed on the side surfaces of the three support walls 510. Further, for example, one substantially columnar positioning projection 572 is formed so as to project from the side surface of the support wall 510 around the outer periphery of the insertion hole 511. Note that two or more positioning projections 572 may be formed. In FIG. 3, in the overall perspective view of the cleaning device 4, a state in which the support shaft 40 is connected to the support wall 510 is shown, and in a partially enlarged view, a state in which the support shaft 40 is separated from the support wall 510 is shown.

[0036] The support shaft 40 is longer in overall length than the sponge 43, and one end side supported by the first support portion 51 is a columnar reduced-diameter portion 400 whose diameter is reduced by one step compared to the shaft body 409 that contacts the sponge 43 as shown in the enlarged view. For example, the sponge 43 is set to be slightly longer than the shaft body 409 of the support shaft 40. An O-ring 401 made of rubber or the like is preliminarily inserted into the reduced-diameter portion 400 of the support shaft 40. In a state where the sponge 43 is inserted into the support shaft 40, the reduced-diameter portion 400 and the O-ring 401 protrude outward from one end side of the sponge 43, and the reduced-diameter portion 400 is inserted into the insertion hole 511 together with the O-ring 401. Since the insertion hole 511 has an annular stepped surface, the O-ring 401 having a larger diameter than the reduced-diameter portion 400 abuts against the annular stepped surface on the outer side of the insertion hole 511 by one step and is fitted into the insertion hole 511, so that the situation where the O-ring 401 comes off the support shaft 40 does not occur. The O-ring 401 prevents water leakage when the cleaning water sent from the cleaning water supply source 469 and passing through the water flow path 4801 in the shaft and the first support portion 51 moves to the support shaft 40 side.

[0037] The support shaft 40 includes a lock plate 571 integrally formed on the reduced-diameter portion 400 to prevent the support shaft 40 from rotating freely during wafer cleaning together with the positioning projection 572, and a shaft body 409 integrally connected to the back surface of the lock plate 571. The lock plate 571 is formed to have a diameter slightly larger than that of the shaft body 409, and the front surface on the reduced-diameter portion 400 side abuts against the support wall 510.

[0038] On the outer periphery of the lock plate 571, a semi-circular notch groove 5711 is formed. The width of the notch groove 5711 is set to be slightly larger than the diameter of the cylindrical positioning projection 572, so that the notch groove 5711 can move and fit in the extending direction of the support shaft 40 toward the positioning projection 572. In the present embodiment, as shown when viewed from the extending direction side of the support shaft 40 in FIG. 4, on the outer periphery of the lock plate 571, eight notch grooves 5711 are formed at intervals of, for example, 45 degrees in the circumferential direction of the lock plate 571. Note that the number and intervals of the notch grooves 5711 are not limited to this example.

[0039] The support mechanism 5 shown in FIG. 3 in the present embodiment includes a rotation angle determination unit 57 that enables the support shaft 40 to perform intermittent rotation (i.e., step rotation by a predetermined angle) at a preset rotation angle (in the present embodiment, 45 degrees). And the rotation angle determination unit 57 in the present embodiment is composed of a lock plate 571 formed on the support shaft 40 and a positioning projection 572. By the rotation angle determination unit 57, the support shaft 40 is intermittently rotated at a timing other than during wafer cleaning by, for example, an operator, so that it is possible to switch the portion in contact with the protective tape 91 of the wafer 90 of the sponge 43 arranged so as not to freely rotate during wafer cleaning at a desired timing.

[0040] The hollow pipe-shaped support shaft 40 shown in FIGS. 3 and 4 has a flow path 408 (shown by a dashed-dotted line in the enlarged view in FIG. 3) formed inside and extending in parallel so as to penetrate, for example, in the extending direction of the support shaft 40. The flow path 408 communicates with a plurality of water supply holes 407 opened on the outer surface of the support shaft 40. The water supply holes 407 are opened on the outer surface of the support shaft 40 at equal intervals in the circumferential direction and the extending direction. Note that the flow path 408 does not penetrate the support shaft 40 from one end side to the other end side, and may penetrate the support shaft 40 only at one end side connected to the first support portion 51 at least. In addition, when the flow path 408 is formed to penetrate the support shaft 40, a compression spring 53 with a strength that is not compressed by the water pressure of the cleaning water supplied to the flow path 408 is set.

[0041] Inside the first support portion 51 shown in FIG. 3 that also functions as a manifold, a cleaning water distribution path (not shown) that constitutes a cleaning water supply mechanism 46 and divides the cleaning water supplied to the sponge 43 into three is formed. One end of the cleaning water distribution path (not shown) communicates with an insertion hole 511 connected to the flow path 408 of the support shaft 40, and the other end communicates with the upper end of the in-shaft water flow path 4801 of the rotating shaft 480 connected to the lower surface side of the base portion 4490. Then, the cleaning water sent from the cleaning water supply source 469 shown in FIG. 3 and finally supplied to the sponge 43 from the plurality of water supply holes 407 of the support shaft 40 oozes out from the inside (the inner surface of the insertion hole) of the sponge 43 to the outer surface of the sponge 43, washes away the dirt adhering to the outer surface of the sponge 43, and reaches the contact portion between the protective tape 91 of the wafer 90 and the outer surface of the sponge 43.

[0042] Note that the cleaning water supply mechanism 46 is not limited to a configuration in which the cleaning water is supplied to the sponge 43 through the in-shaft water flow path 4801 of the rotating shaft 480, the inside of the first support portion 51, the insertion hole 511 of the first support portion 51, the flow path 408 of the support shaft 40 communicating with the insertion hole 511, and the water supply hole 407 of the support shaft 40, and may be provided with a cleaning water nozzle that directly injects the cleaning water toward the outer surface of the sponge 43.

[0043] On substantially the entire outer surface of the shaft body 409 of the support shaft 40 shown in FIGS. 3 and 5, an anti-slip groove 4098 that circumferentially winds around the outer surface in a spiral shape is formed. The spiral anti-slip groove 4098 increases the frictional force between the inner surface of the sponge 43 inserted into the shaft body 409 of the support shaft 40 and the outer surface of the shaft body 409, and can prevent the sponge 43 from slipping and rotating on the non-rotating shaft body 409 during wafer cleaning. Note that FIG. 5 shows a state in which the reduced-diameter portion 400 (see FIG. 3), which is one end side of the support shaft 40, has entered the insertion hole 511 of the support wall 510 of the first support portion 51, and the other end side supported by the second support portion 52 of the support shaft 40 is in a state where the knock pin 524 of the second support portion 52 described later is not in contact.

[0044] The second support portions 52 are respectively disposed on the respective extending portions 4491 at a predetermined distance horizontally apart so as to face the support wall 510 of the first support portion 51 erected on the base portion 4490 of the support plate 449 shown in FIGS. 3 and 5.

[0045] For example, as shown in FIG. 6, on the other end side of the support shaft 40, a pin pressing contact hole 4008 having an inverted conical surface that gradually reduces in diameter toward one end side inside the support shaft 40 and with which the conical surface of the tip of the conical frustum-shaped knock pin 524 of the second support portion 52 described later abuts is formed. Note that the tip of the knock pin 524 may be spherical, and the other end of the support shaft 40 may be an inverted spherical surface. Further, the tip of the knock pin 524 is not limited to a conical surface or a spherical surface, and may include a convex portion disposed at the center and an annular plane surrounding the convex portion. The other end of the support shaft 40 may be formed with a concave portion into which the convex portion enters. Also, a concave portion may be formed at the tip of the knock pin 524, and a convex portion may be formed at the other end of the support shaft 40.

[0046] The second support portion 52 shown in FIGS. 3, 5, and 6 includes a support block 520 having a substantially rectangular parallelepiped shape, and a knock pin 524 having a tip (a frustum-shaped tip) that abuts against a pin abutting hole 4008 of the support shaft 40 shown in FIG. 6.

[0047] The support block 520 is removably fixed to the upper surface of the extension portion 4491 by, for example, two fixing bolts 5208. That is, as shown in FIG. 7, two bolt insertion holes 5203 penetrating from the upper surface to the lower surface are formed on both the left and right sides of the support block 520, and a fixing bolt 5208 inserted into the support block 520 by overlapping the bolt insertion holes 5203 with screw holes (not shown) formed on the upper surface of the extension portion 4491 shown in FIG. 3 is screwed into the screw holes (not shown), whereby the support block 520 can be bolt-fixed on the extension portion 4491. Note that the fixing of the support block 520 on the extension portion 4491 may be realized by disposing a push-in type one-touch lock or the like on the lower surface of the support block 520 instead of by bolt fixing.

[0048] The knock pin 524 shown in FIGS. 3, 5, and 6 has a substantially T-shaped overall shape in plan view, and includes a push knob 5246 that is on the rear end side and has the largest diameter in the entire knock pin 524, a pin base portion 5247 that is integrally formed with the push knob 5246 and has a smaller diameter than the push knob 5246, and a tapered abutting portion 5248 that is integrally formed with the pin base portion 5247, is on the front end side, has a larger diameter than the pin base portion 5247, and gradually decreases in diameter toward the tip and has a frustum shape.

[0049] As shown in FIGS. 5 and 6, a substantially annular plate-shaped biasing force transmission plate 5245, a part of which is cut out so as to be insertable into the pin base portion 5247 from the outer surface side, is attached to the pin base portion 5247. The front surface of the biasing force transmission plate 5245 formed to have a larger diameter than the maximum diameter of the tapered abutting portion 5248 is separably abutted against the base rear surface of the tapered abutting portion 5248. Further, the rear surface of the biasing force transmission plate 5245 is connected to one end side of a compression spring 53 inserted through the pin base portion 5247.

[0050] A compression spring 53, which is an example of a biasing member, is, for example, a coil spring, has a larger diameter than the pin base 5247, and the pin base 5247 is inserted through its central hole. For example, two columnar catching protrusions 5243 are formed on the outer surface of the pin base 5247 with a 180-degree gap in the circumferential direction of the pin base 5247. The compression spring 53 is capable of expanding and contracting between the catching protrusions 5243 and the biasing force transmission plate 5245.

[0051] As shown in FIG. 7, on the upper side of the support block 520, a pin insertion hole 521 having a substantially circular front view is formed to penetrate from one side surface 5206 closer to the support shaft 40 toward the other side surface 5207. The pin insertion hole 521 is provided with a stepped surface 5215 whose diameter is reduced in one step from one side surface 5206 toward the other side surface 5207. Further, around the pin insertion hole 521 on one side surface 5206, two catching grooves 5216 are formed so as to face each other in the lateral direction of the support block 520. The catching grooves 5216 have, for example, groove bottoms extending from the outer periphery of the pin insertion hole 521 to both outer sides and for catching the catching protrusions 5243.

[0052] From the center of the upper surface of the support block 520 to the pin insertion hole 521, one protrusion passing groove 5219 through which the catching protrusion 5243 can pass is formed by being notched in the Z-axis direction, and the groove bottom of the protrusion passing groove 5219 is located at a position below the pin insertion hole 521 having a circular front view.

[0053] As shown in FIG. 3, a state where the sponge 43 is supported by the support shaft 40 in the cleaning device 4 and can be used for wafer cleaning will be described. The sponge 43 is inserted and fixed into the shaft body 409 of the support shaft 40 shown in FIG. 5. One end side of the sponge 43 abuts against the back side of the lock plate 571. Further, in the support shaft 40, the reduced-diameter portion 400 at one end side and the O-ring 401 (see FIG. 3) are fitted into the insertion hole 511 of the first support portion 51, and as shown in FIG. 8, the positioning projection 572 formed on the support wall 510 of the first support portion 51 is fitted into any one of the notch grooves 5711 of the lock plate 571. Then, the support shaft 40 and the sponge 43 extend on the support plate 449 from the base portion 4490 toward the extending portion 4491.

[0054] The conical table-shaped taper abutting portion 5248 at the tip side of the knock pin 524 enters and abuts against the inverted conical surface of the pin abutting hole 4008 at the other end side of the support shaft 40 shown in FIG. 6. At the same time, the front surface of the biasing force transmission plate 5245 that also acts as a fastener abuts against the other end surface of the sponge 43 and the other end surface of the support shaft 40. On the support plate 449, the support shaft 40 and the sponge 43 are fixed in a hollow manner by the support mechanism 5 as shown in FIG. 3. Note that the sponge 43 is regulated by the spiral anti-slip groove 4098 formed on the outer surface of the support shaft 40, the biasing force transmission plate 5245 that receives the biasing force of the compression spring 53, and the lock plate 571 so as not to shift in the extending direction on the support shaft 40 and not to rotate on the support shaft 40.

[0055] The catching projection 5243 of the knock pin 524 with the pin base 5247 inserted into the pin insertion hole 521 of the support block 520 of the second support portion 52 shown in FIGS. 6 and 9 is caught so as to fit into the catching groove 5216 of the support block 520. The compression spring 53 is contracted between the catching projection 5243 and the biasing force transmission plate 5245 and is shorter than its natural length. Then, due to the biasing force by which the compression spring 53 tends to extend to its natural length, the support shaft 40 is biased from one second support portion 52 toward the other first support portion 51 via the biasing force transmission plate 5245, and the support shaft 40 and the sponge 43 inserted into the support shaft 40 are fixedly held in a hollow manner between the second support portion 52 and the other first support portion 51 as shown in FIG. 3. Further, the support shaft 40 is prevented from rotating above the support plate 449 because the positioning projection 572 formed on the support wall 510 of the first support portion 51 shown in FIG. 8 fits into any one of the notch grooves 5711 of the lock plate 571. Also, as shown in FIGS. 3 and 9, the push knob 5246 of the knock pin 524 is positioned outside the support block 520.

[0056] For example, the cleaning device 4 in the present embodiment constitutes a cleaning water supply mechanism 46 and includes a water reservoir 467 shown in FIGS. 3, 4, and 5 in which the lower side of the roll-shaped sponge 43 is submerged. The water reservoir 467 is disposed, for example, in a region between the first support portion 51 and the second support portion 52 on the support plate 449 and is a shallow case in the shape of a rectangular parallelepiped in plan view extending with a length greater than the length of the sponge 43 that is supported in a hollow manner.

[0057] Most of the sponge 43 other than the lower part is exposed in the water reservoir 467 so that the sponge 43 can rotate in the water reservoir 467. The water reservoir 467 is composed of, for example, a substantially rectangular bottom plate 4671, two side plates 4672 (only shown in FIG. 5) facing each other in the extending direction of the water reservoir 467, and two side plates 4673 and 4674 facing each other in the width direction. As shown in FIG. 4, the side plate 4674 is erected so as to incline outward with respect to the side plate 4673 erected vertically from the bottom plate 4671. When the cleaning water accumulated in the water reservoir 467 rotates together with the support plate 449 and then suddenly stops, for example, it is likely to jump out of the water reservoir 467 and be discharged.

[0058] Hereinafter, the operation of the grinding device 1, and particularly the operation of the cleaning device 4, when the upper surface 903 of the wafer 90 is ground using the grinding device 1 shown in FIG. 1 above and then the lower surface 900 of the wafer 90 (in this embodiment, the protective tape 91 attached to the lower surface 900) is cleaned will be described in detail.

[0059] In the grinding process, first, the turntable 17 shown in FIG. 1 rotates, so that the chuck table 18 in a state where the wafer 90 is not placed revolves, and the chuck table 18 moves to the vicinity of the first holding mechanism 41. The robot 157 pulls out a single wafer 90 from the first cassette 154 and moves the wafer 90 to the temporary placement area 152. Next, after the wafer 90 is centered by the alignment unit 153, the first holding mechanism 41 moves the centered wafer 90 onto the chuck table 18. Then, after the wafer 90 is placed on the holding surface 180 with the upper surface 903 facing upward so that the center of the chuck table 18 and the center of the wafer 90 are substantially aligned, the chuck table 18 that transmits the suction force generated by a suction source (not shown) sucks and holds the wafer 90 on the holding surface 180.

[0060] Next, the turntable 17 shown in FIG. 1 rotates in the counterclockwise direction as viewed from the +Z direction, so that the chuck table 18 holding the wafer 90 by suction is aligned with the rough grinding wheel 306 of the rough grinding unit 30 and the wafer 90 held on the chuck table 18. The alignment is performed, for example, such that the rotation center of the grinding wheel 304 is displaced horizontally by a predetermined distance with respect to the rotation center of the wafer 90, and the rotation locus of the rough grinding wheel 306 passes through the rotation center of the wafer 90. Further, as the motor 302 rotates the spindle 300, the grinding wheel 304 rotates at a predetermined rotational speed.

[0061] The rough grinding feed unit 39 lowers the rough grinding unit 30 at a predetermined feed rate, and the upper surface 903 of the wafer 90 is ground by the rotating rough grinding wheel 306. Further, as the chuck table 18 rotates at a predetermined rotational speed, the wafer 90 held on the holding surface 180 also rotates, so that the rough grinding wheel 306 performs rough grinding on the entire upper surface 903 of the wafer 90. During the rough grinding process, grinding water is supplied to the contact portion between the rough grinding wheel 306 and the upper surface 903 of the wafer 90, and the contact portion is cooled and cleaned.

[0062] While the thickness of the wafer 90 is being measured by the thickness measuring gauge 38 shown in FIG. 1, after the wafer 90 is rough ground up to just before the finish thickness, the rough grinding feed unit 39 raises the rough grinding unit 30 and separates it from the wafer 90. Then, the turntable 17 shown in FIG. 1 rotates in the counterclockwise direction as viewed from the +Z direction, and the chuck table 18 that holds the wafer 90 by suction moves below the finish grinding unit 31, and the finish grinding of the wafer 90 by the finish grinding unit 31 is performed in substantially the same manner as the rough grinding. Then, when the wafer 90 is ground to the finish thickness, the finish grinding unit 31 separates from the upper surface 903 of the wafer 90.

[0063] Next, as the turntable 17 shown in FIG. 1 rotates, the chuck table 18 that sucks and holds the wafer 90 moves to the vicinity of the second holding mechanism 42. Then, the horizontal movement unit 423 pivots and moves the holding pad 420 in the horizontal direction to position the holding pad 420 above the wafer 90 such that the center of the upper surface 903 of the wafer 90 and the center of the holding pad 420 are substantially aligned. Further, the vertical movement unit 421 lowers the holding pad 420 to bring the holding surface 426 into contact with the upper surface 903 of the wafer 90. In this state, the suction source 4298 (see FIG. 2) generates a suction force, and the holding pad 420 sucks and holds the wafer 90 with the holding surface 426. Next, the suction and holding of the wafer 90 by the chuck table 18 is released, and the holding pad 420 that holds the upper surface 903 of the wafer 90 by the vertical movement unit 421 rises, and the wafer 90 is carried out from the chuck table 18 by the second holding mechanism 42.

[0064] Next, a process of cleaning the lower surface 900 of the wafer 90 (in this embodiment, the protective tape 91 attached to the lower surface 900) held by the second holding mechanism 42 using the sponge 43 of the cleaning device 4 will be described.

[0065] First, the wafer 90 held by the second holding mechanism 42 is positioned on the three sponges 43 shown in FIGS. 1, 2, and 3 (only one is shown in FIG. 2), and the outer surface of the sponge 43 is brought into contact with the protective tape 91 on the lower surface 900 of the wafer 90. That is, the horizontal movement unit 423 shown in FIG. 1 pivots and moves the holding pad 420 holding the wafer 90 in the horizontal direction to position the wafer 90 above the cleaning device 4. This positioning is performed such that, for example, the center of the protective tape 91, whose center substantially coincides with the center of the wafer 90 on the axis line of the rotating shaft 480 shown in FIGS. 3 and 10, approximately overlaps. In FIG. 2, which shows the state of cleaning the protective tape 91, the moving mechanism 48 that relatively moves the sponge 43 and the second holding mechanism 42 in a direction intersecting the extending direction of each sponge 43 shown in detail in FIG. 3 is shown in a simplified manner, and the support mechanism 5 and the support plate 449 are omitted. Also, in FIG. 2, only one of the three sponges 43 in contact with the protective tape 91 of the wafer 90 is shown.

[0066] Next, the holding pad 420 is lowered by the vertical movement unit 421 shown in FIGS. 1 and 2, and only the outer surfaces on the +Z direction side of the three sponges 43 come into contact with the protective tape 91 shown in FIG. 10 adhered to the lower surface 900 of the wafer 90. A part of the outer surfaces of the three sponges 43 on the +Z direction side is crushed by a predetermined amount of the sponge crushing allowance L1 shown in FIG. 4, and this part becomes a rectangular parallelepiped shape in plan view and contacts the lower surface of the protective tape 91 from the center region to the outer peripheral edge following the lower surface of the protective tape 91. The height positions of the three sponges 43 are set so that the upper surfaces of the first support portion 51 and the second support portion 52 do not come into contact with the protective tape 91.

[0067] Before the sponge 43 contacts the protective tape 91 adhered to the lower surface of the wafer 90, the cleaning water sent from the cleaning water supply source 469 by the cleaning water supply mechanism 46 shown in FIG. 3 in advance passes through the water flow path 4801 inside the shaft of the rotating shaft 480, inside the first support portion 51, the insertion hole 511 of the first support portion 51, the flow path 408 of the support shaft 40 communicating with the insertion hole 511, and the water supply hole 407 of the support shaft 40 and is supplied to the three sponges 43 respectively. Therefore, since the sponge 43 contains cleaning water and is sufficiently swollen and elastic, it can be brought into contact with the protective tape 91 adhered to the lower surface 900 of the wafer 90 following it sufficiently. That is, since the sponge 43 is not dried and hardened, the cleaning is not insufficient, and the protective tape 91 is not damaged by the dried sponge 43.

[0068] The cleaning water oozes out over a wide area on the outer surface which is the portion contacting the protective tape 91 from inside the sponge 43. Note that if the cleaning water supplied from the cleaning water supply mechanism 46 to the sponge 43 overflows in an excessive amount from the outer surface of the sponge 43, the wafer 90 and the protective tape 91 may float up from the outer surface of the sponge 43 due to the cleaning water, and the cleaning of the protective tape 91 by the sponge 43 may become insufficient. The supply amount of the cleaning water per unit time supplied from the cleaning water supply mechanism 46 to the three sponges 43 is appropriately adjusted so that such a situation does not occur.

[0069] In this state, as the rotating shaft 480 is rotationally driven by the shaft rotation mechanism 481 of the moving mechanism 48 shown in FIGS. 2 and 3, together with the support plate 449, the three sponges 43 shown in FIG. 10 inserted into the three support shafts 40 respectively orbit in the horizontal plane. Note that the sponge 43 does not rotate about the support shaft 40. And, while the portion of the outer surface of each sponge 43 facing the +Z direction side and having a rectangular shape in plan view following the protective tape 91 discharges the cleaning water, the protective tape 91 attached to the lower surface 900 of the wafer 90 held by the second holding mechanism 42 shown in FIG. 2 is being cleaned. That is, while the three sponges 43 orbit in the horizontal plane, the protective tape 91 of the wafer 90 held by the second holding mechanism 42 is being cleaned. As a result, dirt such as grinding debris adhering to the protective tape 91 is rubbed by the three sponges 43 and is also washed away by the cleaning water. Note that since cleaning water continuously oozes out from the inside toward the outer surface of the sponge 43, the dirt such as grinding debris adhering to the outer surface of the sponge 43 falls off the sponge 43 and flows down to a water case (not shown) provided at the location where the cleaning device 4 is disposed in FIG. 1.

[0070] In the present embodiment, the moving mechanism 48 that relatively moves the sponge 43 and the second holding mechanism 42 in a direction intersecting the extending direction of the sponge 43, for example, realizes the relative movement by orbiting the three sponges 43 by the rotating shaft 480 and the shaft rotation mechanism 481 with the protective tape 91 of the wafer 90 in contact with the three sponges 43. Note that when cleaning the protective tape 91 attached to the lower surface 900 of the wafer 90, the holding pad 420 holding the wafer 90 may be reciprocated in the horizontal direction with the rotating shaft 480 rotationally driven. For example, when the sponge 43 shown in FIGS. 2 and 10 is a roll sponge extending with a length equal to or greater than the diameter of the wafer 90, in such a case, with respect to one roll sponge extending with a length equal to or greater than the diameter, the wafer 90 is linearly moved in the X-axis direction or the Y-axis direction in the horizontal plane by the moving mechanism, and the protective tape 91 may be brought into contact with the roll sponge for cleaning. Or, the roll sponge side may linearly move in the horizontal plane to contact the protective tape 91 for cleaning. In addition, the wafer 90 may be pivotally moved in the horizontal plane by the moving mechanism.

[0071] As in this embodiment, the cleaning water supply mechanism 46 supplies cleaning water to the inside of the support shaft 40 and discharges it from the outer surface of the sponge 43, so that it is possible to supply cleaning water evenly to the entire sponge 43. Note that the cleaning water supply mechanism 46 may be configured to supply the cleaning water jetted from an external nozzle to the contact portion between the sponge 43 and the protective tape 91.

[0072] In this way, when cleaning the wafer 90, the sponge 43 is not rotated about the support shaft 40, and a part of the outer peripheral surface of the three roll-shaped sponges 43 that orbit in the horizontal plane is brought into contact with the wafer 90 for cleaning. Therefore, unlike the conventional method, the dirt that has flowed down to the lower side surface of the sponge 43 due to the rotation of the sponge 43 about the support shaft does not move back to the upper side surface and reattach dirt to the wafer 90.

[0073] After the cleaning of the protective tape 91 adhered to the lower surface 900 of the wafer 90 is completed after a predetermined time has elapsed, the second holding mechanism 42 shown in FIGS. 1 and 2 conveys the wafer 90 to the spinner cleaning mechanism 156 shown in FIG. 1. After the upper surface 903 of the wafer 90 is cleaned in the spinner cleaning mechanism 156, the robot 157 loads the wafer 90 into the second cassette 155.

[0074] As described above, when cleaning the protective tape 91 attached to a plurality of wafers 90 continuously using a portion on the +Z direction side of the outer surface of three sponges 43 (see FIGS. 4 and 10), even if cleaning water is supplied from the inside of the sponge 43 to the outer surface, dirt such as grinding chips may adhere to such a portion to an unacceptable level. Therefore, it becomes necessary to switch the portion of the crushing margin L1 shown in FIG. 4, which is the portion of the sponge 43 that contacts the protective tape 91. Hereinafter, the case where an operator removes the support shaft 40 from the support mechanism 5 shown in FIGS. 9 and 10 and rotates the support shaft 40 by the rotation angle determining portion 57 of the support mechanism 5 to switch the portion where the sponge 43 contacts the protective tape 91 of the wafer 90 will be described.

[0075] As a timing for performing the above switching, for example, there is a stage where grinding and cleaning of all the wafers 90 (for example, 25 wafers 90) in the first cassette 154 shown in FIG. 1 are completed. Each component of the grinding apparatus 1 and the cleaning apparatus 4 shown in FIG. 1 are temporarily stopped, for example. Thereafter, the operator pushes the push knob 5246 of the knock pin 524 toward the support shaft 40 with respect to the support mechanism 5 that supports the sponge 43 in a state where it can clean the protective tape 91 on the lower surface 900 of the wafer 90, as shown in FIGS. 3, 9, and 10. As a result, as shown in FIG. 11, the compression spring 53 contracts from the state shown in FIG. 9, and the two catching protrusions 5243 of the knock pin 524 come out of the catching groove 5216 of the support block 520. Further, with the knock pin 524 pushed toward the support shaft 40, by rotating the push knob 5246 90 degrees when viewed from the back side, the two catching protrusions 5243 of the knock pin 524 are displaced 90 degrees from the catching groove 5216 of the support block 520 and face the protrusion passing groove 5219 of the support block 520.

[0076] When the operator releases the pushing of the knock pin 524, the compression spring 53 that had been contracted between the catching protrusion 5243 and the back surface of the biasing force transmission plate 5245 repels against the biasing force transmission plate 5245 to return to its natural length. As shown in FIG. 12, the knock pin 524 moves outward, and the catching protrusion 5243 passes through the protrusion through groove 5219 outward. The other end side of the compression spring 53 extends outward from the pin insertion hole 521 and contacts and stops at the stepped surface 5215 (see FIG. 7), so that the knock pin 524 will not come off the support block 520 forcefully.

[0077] As a result, the frustum-shaped taper pressing portion 5248 at the tip side of the knock pin 524 that had been in contact with the conical surface of the pin pressing hole 4008 (see FIG. 6) at the other end side of the support shaft 40 comes out of the pin pressing hole 4008 as shown in FIG. 12. Also, the front surface of the biasing force transmission plate 5245 moves away from the other end surface of the sponge 43 and the other end surface of the support shaft 40. In this way, the support with the biasing of the support shaft 40 by the compression spring 53 can be easily released, and the support shaft 40 can be made removable from the support mechanism 5.

[0078] Next, as shown in FIG. 13, the operator slightly pulls the support shaft 40 inserted into the sponge 43 together with the sponge 43 in a direction away from the first support portion 51, so that the reduced diameter portion 400 of the support shaft 40 and the O-ring 401 inserted into the insertion hole 511 of the support wall 510 of the first support portion 51 come out of the insertion hole 511. Also, the positioning protrusion 572 formed on the support wall 510 comes out of one of the notch grooves 5711 of the lock plate 571, and the lock plate 571 becomes rotatable about the support shaft 40 as a rotation axis.

[0079] In this state, as shown in FIG. 14, the operator rotates the support shaft 40, for example, 45 degrees in this embodiment, so that the soiled area in the outer surface of the sponge 43 that had been facing the +Z direction is shifted by 45 degrees from the +Z direction, and the adjacent non-soiled area in the outer surface of the sponge 43 faces the +Z direction.

[0080] Next, the operator moves the support shaft 40 and the sponge 43 closer to the first support portion 51 again, so that the positioning projection 572 of the first support portion 51 fits into the notch groove 5711 of the lock plate 571 (the notch groove 5711 located adjacent to the previously fitted notch groove 5711), and the reduced-diameter portion 400 of the support shaft 40 and the O-ring 401 are inserted into the insertion hole 511.

[0081] Next, when the operator pushes the push knob 5246 of the knock pin 524 shown in FIG. 12 toward the support shaft 40, the two catching projections 5243 pass through the projection passage groove 5219 toward the inside, and the tapered pressing portion 5248 (see FIG. 6) on the tip side of the knock pin 524 enters the pin pressing hole 4008. Here, due to the action of the conical surface of the tapered pressing portion 5248, even if there is a slight deviation between the center of the support shaft 40 and the center of the knock pin 524 by removing the support shaft 40 and switching the cleaning surface of the sponge 43 in the above series of operations, a guide is provided to return them to coincide with the center.

[0082] As a result of the operator pushing the knock pin 524, the tapered pressing portion 5248 on the tip side of the knock pin 524 enters and abuts against the reverse conical surface of the pin pressing hole 4008 on the other end side of the support shaft 40, and the front surface of the biasing force transmission plate 5245 shown in FIGS. 6 and 9 abuts against the other end surface of the sponge 43 and the end surface of the other end of the support shaft 40. When this state is reached, the catching projection 5243 of the knock pin 524 is located closer to the support shaft 40 side than the catching groove 5216. Also, the compression spring 53 is contracted between the biasing force transmission plate 5245 and the catching projection 5243 to store the biasing force.

[0083] After that, when the operator rotates the knock pin 524 by 90 degrees, the two catching protrusions 5243 are displaced by 90 degrees from the protrusion through groove 5219 of the support block 520 and face the two catching grooves 5216 of the support block 520 respectively. Next, when the operator gradually releases the pressing of the knock pin 524, the two catching protrusions 5243 are caught by the two catching grooves 5216, and the compression spring 53 in a state of being contracted from its natural length biases the support shaft 40 via the biasing force transmission plate 5245 from one second support portion 52 toward the other first support portion 51 (the state shown in FIGS. 6 and 9), and the sponge 43 inserted into the support shaft 40 faces the new outer surface that is not dirty on the +Z direction side, and the state shown in FIGS. 3 and 10 in which the lower surface 900 of the wafer 90 can be cleaned is achieved.

[0084] As described above, a cleaning device according to the present invention that brings a part of the outer surface of a roll-shaped sponge 43 that does not rotate freely into contact with a protective tape 91 attached to the lower surface 900 of a wafer 90 and relatively moves the wafer 90 and the sponge 43 in a direction intersecting the extending direction of the sponge 43 to clean the protective tape 91 includes a support shaft 40 extending in a direction parallel to the protective tape 91 attached to the lower surface 900 of the wafer 90 held by the second holding mechanism 42, a sponge 43 having an insertion hole into which the support shaft 40 is inserted, and a support mechanism 5 that supports the support shaft 40. The support mechanism 5 includes a first support portion 51 that supports one end side of the support shaft 40 and a second support portion 52 that supports the other end side of the support shaft 40. The support mechanism 5 is disposed between the first support portion 51 and the second support portion 52 and includes a compression spring 53 that biases the support shaft 40 from one second support portion 52 toward the other first support portion 51. By this, the detachment and attachment of the support shaft 40 with the sponge 43 inserted thereinto between the first support portion 51 and the second support portion 52 are facilitated by the compression spring 53, and the replacement of the sponge 43 and the switching of the cleaning surface that contacts the protective tape 91 of the sponge 43 can be easily performed in a short time, so that a situation in which the grinding process in the grinding device 1 is stagnated for a long time due to wafer cleaning being a bottleneck can be prevented.

[0085] Also, for example, the support mechanism 5 shown in FIG. 3 includes a rotation angle determination unit 57 that enables the support shaft 40 to rotate intermittently at a preset rotation angle. By rotating the support shaft 40 by the rotation angle determination unit 57, it is possible to switch the cleaning surface where the sponge 43 contacts the protective tape 91 of the wafer 90. That is, when cleaning the protective tape 91, the sponge 43 is not rotated about the support shaft 40, but a part of the roll-shaped sponge 43 is brought into contact with the protective tape 91 for cleaning. Thus, unlike the conventional case, the situation where the dirt flowing down the lower side surface of the sponge 43 is rotated and moved again to the upper side surface and reattached to the protective tape 91 due to the rotation of the sponge 43 about the support shaft 40 does not occur. In the present embodiment, eight notch grooves 5711 of the lock plate 571 constituting the rotation angle determination unit 57 are formed at intervals of 45 degrees in the circumferential direction, so that the cleaning surface of the sponge 43 can be used by dividing it into a total of eight surfaces from the dirty cleaning surface to the clean cleaning surface. Also, it is possible to replace the sponge 43 etc. without using a special tool. Furthermore, only the sponge 43 is required for the parts that need to be maintained regularly.

[0086] In the cleaning device 4 shown in FIG. 3 in the present embodiment, while cleaning water is being supplied from the cleaning water supply mechanism 46 to the sponge 43 while cleaning the protective tape 91 on the lower surface 900 of the wafer 90, it is preferable to supply cleaning water from the cleaning water supply mechanism 46 to the sponge 43 not only during the cleaning operation but also during the standby period of the cleaning device 4 when the wafer 90 is not being cleaned, in order to prevent the sponge 43 from drying. Note that the amount of cleaning water used is set to be less than the amount in the case of cleaning the wafer as described above.

[0087] For example, assume a situation where the grinding device 1 has finished grinding a plurality of wafers 90 and the grinding device 1 stops, for example, when the date for grinding the previous wafer 90 and the next wafer 90 is different. As shown in FIGS. 3 and 4, the cleaning device 4 in this embodiment constitutes a cleaning water supply mechanism 46 and includes a water sump 467 in which the lower side of the roll-shaped sponge 43 is submerged. Therefore, the water sump 467 may accumulate the cleaning water that oozes from the sponge 43 and is used for cleaning the protective tape 91. Since this cleaning water may be dirty, it is necessary to drain it from the water sump 467.

[0088] Specifically, when the cleaning of the protective tape 91 adhered to the lower surface 900 of the last wafer 90 is completed, the cleaning water accumulated in the water sump 467 that rotates together with the support plate 449 by the shaft rotation mechanism 481 shown in FIG. 3 of the cleaning device 4 is subjected to inertial force due to the sudden stop of the rotation by the shaft rotation mechanism 481, and jumps out and is discharged from the side plate 4674 erected so as to incline outward.

[0089] Thereby, after the inside of the water sump 467 is emptied once, the clean cleaning water that further oozes from the sponge 43 that has been supplied from the cleaning water supply mechanism 46 and the cleaning of the protective tape 91 has been stopped is stored in the water sump 467. The clean cleaning water newly stored in this water sump 467 prevents the sponge 43 from drying even during the period when the wafer 90 is not being ground by the grinding device 1 and is stopped. It is preferable that the cleaning water supply mechanism 46 continuously supplies a small amount of cleaning water to the sponge 43 during this period.

[0090] It goes without saying that the cleaning device 4 according to the present invention is not limited to the above embodiment, and may be implemented in various different forms within the scope of its technical idea. Also, each step of grinding the wafer 90 and each step of cleaning the protective tape 91 can be appropriately changed within the range where the effects of the present invention can be exhibited. For example, the protective tape 91 of the wafer 90 before grinding may be cleaned by the cleaning device 4.

[0091] For example, in the embodiment described above, as an example, at the timing when the grinding / washing of all the wafers 90 in the first cassette 154 shown in FIG. 1 is completed, the operator rotates the support shaft 40 by the rotation angle determining unit 57 to create a washing surface that contacts the protective tape 91 of the sponge 43, and the washing surface where the sponge 43 contacts the protective tape 91 is switched. However, for example, the washing surface of the sponge 43 may be automatically switched by the washing device 4 for each ground wafer 90. When performing this automatic switching, it is preferable to do so without supplying washing water to the sponge 43. And in this case, for example, the first support portion 51 or the second support portion 52 of the support mechanism 5 is provided with a ratchet mechanism 58 shown in FIG. 15, which functions as a rotation angle determining unit in a form different from the rotation angle determining unit 57 including the lock plate 571 and the positioning projection 572 shown in FIG. 3.

[0092] The ratchet mechanism 58 shown in FIG. 15 includes, for example, a gear 580 disposed on the support wall 510 of the first support portion 51, and a stopper 583 rotatable about the stopper shaft 582. One end side of the support shaft 40 is connected to the gear 580, for example.

[0093] As shown in FIGS. 2 and 10, when cleaning the protective tape 91 adhered to the lower surface 900 of the wafer 90, the horizontal movement unit 423 shown in FIG. 1 rotates the holding pad 420 holding the wafer 90 in the horizontal direction to position the wafer 90 above the cleaning device 4. This positioning is performed, for example, so that the center of the protective tape 91 approximately overlaps the axis line of the rotating shaft 480 shown in FIGS. 3 and 10. The sponge 43 shown in FIG. 16 (only one of the three in contact with the protective tape 91 is shown in FIG. 16) orbits in the horizontal plane together with the support plate 449 as the rotating shaft 480 is rotationally driven by the shaft rotation mechanism 481 of the movement mechanism 48. Note that the sponge 43 does not rotate about the support shaft 40. And the region facing the +Z direction side of the outer surface of each sponge 43 and having a rectangular shape in plan view following the protective tape 91 cleans the protective tape 91 adhered to the lower surface 900 of the wafer 90 held by the second holding mechanism 42 while discharging the cleaning water. Let the movement direction of the sponge 43 shown in FIG. 16 in this case be R1.

[0094] The ratchet mechanism 58 shown in FIG. 16 does not rotate the support shaft 40 into which the sponge 43 is inserted in the movement direction R1 of the sponge 43 with respect to the protective tape 91 of the wafer 90 held by the second holding mechanism 42 when cleaning the protective tape 91 adhered to the lower surface 900 of the wafer 90. That is, as shown in FIGS. 15 and 16, during the cleaning of the protective tape 91, a force is applied to rotate the gear 580 of the ratchet mechanism 58 in the direction of arrow W1 shown in FIG. 15 (counterclockwise when viewed from the front side of the paper surface), but since the stopper 583 locks the gear 580, the gear 580 and the support shaft 40 do not rotate. Therefore, the cleaning surface on the +Z direction side of the sponge 43 into which the support shaft 40 is inserted does not change.

[0095] When the cleaning of the protective tape 91 of one wafer 90 is completed and it is necessary to switch the portion of the sponge 43 that contacts the protective tape 91 of the wafer 90 to be cleaned next, for example, the horizontal movement unit 423 shown in FIG. 1 pivots the holding pad 420 holding the next wafer 90 horizontally to position the next wafer 90 above the cleaning device 4. This positioning is performed, for example, such that the center of the protective tape 91 approximately overlaps the axis line of the rotating shaft 480 shown in FIGS. 3 and 10. Note that this positioning may be performed such that the radius of the protective tape 91 approximately overlaps only one of the three sponges 43.

[0096] Next, the holding pad 420 is lowered by the vertical movement unit 421 shown in FIG. 1, and only the outer surface of the sponge 43 contacts the protective tape 91 attached to the lower surface 900 of the wafer 90. A portion of the outer surface of the sponge 43 on the +Z direction side is crushed by a predetermined amount corresponding to the sponge crushing margin, and this portion becomes a rectangular parallelepiped shape in plan view and contacts the lower surface of the protective tape 91 from the substantially central region to the substantially outer peripheral edge following the lower surface of the protective tape 91. Note that the height position of the sponge 43 is set so that the upper surface of the first support portion 51 does not contact the protective tape 91.

[0097] As the sponge 43 shown in FIG. 17 moves in a circular motion within a horizontal plane together with the support plate 449 as the rotating shaft 480 is rotationally driven (stepwise rotation drive) by a predetermined angle by the shaft rotation mechanism 481 of the moving mechanism 48. Here, the rotation direction of the rotating shaft 480 by the shaft rotation mechanism 481 is opposite to the rotation direction when the protective tape 91 was cleaned as described above, and the moving direction of the sponge 43 in this case is defined as the moving direction R2 shown in FIGS. 17 and 18(A) to (C).

[0098] When the sponge 43 moves in the moving direction R2, which is the direction opposite to the moving direction R1 of the sponge 43 with respect to the second holding mechanism 42 that holds the wafer 90 when cleaning the protective tape 91 adhered to the lower surface 900 of the wafer 90, the ratchet mechanism 58 can rotate the support shaft 40 to switch the contact surface where the sponge 43 contacts the protective tape 91 of the wafer 90. That is, as shown in FIGS. 18(A), (B), and (C), when switching the cleaning surface of the sponge 43, a force is applied to rotate the gear 580 of the ratchet mechanism 58 in the direction of arrow W2 (clockwise direction when viewed from the front side of the paper surface). As the gear 580 rotates in the direction of arrow W2, the stopper 583 is pushed upward and disengages from the tooth 5801 of the gear 580. Next, as the gear 580 rotates in the direction of arrow W2, the stopper 583 returns downward by its own weight and engages with the tooth 5802 adjacent to the tooth 5801 of the gear 580. When the step rotation of the rotating shaft 480 by the shaft rotation mechanism 481 of the moving mechanism 48 stops, the cleaning surface of the sponge 43 into which the support shaft 40 connected to the gear 580 is inserted is switched to a clean cleaning surface state.

[0099] For example, the switching of the cleaning surface of the sponge 43 may be performed by the horizontal movement unit 423 of the second holding mechanism 42 shown in FIG. 1 by positioning the protective tape 91 with respect to, for example, one of the sponges 43 that does not orbit around the holding pad 420 side. That is, for example, the alignment between the sponge 43 and the protective tape 91 is performed so that the radius of the protective tape 91 approximately overlaps only one of the three sponges 43. Then, the protective tape 91 brought into contact with one sponge 43 that is not orbiting by the moving mechanism 48 by the horizontal movement unit 423 may be moved in the moving direction corresponding to the direction in which the stopper 583 of the gear 580 of the ratchet mechanism 58 shown in FIGS. 18(A) to (C) can rotate for switching. It should be noted that the axis of the rotating shaft 480 may be aligned with the center of the wafer 90 held by the holding mechanism, the protective tape 91 may be brought into contact with the three sponges 43, and the rotating shaft 480 may be step-rotated by a predetermined angle to simultaneously rotate the three sponges 43 and switch to a clean cleaning surface.

[0100] Incidentally, for example, the sponge 43 is a roll sponge extending with a length equal to or greater than the diameter of the wafer 90. When the wafer 90 is linearly moved in the X-axis direction or the Y-axis direction in the horizontal plane by the moving mechanism with respect to the roll sponge extending with a length equal to or greater than the diameter, even when switching the cleaning surface with respect to the protective tape 91 of the roll sponge, the ratchet mechanism 58 does not rotate the support shaft 40 into which the sponge 43 is inserted in the moving direction of the second holding mechanism 42 holding the wafer 90 when cleaning the protective tape 91 adhered to the lower surface 900 of the wafer 90, and rotates the support shaft 40 in the direction opposite to the moving direction so that the portion where the sponge 43 contacts the wafer 90 can be switched.

Explanation of Signs

[0101] 90: Wafer 903: Upper surface of wafer 900: Lower surface of wafer 91: Protective tape 1: Grinding device 10: First device base 11: Second device base 150: First cassette mounting portion 151: Second cassette mounting portion 154: First cassette 155: Second cassette 157: Robot 153: Alignment means 152: Temporary placement area 156: Spinner cleaning mechanism 1561: Spinner table 12: First column 39: Rough grinding feed unit 30: Rough grinding unit 13: Second column 36: Finish grinding feed unit 31: Finish grinding unit 38: Thickness measurement gauge 17: Turntable 18: Chuck table 4: Cleaning device 40: Support shaft 400: Reduced diameter portion 401: O-ring 408: Flow path 407: Water supply hole 4008: Pin pressing hole 409: Shaft body 4098: Anti-slip groove 449: Support plate 4490: Base of the support plate 4491: Extension of the support plate 41: First holding mechanism 42: Second holding mechanism 420: Holding pad 426: Holding surface of the holding pad 429: Air flow path 4292: Air supply source 4298: Suction source 421: Vertical movement unit 423: Horizontal movement unit 424: Arm part 425: Swivel shaft part 43: Sponge 5: Support mechanism 51: First support part 510: Support wall 511: Insertion hole 52: Second support part 520: Support block 5206: One side surface of the support block 5207: The other side surface of the support block 5203: Bolt insertion hole 5208: Fixing bolt 521: Pin insertion hole 5215: Step surface 5216: Hook groove 5219: Protrusion passing groove 524: Knock pin 5246: Push knob 5247: Pin base 5248: Taper pressing part 5245: Biasing force transmission plate 5243: Hook protrusion 53: Compression spring 46: Cleaning water supply mechanism 469: Cleaning water supply source 467: Water sump 4671: Bottom plate 4674: Side plate 48: Moving mechanism 4801: Water flow path inside the shaft 480: Rotating shaft 481: Shaft rotation mechanism 57: Rotation angle determination part 571: Lock plate 5711: Notch groove 572: Positioning protrusion

Claims

1. A cleaning device that contacts a part of the outer surface of a non-rotatable roll-shaped sponge with the lower surface of a wafer, and relatively moves the wafer and the sponge in a direction intersecting the extending direction of the sponge to clean the lower surface of the wafer, comprising: a holding mechanism for holding the wafer; a support shaft extending in a direction parallel to the lower surface of the wafer held by the holding mechanism; the sponge having an insertion hole into which the support shaft is inserted; a support mechanism for supporting the support shaft; a cleaning water supply mechanism for supplying cleaning water to the sponge; and a moving mechanism for relatively moving the sponge and the holding mechanism in a direction intersecting the extending direction of the sponge. The support mechanism includes a first support portion that supports one end side of the support shaft and a second support portion that supports the other end side of the support shaft. An urging member is disposed between the first support portion and the second support portion and urges the support shaft from one of the first support portion and the second support portion toward the other support portion, and the cleaning device is such that the support shaft into which the sponge is inserted can be easily detached by the urging member.

2. The support mechanism includes a rotation angle determining portion that enables the support shaft to rotate intermittently at a preset rotation angle, and the cleaning device according to Claim 1, wherein the support shaft is rotated by the rotation angle determining portion to enable switching of the portion of the sponge that contacts the wafer.

3. The first support portion or the second support portion is provided with a ratchet mechanism that functions as the rotation angle determining portion, and the ratchet mechanism does not rotate the support shaft into which the sponge is inserted in the moving direction of the sponge with respect to the holding mechanism that holds the wafer when cleaning the lower surface of the wafer, and rotates the support shaft in the direction opposite to the moving direction to enable switching of the portion of the sponge that contacts the wafer. The cleaning device according to Claim 2.

4. A rotating shaft extending in a direction perpendicular to the lower surface of the wafer held by the holding mechanism and a shaft rotating mechanism for rotating the rotating shaft are provided, and the support shaft according to Claim 1, Claim 2, or Claim 3 is arranged so as to extend horizontally in a plurality of directions perpendicular to the rotating shaft and outward from the rotating shaft. ​ ​ ​ ​

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