Chuck table for suction holding of plate-shaped workpiece, machining device equipped with chuck table, and machining method for plate-shaped workpiece using machining device

Abstract

To ensure that processed waste does not remain on a washed holding surface, in a processing device that holds a plate-like workpiece with warpage on the holding surface and grinds it with a grinding stone.SOLUTION: A chuck table 3 has a holding surface 342 for suction-holding an under surface of a plate-like workpiece 9 in which an outer periphery warps upward above its central portion. The chuck table 3 comprises: a plate-like plate sponge 35 having a plan view annular shape and an opening at the center; a sponge gripping part 36 for gripping an inner peripheral portion 354 of the plate sponge 35 below the holding surface 342 by making an opening center of the plate sponge 35 coincide with the center of the holding surface 342 and making an outer peripheral portion 357 of the plate sponge 35 project above the holding surface 342; and an annular sponge suction port 32 for sucking the under surface of the outer peripheral portion 357 of the plate sponge 35 which is disposed outside the outer periphery of the holding surface 342 and is projecting above the holding surface 342. The sponge suction port 32 sucks the under surface of the plate sponge 35 and pulls down the plate sponge 35 to a position of the holding surface 342 or lower.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a chuck table that suction-holds a plate-shaped workpiece, a processing device equipped with the chuck table, and a processing method for a plate-shaped workpiece using the processing device. [Background technology]

[0002] The grinding device uses a grinding wheel to grind a plate-shaped workpiece held by the holding surface of the chuck table. The plate-shaped workpiece has, for example, a substrate with a resin layer formed in the center of the upper surface thereof, a protruding portion where the substrate protrudes outside the resin, and the outer periphery of the substrate is warped due to shrinkage when the resin hardens, etc.

[0003] When such a plate-shaped workpiece is held by suction on the holding surface, the conveying mechanism presses the plate-shaped workpiece against the holding surface so that the holding surface conforms to the warped outer peripheral portion of the plate-shaped workpiece, and then the holding surface is connected to a suction source to hold the plate-shaped workpiece by suction.

[0004] The chuck table prevents vacuum leakage from the outer periphery by contacting a ring-shaped sponge with the outer periphery of the lower surface of the plate-shaped workpiece, as disclosed in Patent Document 1. After grinding the workpiece, the plate-shaped workpiece is separated from the holding surface, and then the holding surface is cleaned with a brush (sponge cleaning) or two-fluid cleaning. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-207033 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the case of a chuck table that does not hold a plate-shaped workpiece by suction, the top of the sponge protrudes above the holding surface. Therefore, when cleaning the holding surface, the holding surface is surrounded by the sponge, which makes it difficult for cutting waste to flow off the holding surface and ends up remaining on the holding surface. If cutting waste remains on the holding surface, it will be caught between the bottom surface of the plate-shaped workpiece that the holding surface holds and the holding surface, causing the resin ground from the plate-shaped workpiece to have an uneven thickness.

[0007] Therefore, in a processing device in which a warped plate-shaped workpiece is held on a holding surface and is ground, for example, with a grinding wheel, there is a problem to be solved of how to prevent any machining debris from remaining on the cleaned holding surface. There is also a problem of providing a chuck table in the processing device whose holding surface is easy to clean. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides a chuck table having a holding surface that suction-holds the underside of a plate-shaped workpiece whose outer periphery is warped higher than the central portion, the chuck table comprising: an elastic plate member that is plate-shaped and annular in a plan view with an opening in the center; an elastic plate member gripping portion that aligns the center of the opening of the elastic plate member with the center of the holding surface, causing the outer periphery of the elastic plate member to protrude above the holding surface and gripping the inner periphery of the elastic plate member below the holding surface; and an annular elastic plate member suction port that is positioned outside the outer periphery of the holding surface and sucks in the underside of the outer periphery of the elastic plate member that protrudes above the holding surface, and the elastic plate member suction port is capable of sucking in the underside of the elastic plate member and pulling the elastic plate member down to a position below the holding surface.

[0009] In addition, the present invention, which solves the above-mentioned problems, is a chuck table having a holding surface that suction-holds the underside of a plate-shaped workpiece whose outer periphery is warped higher than the central portion, the chuck table comprising: an elastic plate member that is plate-shaped and annular in a plan view with an opening in the center; an elastic plate member gripping portion that aligns the center of the opening of the elastic plate member with the center of the holding surface, causing the inner periphery of the elastic plate member to protrude above the holding surface and gripping the outer periphery of the elastic plate member below the holding surface; and an annular elastic plate member suction port that is positioned outside the outer periphery of the holding surface and sucks in the underside of the inner periphery of the elastic plate member that protrudes above the holding surface, and the chuck table is capable of pulling the elastic plate member down to a position below the holding surface with the elastic plate member suction port.

[0010] In addition, in order to solve the above-mentioned problems, the present invention is a processing apparatus that suction-holds and processes a plate-shaped workpiece on the holding surface of the chuck table, the processing apparatus comprising a cleaning mechanism that cleans the holding surface, a holding surface suction path that connects the holding surface to a first suction source, and an elastic plate member suction path that connects the elastic plate member suction port to a second suction source, and the cleaning mechanism cleans the holding surface while the elastic plate member suction port sucks the underside of the elastic plate member and pulls the elastic plate member down to a position below the holding surface.

[0011] In addition, in order to solve the above-mentioned problems, the present invention is a method for machining a plate-shaped workpiece using the machining apparatus, comprising: a holding step in which the holding surface sucks and holds the plate-shaped workpiece by connecting the holding surface to the first suction source without connecting the elastic plate member suction port to the second suction source; a processing step in which the held plate-shaped workpiece is processed after the holding step; a separating step in which the processed plate-shaped workpiece is separated from the holding surface; an elastic plate member suction step in which the elastic plate member suction port is connected to the second suction source and the elastic plate member is sucked and held before the plate-shaped workpiece is separated from the holding surface; and a cleaning step in which the lower surface of the elastic plate member is sucked and held by the elastic plate member suction port after the plate-shaped workpiece has been separated from the holding surface, and the holding surface is cleaned in a state in which the elastic plate member is lowered to a position below the holding surface. Effect of the Invention

[0012] The chuck table of the present invention has a holding surface that suction-holds the underside of a plate-shaped workpiece whose outer periphery is warped higher than the central portion. The chuck table comprises: an elastic plate member that is plate-shaped and annular in plan view with an opening in the center; an elastic plate member gripping portion that aligns the center of the opening of the elastic plate member with the center of the holding surface, causing the outer periphery of the elastic plate member to protrude above the holding surface and gripping the inner periphery of the elastic plate member below the holding surface; and an annular elastic plate member suction port that is positioned outside the outer periphery of the holding surface and sucks in the underside of the outer periphery of the elastic plate member that protrudes above the holding surface. This makes it possible, when cleaning the holding surface, for the elastic plate member suction port to suck in the underside of the elastic plate member and pull the elastic plate member down to a position below the holding surface, making it possible to suction-hold a warped plate-shaped workpiece on the holding surface without vacuum leaks and to ensure that no machining debris remains on the holding surface after the holding surface has been cleaned.

[0013] The chuck table of the present invention has a holding surface that suction-holds the underside of a plate-shaped workpiece whose outer periphery is warped higher than the central portion. The chuck table comprises: an elastic plate member that is plate-shaped and annular in plan view with an opening in the center; an elastic plate member gripping portion that aligns the center of the opening of the elastic plate member with the center of the holding surface, causing the inner periphery of the elastic plate member to protrude above the holding surface and gripping the outer periphery of the elastic plate member below the holding surface; and an annular elastic plate member suction port that is positioned outside the outer periphery of the holding surface and sucks in the underside of the inner part of the elastic plate member that protrudes above the holding surface. This makes it possible, when cleaning the holding surface, for the elastic plate member suction port to suck in the underside of the elastic plate member and pull the elastic plate member down to a position below the holding surface, making it possible to suction-hold a warped plate-shaped workpiece on the holding surface without vacuum leaks and to ensure that no machining debris remains on the holding surface after the holding surface has been cleaned.

[0014] In addition, the processing apparatus of the present invention, which holds and processes a plate-shaped workpiece by suction on the holding surface of the chuck table, is equipped with a cleaning mechanism for cleaning the holding surface, a holding surface suction path connecting the holding surface to a first suction source, and an elastic plate member suction path connecting the elastic plate member suction port to a second suction source.This allows the cleaning mechanism to clean the holding surface while the elastic plate member suction port sucks the underside of the elastic plate member and pulls the elastic plate member down to a position below the holding surface, so that no processing debris remains on the holding surface after the holding surface has been cleaned.

[0015] In addition, the method for machining a plate-shaped workpiece according to the present invention using the machining device includes a holding step in which the holding surface sucks and holds the plate-shaped workpiece, without connecting the elastic plate member suction port to a second suction source, and the holding surface sucks and holds the plate-shaped workpiece; a processing step in which the held plate-shaped workpiece is machined after the holding step; a separation step in which the machined plate-shaped workpiece is separated from the holding surface; an elastic plate member suction step in which the elastic plate member suction port is connected to the second suction source and the elastic plate member is sucked and held before the plate-shaped workpiece is separated from the holding surface; and a cleaning step in which the elastic plate member suction port sucks and holds the lower surface of the elastic plate member, after the plate-shaped workpiece is separated from the holding surface, and the holding surface is cleaned in a state in which the elastic plate member is lowered to a position below the holding surface. This makes it possible to machine a warped plate-shaped workpiece by sucking and holding it on the holding surface without vacuum leaks, and also makes it possible to ensure that no machining debris remains on the holding surface after the holding surface is cleaned. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a perspective view showing an example of a grinding device. [Diagram 2] 2 is a cross-sectional view showing a conveying unit, a plate-shaped workpiece, and a chuck table of the first embodiment. FIG. [Diagram 3] FIG. 4 is a perspective view showing an example of a cleaning brush that constitutes a cleaning mechanism. [Figure 4] 4 is a cross-sectional view illustrating a state in which a plate-shaped workpiece is suction-held on the holding surface of the chuck table of the first embodiment in a holding step. FIG. [Diagram 5]10 is a cross-sectional view illustrating a state in which the holding surface of the chuck table of the first embodiment is being cleaned with a cleaning sponge in a cleaning step. FIG. [Figure 6] 4 is a cross-sectional view illustrating a state in which the holding surface of the chuck table of the first embodiment is being cleaned with a cleaning brush in a cleaning step. FIG. [Figure 7] FIG. 11 is a cross-sectional view showing a transport unit, a plate-shaped workpiece, and a chuck table of a second embodiment. [Figure 8] 13 is a partial cross-sectional view showing another example of an elastic plate member gripping portion and an elastic plate member in the chuck table of the second embodiment. FIG. [Figure 9] 10 is a cross-sectional view illustrating a state in which a plate-shaped workpiece is suction-held on the holding surface of the chuck table of the second embodiment in a holding step. FIG. [Figure 10] 10 is a cross-sectional view illustrating a state in which the holding surface of the chuck table of the second embodiment is being cleaned with a cleaning brush in a cleaning step. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The processing apparatus shown in FIG. 1 is a grinding apparatus 1 that uses a grinding unit 16 to grind a plate-shaped workpiece 9 held by suction on a chuck table 3 (hereinafter referred to as the chuck table 3 of embodiment 1), and the front (-Y direction side) on an equipment base 10 of the grinding apparatus 1 is an attachment / detachment area where the plate-shaped workpiece 9 is attached to and detached from the chuck table 3, and the rear (+Y direction side) on the equipment base 10 is a processing area where the grinding unit 16 grinds the plate-shaped workpiece 9 held on the chuck table 3. In addition, the processing device of the present invention is not limited to a processing device with a single-axis grinding unit 16 such as the grinding device 1, but may be a grinding device with two or more axes that has a rough grinding unit and a finish grinding unit and can position the plate-shaped workpiece 9 below the rough grinding unit or the finish grinding unit on a rotating turntable. In addition, the processing device according to the present invention may be a polishing device that polishes a plate-shaped workpiece 9 with a polishing pad, a cutting device that dices a plate-shaped workpiece 9 with a cutting blade, or a bit processing device that turns a plate-shaped workpiece 9 with a turning bit.

[0018] In the plate-shaped workpiece 9 shown in FIG. 1 and FIG. 2, IC chips are arranged at equal intervals in the central region of the upper surface of a rectangular substrate 90 made of, for example, a PCB, and the upper surface of the substrate 90 including the IC chips is molded with a resin 92 (for example, an epoxy resin). The plate-shaped workpiece 9, which is rectangular in plan view as a whole, has a warp in an outer peripheral portion 905 due to the contraction force of the molded resin 92. As shown in FIG. 2, the warp in the outer peripheral portion 905 of the plate-shaped workpiece 9 is, for example, a warp that gradually becomes higher from a central portion 904 of a lower surface 902 of the plate-shaped workpiece 9 that is held by suction toward the outer peripheral portion 905. The upper surface 920 of the resin 92 of the plate-shaped workpiece 9 becomes a grinding surface to be ground. The outer peripheral portion 905 protruding from the resin 92 becomes a scrap portion that will become mainly unnecessary later. The plate-shaped workpiece 9 is not limited to this example, and may be a silicon wafer or the like that is circular in plan view, or may be a workpiece in which an IC chip is not molded with the resin 92. In addition, a protective tape (not shown) may be attached to the lower surface 902 of the plate-shaped workpiece 9.

[0019] The chuck table 3 of the embodiment 1 shown in Fig. 1 and Fig. 2 includes a porous portion 34 having a holding surface 342 having an area, for example, smaller than the area of ​​the lower surface 902 of the plate-shaped workpiece 9. The holding surface 342, which is the upper surface of the porous portion 34, is formed, for example, in a rectangular shape in a plan view to match the rectangular plate-shaped workpiece 9. Note that the holding surface 342 may be formed in a circular shape in a plan view to match a circular plate-shaped workpiece.

[0020] 1, the chuck table 3 includes a table frame 31 that is, for example, circular in plan view, and the porous portion 34 is disposed so as to be fitted into a receiving portion 311 (shown in Fig. 2) that is rectangular in plan view and concave and formed on the upper surface of the table frame 31. For example, the porous portion 34 is adhesively fixed to the bottom surface of the receiving portion 311, and the upper surface of the table frame 31 and the holding surface 342 are flush with each other. Instead of the porous portion 34, the chuck table 3 may be provided with a suction portion having a suction groove formed on the upper surface.

[0021] 2, suction grooves 313 are formed in the bottom surface of the accommodation section 311 concentrically and radially about the center of the chuck table 3. Furthermore, an internal suction path 210 constituting the holding surface suction path 21 is formed from the suction groove 313 to the underside of the table frame 31 and further from the underside to a rotation shaft (not shown). As shown in FIG. 2, the internal suction path 210 is further connected to a first suction source 29 such as a vacuum generator through an external suction piping 214 constituting the holding surface suction path 21 via a rotary joint (not shown) or the like. For example, the suction piping 214 constituting the holding surface suction path 21 is provided with a holding surface suction valve 219 such as a solenoid valve that opens and closes the holding surface suction path 21 to switch between communication and non-communication between the first suction source 29 and the holding surface 342.

[0022] The chuck table 3 of the present invention comprises a plate sponge 35 which is annular in plan view and has an opening 350 in the center, an elastic plate member holding portion 36 (hereinafter referred to as the sponge holding portion 36 in this embodiment) which aligns the center of the opening 350 of the plate sponge 35 with the center of the holding surface 342, causes an outer peripheral portion 357 of the plate sponge 35 to protrude above the holding surface 342, and holds an inner peripheral portion 354 of the plate sponge 35 below the holding surface 342, and an annular elastic plate member suction port 32 (hereinafter referred to as the sponge suction port 32 in this embodiment) which sucks in the underside of the outer peripheral portion 357 of the plate sponge 35 which is positioned outside the outer periphery of the holding surface 342 and protrudes above the holding surface 342.

[0023] The sponge gripping portion 36 in the chuck table 3 of embodiment 1 shown in Figure 2 includes, for example, a clamp fitting groove 360 ​​formed around the accommodating portion 311 on the upper surface of the table frame 31, a sponge mounting groove 362 formed around the outer periphery of the clamp fitting groove 360, and a fixed clamp 364 having a rectangular ring shape when viewed in a plane.

[0024] The sponge mounting groove 362 shown in Figure 2 is formed, for example, by cutting out the top surface of the table frame 31 into a square ring shape when viewed in a plane, and the groove bottom is flat on the outer circumferential region and slopes downward toward the clamp fitting groove 360 ​​on the inner circumferential region.

[0025] 2 formed in a square ring shape in a plan view includes, for example, a ring cylinder portion 369 inserted into the clamp fitting groove 360, and a flange portion 368 extending substantially horizontally toward the outside of the chuck table 3 at the upper end side of the ring cylinder portion 369. The inner peripheral portion 354 of the plate sponge 35 placed in the sponge mounting groove 362 can be held from both above and below at a position below the holding surface 342 by the lower surface of the flange portion 368 and the inclined area of ​​the bottom of the sponge mounting groove 362. The plate sponge 35 placed and held in the inclined area of ​​the bottom of the sponge mounting groove 362 is inclined so as to become higher from the inside toward the outside, and a predetermined gap 366 is formed between the lower surface of the outer peripheral portion 357 of the plate sponge 35 protruding above the holding surface 302 and the flat area of ​​the bottom of the sponge mounting groove 362. 2 is fixed to the table frame 31 with bolts, and its flat upper surface is flush with, for example, the holding surface 342 and the upper surface of the table frame 31.

[0026] 1 and 2, which is an example of an elastic plate member formed in a rectangular ring shape in a plan view, is, for example, a single-cell sponge such as urethane foam or silicone sponge. It is also possible to use an open-cell sponge. The elastic plate member may also be a rubber plate. 2, the thickness of plate sponge 35 fixed by fixing clamp 364 while placed in sponge placement groove 362 shown in Fig. 2 is set so that in a natural state in which no external force is applied to plate sponge 35 from plate-shaped workpiece 9, outer peripheral portion 357 of plate sponge 35 is positioned higher than holding surface 342 of porous portion 34 and protrudes above holding surface 342. When outer peripheral portion 357 is applied with an external force in the -Z direction and deformed so as to be accommodated in gap 366, upper surface 351 of plate sponge 35 becomes flush with holding surface 342.

[0027] In this embodiment, the sponge suction port 32 opening into the flat area at the bottom of the sponge mounting groove 362 shown in Figure 2 is, for example, a plurality of circular holes formed at equal intervals in the X-axis direction and the Y-axis direction centered on the center of the holding surface 342 of the chuck table 3, but is not limited to this and may be a sponge suction port formed in the shape of a single square ring.

[0028] 2 to the underside of the table frame 31, and further from the underside to the rotating shaft (not shown), an internal suction path 240 constituting the elastic plate member suction path 24 (hereinafter referred to as the sponge suction path 24 in this embodiment) is formed. The internal suction path 240 is further connected to a second suction source 26 such as a vacuum generator through an external suction piping 244 constituting the sponge suction path 24 via a rotary joint (not shown) or the like. For example, the suction pipe 244 is provided with a sponge suction valve 247 such as a solenoid valve that opens and closes the sponge suction passage 24 to switch between communication and non-communication between the second suction source 26 and the sponge suction port 32 . In addition, the first suction source 29 and the second suction source 26 are a single suction source, and by opening and closing a valve, it may be possible to switch, for example, so that suction force is not transmitted to the sponge suction path 24 and is transmitted to the holding surface suction path 21.

[0029] 1, the chuck table 3 is surrounded by a cover 18 and can rotate about a rotation axis whose axial direction is the Z-axis direction (vertical direction), and can move back and forth in the Y-axis direction on the device base 10 by a Y-axis moving mechanism (not shown) disposed below the cover 18 and a bellows cover 180 connected to the cover 18 and extending and contracting in the Y-axis direction. The Y-axis moving mechanism (not shown) is an electric slider made of a ball screw or the like.

[0030] 1, a column 11 is erected in the machining area, and a grinding feed unit 17 is disposed on the front surface of the column 11 on the -Y direction side, which feeds the grinding unit 16 for grinding in the vertical direction (Z-axis direction) away from or toward the chuck table 3. The grinding feed unit 17 includes a ball screw 170 whose axial direction is the Z-axis direction, a pair of guide rails 171 disposed parallel to the ball screw 170, a lifting motor 172 connected to the upper end of the ball screw 170 for rotating the ball screw 170, and a lifting plate 173 whose internal nut is screwed into the ball screw 170 and whose side is in sliding contact with the guide rail 171. When the lifting motor 172 rotates the ball screw 170, the lifting plate 173 is guided by the guide rail 171 to reciprocate in the Z-axis direction, and the grinding unit 16 fixed to the lifting plate 173 is fed for grinding in the Z-axis direction.

[0031] The grinding unit 16, which grinds the plate-shaped workpiece 9 held on the chuck table 3, comprises a rotating shaft 160 whose axial direction is the Z-axis direction, a housing 161 that rotatably supports the rotating shaft 160, a motor 162 that rotates and drives the rotating shaft 160, a circular mount 163 connected to the lower end of the rotating shaft 160, a grinding wheel 164 that is removably attached to the lower surface of the mount 163, and a holder 165 that supports the housing 161 and is fixed to a lifting plate 173 of the grinding feed unit 17.

[0032] The grinding wheel 164 includes a wheel base 1641 and a plurality of grinding stones 1642, each having a substantially rectangular parallelepiped shape, arranged in a ring shape on the bottom surface of the wheel base 1641. The grinding stones 1642 are formed by, for example, fixing diamond abrasive grains or the like with a resin bond, a metal bond, or the like.

[0033] Inside the rotating shaft 160, a flow passage (not shown) that is connected to a grinding water supply source and serves as a passageway for grinding water is provided, penetrating in the axial direction (Z-axis direction) of the rotating shaft 160, and the flow passage (not shown) further passes through the mount 163 and opens at the bottom surface of the wheel base 1641 so that grinding water can be sprayed toward the grinding wheel 1642.

[0034] As shown in Figure 1, for example, a transport unit 4 is arranged at a position next to the movement path of the chuck table 3 in the attachment / detachment area on the device base 10, which transports a plate-shaped workpiece 9 onto the holding surface 342 of the chuck table 3 or transports the plate-shaped workpiece 9 from the holding surface 342.

[0035] The transport unit 4 includes a lifting mechanism 40 such as an electric cylinder or an air cylinder arranged on the device base 10, an arm portion 41 whose rear end is attached to the upper end side of a lifting rod (not shown) of the lifting mechanism 40 and extends horizontally above the movement path of the chuck table 3, and a holding pad 44 attached to the underside of the tip of the arm portion 41.

[0036] The holding pad 44 can be raised and lowered in the Z-axis direction by the lifting mechanism 40 and can be faced directly with the center of the holding surface 342 of the chuck table 3 in the Z-axis direction by aligning its center with that of the holding surface 342. Its underside serves as a suction surface 443 made of a porous material or the like, and a conveying suction source 449 such as a vacuum generator is connected to the suction surface 443 via a fitting, a plastic tube, or the like.

[0037] As shown in FIG. 1, the grinding apparatus 1 is provided with a cleaning mechanism 5 that cleans the holding surface 342 of the chuck table 3. The cleaning mechanism 5 is disposed, for example, via a lifting unit 54, on the front surface (-Y side surface) of a gate-type column 109 disposed on the apparatus base 10 so as to straddle the movement path of the chuck table 3 in the X-axis direction.

[0038] The lifting unit 54 is an electric cylinder (or a pneumatic cylinder) or the like attached to a gate-shaped column 109. The cleaning sponge 50 that constitutes the cleaning mechanism 5 shown in Figure 1 is, for example, a roll sponge made of a sponge of a predetermined thickness formed into a cylindrical shape, and extends in the X-axis direction for a length at least equal to or greater than the width of the holding surface 342 of the chuck table 3.

[0039] The cleaning sponge 50 may be, for example, a sponge made by foaming polyurethane, a PVA sponge, or a sponge made by kneading a foaming agent into rubber. The outer peripheral surface of the cleaning sponge 50 serves as a cleaning surface that comes into contact with and cleans the holding surface 342 of the chuck table 3.

[0040] The cleaning sponge 50 is rotatably supported by, for example, a support unit 56 that is raised and lowered by a lifting unit 54. The support unit 56 includes, for example, a shaft 560 that is inserted into the cylinder of the cleaning sponge 50 and has a plurality of water supply holes on its outer surface, and an arm 561 that rotatably supports the shaft 560.

[0041] The shaft 560 has a flow path formed therein, and the flow path communicates with each water supply hole. The shaft 560 housed in the approximately U-shaped portion of the arm 561 is supported by the arm 561, for example, via a bearing (not shown). One end of the flow path communicates with a cleaning water supply source (not shown) via a joint (not shown), a resin tube, or the like (not shown) attached to the side of the arm 561. The cleaning mechanism 5 is not limited to the form in which cleaning water is sprayed outward from the inside of the cleaning sponge 50 as described above, and may be provided with a cleaning nozzle near the cleaning sponge 50 that can spray cleaning water toward the contact portion between the cleaning sponge 50 and the holding surface 342 of the chuck table 3. The shaft 560 that rotatably supports the cleaning sponge 50 may be rotated by a motor (not shown).

[0042] The cleaning mechanism 5 may include a cleaning brush 57 shown in Fig. 3 instead of the cleaning sponge 50 shown in Fig. 1. The cleaning brush 57 is, for example, made of elastic resin fibers (e.g., nylon) formed into straight bristles and densely packed together, and the resin fibers are planted on the lower surface of a circular, plate-shaped brush plate 573. The upper surface of the brush plate 573 is connected to the lower end of the rod of the lifting unit 54 shown in Fig. 1. For example, one or more water outlets 578 are formed in the center of the brush plate 573 at locations that become gaps between the bristles, and the water outlet 578 is connected to a cleaning water supply source (not shown) via a resin tube, a joint, or the like.

[0043] For example, the cleaning brush 57 may be movable up and down in the Z-axis direction by the lifting unit 54 shown in Fig. 1 and rotated about a rotation axis whose axial direction is the Z-axis direction. In addition, the diameter of the cleaning brush 57 is, for example, at least larger than the length from the center of the holding surface 342 of the chuck table 3 shown in Fig. 1 to the outer periphery of the holding surface 342. For example, the cleaning mechanism 5 may be configured to perform stone cleaning using a cleaning whetstone instead of the cleaning brush 57. Also, two-fluid cleaning may be used in which two fluids, water and air, are sprayed.

[0044] 1, the operation of the grinding device 1 when grinding a plate-shaped workpiece 9 held on the chuck table 3 of the first embodiment will be described below. Also, each step of the machining method for the plate-shaped workpiece 9 using the grinding device 1 will be described.

[0045] (1) Holding process First, a holding process is performed in which the sponge suction port 32 shown in Figure 2 is not connected to the second suction source 26, but the holding surface 342 of the chuck table 3 is connected to the first suction source 29, and the holding surface 342 holds the plate-shaped workpiece 9 by suction. Specifically, first, as shown in FIG. 2, the plate-shaped workpiece 9 is brought into approximate alignment with the suction surface 443 of the holding pad 44 of the transport unit 4, and the upper surface 920 of the resin 92 is sucked and held by the suction surface 443. The upper surface 920 of the resin 92 may be sucked and held by the suction surface 443 in a state where the shape of the holding pad 44 and the shape of the plate-shaped workpiece 9 are substantially aligned.

[0046] 1 is moved in the Y-axis direction by a Y-axis movement mechanism (not shown) to be positioned, for example, directly below the holding pad 44 of the transport unit 4 in the attachment / detachment area. The chuck table 3 is also rotated by a predetermined angle so that the shape of the plate-shaped workpiece 9 suction-held by the holding pad 44 approximately matches the shape of the holding surface 342 of the chuck table 3. The suction force generated by the operation of the first suction source 29 shown in FIG. 2 is transmitted to the holding surface 342 of the chuck table 3 through the holding surface suction path 21.

[0047] 4, the holding pad 44 is lowered at a predetermined speed by the lifting mechanism 40. Then, the lower surface 902 of the plate-shaped workpiece 9, which is suction-held by the holding pad 44, comes into contact with the holding surface 342 of the chuck table 3. In addition, the outer peripheral portion 905 of the plate-shaped workpiece 9, which is provided with a warping element, comes into contact with the outer peripheral portion 357 protruding above the holding surface 342 of the plate sponge 35, so that the space formed by the lower surface 902 of the plate-shaped workpiece 9, the outer peripheral portion (protruding portion) 357 of the plate sponge 35, and the holding surface 342 of the chuck table 3 becomes a sealed space, and no vacuum leak occurs from the space.

[0048] Next, the holding surface suction valve 219 is opened, and the holding surface 342 is connected to the first suction source 29, whereby the space is connected to the first suction source 29, and the holding surface 342 suction-holds the plate-shaped workpiece 9. The upper end of the protruding outer peripheral portion 357 of the plate sponge 35 becomes flush with the holding surface 342, and the lower surface 902 of the plate-shaped workpiece 9 is suction-held over the entire holding surface 342, as shown in Fig. 4. The outer peripheral portion 357 of the plate sponge 35, which has been pressed downward and deformed by the outer peripheral portion 905 of the plate-shaped workpiece 9, enters the sponge placement groove 362 so as to fill the gap 366 (see Fig. 2), and the upper surface of the outer peripheral portion 357 becomes substantially flush with the upper surface of the fixed clamp 364, the upper surface of the table frame 31, and the holding surface 342. The portion of the substrate 90 that protrudes outward from the holding surface 342, which is the outer periphery 905 of the plate-shaped workpiece 9 (the portion not molded with resin 92), is an unnecessary scrap that will not become a product, but it is preferable that the annular plate sponge 35 is configured to contact just below the outer periphery of the resin 92 so as to follow the holding surface 342 and not come into contact with the grinding wheel 1642. The area of ​​the substrate 90 that becomes the product chip and is covered with resin 92 continues to be appropriately sucked and held by the holding surface 342.

[0049] As shown in FIG. 4, the plate-shaped workpiece 9 is in a state where the warp of the outer peripheral portion 905 is eliminated and the plate-shaped workpiece 9 is sucked and held by the chuck table 3 without any vacuum leakage, and the holding process is completed.

[0050] (2) Processing process After the holding pad 44 is released from the plate-shaped workpiece 9 held by suction on the chuck table 3, the chuck table 3 holding the plate-shaped workpiece 9 by suction is moved in the +Y direction from the attachment / detachment area to below the grinding unit 16 shown in Fig. 1 in the processing area by a Y-axis movement mechanism (not shown). Then, the center of rotation of the grinding wheel 1642 of the grinding unit 16 is shifted horizontally by a predetermined distance from the center of rotation of the plate-shaped workpiece 9, and the rotation trajectory of the grinding wheel 1642 is positioned so as to pass through the center of rotation of the plate-shaped workpiece 9.

[0051] 1 rotates the rotating shaft 160 at a predetermined rotation speed, and the grinding wheel 164 rotates accordingly. Then, the grinding unit 16 is sent in the -Z direction by the grinding feed unit 17, and the rotating grinding wheel 1642 comes into contact with the upper surface 920 of the resin 92 of the plate-shaped workpiece 9, thereby performing grinding. During grinding, the chuck table 3 rotates at a predetermined rotation speed, and the plate-shaped workpiece 9 held on the holding surface 342 also rotates, so that the grinding wheel 1642 grinds the entire upper surface 920 of the resin 92 of the plate-shaped workpiece 9. In addition, grinding water passing through a flow path (not shown) is supplied to the contact portion between the grinding wheel 1642 and the plate-shaped workpiece 9, and the contact portion is cooled and washed. Then, after the resin 92 of the plate-shaped workpiece 9 has been ground to a desired thickness, the grinding unit 16 is pulled upward by the grinding feed unit 17, and the grinding wheel 1642 is separated from the plate-shaped workpiece 9, completing the grinding. Furthermore, the warping of the outer peripheral portion 905 of the plate-shaped workpiece 9 is also eliminated by the grinding.

[0052] For example, when the above-described grinding process is performed successively on a plurality of plate-shaped workpieces 9 one by one, grinding debris and the like adheres to the holding surface 342 of the chuck table 3. In order to clean the holding surface 342, the sponge suction process to the cleaning process described below are performed at an appropriate timing, for example, after grinding of one plate-shaped workpiece 9 is completed and before grinding of the next new plate-shaped workpiece 9.

[0053] (3) Sponge suction process (elastic plate member suction process) When grinding of a plate-shaped workpiece 9 is completed, for example, the chuck table 3 which holds the plate-shaped workpiece 9 by suction after grinding is moved in the -Y direction by a Y-axis moving mechanism not shown, and is positioned directly below the holding pad 44 of the conveying unit 4 shown in Figure 1, before the plate-shaped workpiece 9 is separated from the holding surface 342, a sponge suction process is performed in which the sponge suction port 32 shown in Figure 5 is connected to the second suction source 26 to hold the plate sponge 35 by suction.

[0054] 5 is opened, and the suction force generated by the operation of the second suction source 26 is transmitted to the sponge suction port 32 through the sponge suction path 24. Then, the underside of the outer circumferential portion 357 of the plate sponge 35, which has entered the sponge placement groove 362 so as to fill the gap 366 due to the plate-shaped workpiece 9 being sucked and held on the holding surface 342, is sucked and held by the sponge suction port 32.

[0055] (4) Separation process The chuck table 3, which holds the plate-shaped workpiece 9 after grinding by suction, is moved in the -Y direction by a Y-axis moving mechanism (not shown) and positioned directly under the holding pad 44 of the transport unit 4 shown in Fig. 1. Then, for example, the suction force generated by the first suction source 29 shown in Fig. 5 is cut off from being transmitted to the holding surface 342 by closing the holding surface suction valve 219, and the plate-shaped workpiece 9 held by suction by the holding pad 44 is carried out from the holding surface 342. The outer peripheral portion 357 of the plate sponge 35 from which the plate-shaped workpiece 9 is separated is maintained in a state of being inserted into the sponge placement groove 362 so as to fill the gap 366 by the suction force transmitted to the sponge suction port 32, and the upper surface of the plate sponge 35 is maintained in a state of being lowered to a position below the holding surface 342 (in this embodiment, flush with the holding surface 342).

[0056] (5) Cleaning process After the plate-shaped workpiece 9 is separated from the holding surface 342 of the chuck table 3, the underside of the outer peripheral portion 357 of the plate sponge 35 is sucked and held by the sponge suction port 32, and the plate sponge 35 is lowered to a position below the holding surface 342, and a cleaning process is performed to clean the holding surface 342.

[0057] In the cleaning step, for example, a case where a cleaning sponge 50 shown in Figs. 1 and 5 is used will be described. For example, the chuck table 3 shown in FIG. 1 is sent in the +Y direction, and the lifting unit 54 lowers the arm 561 in the -Z direction to a predetermined height at which the lower part of the outer circumferential surface of the cleaning sponge 50 contacts the holding surface 342, as shown in FIG. 5. Also, cleaning water is supplied to the outer circumferential surface of the cleaning sponge 50 from inside the cleaning sponge 50, or cleaning water is sprayed / supplied from a cleaning nozzle (not shown) toward the contact part between the cleaning sponge 50 and the holding surface 342. Then, as the chuck table 3 moves in the +Y direction below the cleaning sponge 50 while the holding surface 342 is in contact with the cleaning sponge 50, the cleaning sponge 50 rotates due to the frictional force between the cleaning sponge 50 and the holding surface 342, and cleans the entire surface of the holding surface 342 together with the cleaning water. Alternatively, the shaft 560 shown in FIG. 1 rotates and the cleaning sponge 50 also rotates by a motor (not shown), and the cleaning sponge 50 cleans the entire surface of the holding surface 342.

[0058] In the holding step described above, the plate sponge 35, whose outer periphery 357 protruded above the holding surface 342 to complete the suction holding of the plate-shaped workpiece 9, has its outer periphery 357 pulled down to a position below the holding surface 342 in the cleaning step, so that the holding surface 342 is not surrounded by the plate sponge 35, and the cleaning water containing the grinding chips removed from the holding surface 342 flows down appropriately from above the holding surface 342, preventing the grinding chips from remaining on the holding surface 342. The cleaning water containing the grinding chips that flows down from the chuck table 3 flows into a water case inside the device base 10 from a drainage port (not shown) disposed on the side of the bellows cover 180 shown in FIG. Furthermore, the plate sponge 35 is not damaged by the cleaning sponge 50.

[0059] The holding surface 342 is cleaned with the cleaning sponge 50 and cleaning water, and the cleaning of the holding surface 342 with the cleaning sponge 50 is completed, for example, by moving the chuck table 3 in the +Y direction until it has completely passed under the cleaning sponge 50. Note that the holding surface 342 may be further cleaned with the cleaning sponge 50 by moving the chuck table 3 back and forth in the Y-axis direction.

[0060] In the cleaning step, for example, a case where a cleaning brush 57 shown in Figs. 3 and 6 is used will be described. For example, the chuck table 3 after the sponge suction process is sent in the Y-axis direction, and the chuck table 3 and the cleaning brush 57 are aligned so that the cleaning brush 57 covers the area from the center of the chuck table 3 to one side edge of the table frame 31, as shown in Figure 6, and then the chuck table 3 stops moving in the Y-axis direction directly below the cleaning brush 57.

[0061] 1 lowers the cleaning brush 57 to a predetermined height at which the cleaning brush 57 comes into contact with the holding surface 342. Also, cleaning water is supplied from inside the cleaning brush 57 to the contact portion with the holding surface 342, or cleaning water is sprayed / supplied from a cleaning nozzle (not shown) toward the contact portion between the cleaning brush 57 and the holding surface 342. Then, while the cleaning brush 57 is in contact with the holding surface 342, the chuck table 3 rotates at a predetermined rotational speed, and the cleaning brush 57 also rotates at a predetermined rotational speed, so that the cleaning brush 57 cleans the entire surface of the holding surface 342 together with the cleaning water.

[0062] In the cleaning process, because outer peripheral portion 357 of plate sponge 35 is pulled down to a position below holding surface 342, holding surface 342 is not surrounded by plate sponge 35, and cleaning water containing grinding debris removed from holding surface 342 flows down appropriately from above holding surface 342, preventing grinding debris from remaining on holding surface 342. Then, holding surface 342 is cleaned with cleaning brush 57 and cleaning water for a predetermined time, and cleaning of holding surface 342 by cleaning brush 57 is completed.

[0063] As described above, the chuck table 3 according to the first embodiment of the present invention has a holding surface 342 for suction-holding the underside 902 of the plate-shaped workpiece 9 whose outer periphery is warped upward from the central portion 904. The chuck table 3 includes a plate sponge 35 (elastic plate member 35) which is annular in plan view and has an opening 350 in the center, a sponge gripping portion 36 (elastic plate member gripping portion 36) which aligns the center of the opening 350 of the plate sponge 35 with the center of the holding surface 342, causes an outer periphery portion 357 of the plate sponge 35 to protrude above the holding surface 342, and grips an inner periphery portion 354 of the plate sponge 35 below the holding surface 342, and and an annular sponge suction port 32 (elastic plate member suction port 32) which sucks the underside of the outer circumferential portion 357 of the plate sponge 35 which is disposed outside the outer periphery of 42 and protrudes above the holding surface 342. This makes it possible for the sponge suction port 32 to suck the underside of the plate sponge 35 and pull the plate sponge 35 down to a position below the holding surface 342, thereby enabling the warped plate-shaped workpiece 9 to be sucked and held on the holding surface 342 without vacuum leaks while being ground, and also making it possible to ensure that no machining debris remains on the holding surface 342 after the holding surface 342 has been washed.

[0064] In addition, the grinding device 1 according to the present invention, which holds the plate-shaped workpiece 9 by suction on the holding surface 342 of the chuck table 3 and processes it, is equipped with a cleaning mechanism 5 for cleaning the holding surface 342, a holding surface suction path 21 that connects the holding surface 342 to the first suction source 29, and a sponge suction path 24 that connects the sponge suction port 32 to the second suction source 26, so that the cleaning mechanism 5 can clean the holding surface 342 while the sponge suction port 32 sucks the underside of the outer circumferential portion 357 of the plate sponge 35 and pulls the plate sponge 35 down to a position below the holding surface 342, so that after cleaning the holding surface 342, no machining debris remains on the holding surface 342. In addition, the cleaning mechanism 5 does not damage the plate sponge 35.

[0065] Furthermore, the method for machining a plate-shaped workpiece 9 according to the present invention using the grinding device 1 includes a holding step in which the holding surface 342 is connected to the first suction source 29 without connecting the sponge suction port 32 to the second suction source 26 and the holding surface 342 suction-holds the plate-shaped workpiece 9, a processing step in which the plate-shaped workpiece 9 held by suction on the chuck table 3 after the holding step is machined, a separation step in which the machined plate-shaped workpiece 9 is separated from the holding surface 342, and a step in which the sponge suction port 32 is connected to the second suction source 26 and the plate sponge 3 is removed before the plate-shaped workpiece 9 is separated from the holding surface 342. The method includes a sponge suction step of suctioning and holding plate sponge 35 by suction, and a cleaning step of, after separating plate-shaped workpiece 9 from holding surface 342, suctioning and holding the underside of outer circumferential portion 357 of plate sponge 35 by sponge suction port 32, and cleaning holding surface 342 in a state where plate sponge 35 is lowered to a position below holding surface 342, thereby making it possible to perform machining by suctioning and holding warped plate-shaped workpiece 9 on holding surface 342 without vacuum leak, and also to make it possible to make holding surface 342 free of machining debris after cleaning. Furthermore, plate sponge 35 is not damaged by, for example, cleaning brush 57 or cleaning sponge 50 during cleaning of holding surface 342.

[0066] The chuck table and grinding device according to the present invention are not limited to the above-mentioned embodiment, and may be embodied in various different forms within the scope of the technical concept. Also, each step in the method for machining a plate-shaped workpiece according to the present invention may be appropriately modified within the scope of the effect of the present invention.

[0067] For example, the grinding apparatus 1 shown in Fig. 1 may include a chuck table 39 shown in Fig. 7 instead of the chuck table 3 of the first embodiment. The chuck table 39 will be referred to as the chuck table of the second embodiment below. The chuck table 39 comprises a plate sponge 35 which is annular in plan view and has an opening 350 in the center, an elastic plate member holding portion 33 (hereinafter referred to as the sponge holding portion 33 in this embodiment) which aligns the center of the opening 350 of the plate sponge 35 with the center of the holding surface 342, causes an inner peripheral portion 354 of the plate sponge 35 to protrude above the holding surface 342, and holds an outer peripheral portion 357 of the plate sponge 35 below the holding surface 342, and an annular elastic plate member suction port 32 (hereinafter referred to as the sponge suction port 32 in this embodiment) which sucks in the underside of the inner peripheral portion 354 of the plate sponge 35 which is positioned outside the outer periphery of the holding surface 342 and protrudes above the holding surface 342.

[0068] Below, we will explain the sponge gripping portion 33, which is a difference between the chuck table 39 of embodiment 2 and the chuck table 3 of embodiment 1 shown in Figure 2, and similar parts will be given the same numbers and their explanations will be omitted.

[0069] The sponge holding portion 33 includes, for example, a sponge mounting groove 332 formed near the periphery of the storage portion 311 on the upper surface of the table frame 31, a clamp fitting groove 335 formed on the outer periphery of the sponge mounting groove 332, and a fixed clamp 338 having a rectangular ring shape when viewed in a plane.

[0070] The sponge mounting groove 332 is formed, for example, by cutting out the top surface of the table frame 31 in a square ring shape when viewed from above, and the inner circumferential region of the groove bottom is flat, and the outer circumferential region is inclined so as to become lower toward the clamp fitting groove 335 located on the outside. The sponge suction port 32 described above opens in the flat region on the inner circumferential side of the groove bottom of the sponge mounting groove 332.

[0071] The fixed clamp 338 formed in a square ring shape in a plan view includes, for example, a ring cylinder portion 339 inserted into the clamp fitting groove 335, and a flange portion 337 extending substantially horizontally from the upper end side of the ring cylinder portion 339 toward the center side of the chuck table 39. The lower surface of the flange portion 337 and the inclined area of ​​the bottom of the sponge mounting groove 332 allow the outer peripheral portion 357 of the plate sponge 35 placed in the sponge mounting groove 332 to be gripped from both above and below at a position below the holding surface 342. The plate sponge 35 placed in the inclined area of ​​the bottom of the sponge mounting groove 332 is inclined so as to become lower from the inside to the outside, and a predetermined gap 334 is formed between the lower surface of the inner peripheral portion 354 protruding above the holding surface 302 and the flat area of ​​the bottom of the sponge mounting groove 332. Furthermore, the fixed clamp 338 is fixed to the table frame 31 with bolts, and its flat upper surface is flush with the holding surface 342, for example.

[0072] In the chuck table 39 of the second embodiment, the sponge gripping portion 33 is not limited to the example shown in FIG. For example, sponge placement groove 375 constituting sponge gripping portion 37 of another example shown in Fig. 8 has a deepest area on the inner periphery side of its bottom, and sponge suction port 32 opens into this deepest area. Sponge suction port 32 is connected to sponge suction path 24. The area located next to the deepest area of ​​the bottom is groove bottom protrusion 3755 that protrudes upward in a one-step square ring convex shape so as to be the highest area at the groove bottom, and the area further to the outer periphery of groove bottom protrusion 3755 at the groove bottom is a flat surface that is one step lower than groove bottom protrusion 3755.

[0073] As shown in FIG. 8, in the plate sponge 35 placed in the sponge placement groove 375 and held by the fixed clamp 338, in a natural state in which no external force is applied to the plate sponge 35 from the plate-shaped workpiece 9, the inner peripheral portion 354 of the plate sponge 35 is located higher than the holding surface 342 (see FIG. 7) of the porous portion 34 and protrudes above the holding surface 342. A predetermined gap is formed between the lower surface of the inner peripheral portion 354 protruding above the holding surface 302 and the deepest area of ​​the bottom of the sponge placement groove 375. Furthermore, a push-out gap 3758 is formed between the ridge portion (corner portion) between the groove bottom protruding portion 3755 of the sponge placement groove 375 and the area on the outer periphery side of the groove bottom protruding portion 3755, and the lower surface of the plate sponge 35. The push-out gap 3758 is a gap for making it easier to push out contaminants such as machining chips to the sponge suction port 32 side.

[0074] The operation of the grinding device 1 shown in Fig. 1 when grinding a plate-shaped workpiece 9 held on the chuck table 39 of the second embodiment shown in Fig. 7 will be described below. Also, each step of the method for machining the plate-shaped workpiece 9 using the grinding device 1 will be described.

[0075] (1) Holding process First, the plate-shaped workpiece 9 shown in FIG. 1 is held by suction on the upper surface 920 of the resin 92 by the suction surface 443 with the shape of the holding pad 44 and the shape of the plate-shaped workpiece 9 roughly matching and their centers aligned. 7, the chuck table 39 is positioned directly below the holding pad 44. The chuck table 39 is rotated by a predetermined angle so that the shape of the plate-shaped workpiece 9 sucked and held by the holding pad 44 approximately matches the shape of the holding surface 342 of the chuck table 39. Furthermore, the suction force generated by the first suction source 29 is transmitted to the holding surface 342 of the chuck table 39 through the holding surface suction path 21.

[0076] 9, the central portion 904 of the lower surface 902 of the plate-shaped workpiece 9, which is sucked and held by the descending holding pad 44, comes into contact with the holding surface 342 of the chuck table 39. In addition, the outer peripheral portion 905 of the lower surface 902 of the plate-shaped workpiece 9, which is sucked and held by the descending holding pad 44, comes into contact with the inner peripheral portion 354 protruding above the holding surface 342 of the plate sponge 35, so that the space formed by the lower surface 902 of the plate-shaped workpiece 9, the inner peripheral portion 354 of the plate sponge 35, and the holding surface 342 of the chuck table 39 becomes a sealed space, and there is no vacuum leak from the space. Next, the holding surface suction valve 219 is opened to connect the holding surface 342 to the first suction source 29, so that the space is connected to the first suction source 29, and the holding surface 342 sucks and holds the plate-shaped workpiece 9. In addition, the upper end of the protruding inner peripheral portion 354 of plate sponge 35 becomes flush with holding surface 342, and the underside 902 of plate-shaped workpiece 9 is sucked and held by the entire holding surface 342, as shown in Fig. 9. In addition, inner peripheral portion 354 of plate sponge 35, which has been pressed downward and deformed by outer peripheral portion 905 of plate-shaped workpiece 9, enters sponge mounting groove 332 so as to fill gap 334 (see Fig. 7), and the upper surface of inner peripheral portion 354 becomes approximately flush with holding surface 342. The outer peripheral portion 905 of the plate-shaped workpiece 9, which is a portion protruding from the holding surface 342 of the substrate 90 (a portion not molded with the resin 92), becomes an unnecessary scrap portion that does not become a product, but it is preferable that the annular plate sponge 35 is configured to be in contact with just below the outer periphery of the resin 92 so as to follow the holding surface 342 and not to come into contact with the grinding wheel 1642. The area of ​​the substrate 90 that becomes the product chip and is covered with the resin 92 continues to be appropriately sucked and held by the holding surface 342.

[0077] (2) Processing process 9, after the plate-shaped workpiece 9 is sucked and held by the chuck table 39 without any vacuum leaks with the warpage of the outer peripheral portion 905 eliminated, the chuck table 39 holding the plate-shaped workpiece 9 by suction is moved in the +Y direction from the attachment / detachment area to below the grinding unit 16 shown in Fig. 1 in the processing area by a Y-axis movement mechanism (not shown). Since the processing of the plate-shaped workpiece 9 in the processing step is the same as when the chuck table 3 in the first embodiment is used, the following description will be omitted.

[0078] (3) Sponge suction process (elastic plate member suction process) When the grinding of the plate-shaped workpiece 9 is completed, for example, the chuck table 39 that holds the plate-shaped workpiece 9 by suction after grinding moves in the -Y direction and is positioned directly under the holding pad 44 of the transport unit 4 shown in FIG. 1 before the plate-shaped workpiece 9 is separated from the holding surface 342, a sponge suction process is performed in which the sponge suction port 32 shown in FIG. 10 is connected to the second suction source 26 to hold the plate sponge 35 by suction. That is, the sponge suction valve 247 shown in FIG. 10 is opened, and the suction force generated by the second suction source 26 is transmitted to the sponge suction port 32 through the sponge suction path 24. Then, the lower surface of the inner peripheral portion 354 that has entered the sponge placement groove 332 of the plate sponge 35 so as to fill the gap 334 (see FIG. 7) by the plate-shaped workpiece 9 that is held by suction on the holding surface 342 is held by the sponge suction port 32 by suction.

[0079] (4) Separation process The separating step of separating the machined plate-shaped workpiece 9 from the holding surface 342 of the chuck table 39 is also similar to the case where the chuck table 3 of the first embodiment is used, and therefore the following description will be omitted. After the transmission of suction force from the first suction source 29 to the holding surface 342 is cut off and the plate-shaped workpiece 9 held by suction by the holding pad 44 is transported away from the holding surface 342, the inner peripheral portion 354 of the plate sponge 35 from which the plate-shaped workpiece 9 has separated is maintained in a state in which it has penetrated into the sponge mounting groove 332 so as to fill the gap 334 by the suction force transmitted to the sponge suction port 32, and the upper surface of the plate sponge 35 is maintained in a state in which it is pulled down to a position below the holding surface 342 (in this embodiment, flush with the holding surface 342).

[0080] (5) Cleaning process In the cleaning step performed next, for example, a case where a cleaning brush 57 shown in Figures 3 and 10 is used will be described. Note that the holding surface 342 of the chuck table 39 may be cleaned using the cleaning sponge 50 shown in Figure 1. For example, the chuck table 39 is moved in the +Y direction to be positioned below the cleaning brush 57, and as shown in Fig. 10, the lifting unit 54 (see Fig. 1) lowers the cleaning brush 57 to a predetermined height where it comes into contact with the holding surface 342. Also, cleaning water is supplied from inside the cleaning brush 57 to the contact portion with the holding surface 342, or cleaning water is sprayed / supplied from a cleaning nozzle (not shown) toward the contact portion between the cleaning brush 57 and the holding surface 342. Then, while the holding surface 342 is in contact with the rotating cleaning brush 57, the chuck table 39 rotates at a predetermined rotation speed, whereby the cleaning brush 57 cleans the entire surface of the holding surface 342 together with the cleaning water.

[0081] In the cleaning process, since plate sponge 35 is lowered to a position below holding surface 342, holding surface 342 is not surrounded by plate sponge 35, and cleaning water containing grinding debris removed from holding surface 342 flows down appropriately from above holding surface 342, preventing grinding debris from remaining on holding surface 342. Then, holding surface 342 is cleaned with cleaning brush 57 and cleaning water for a predetermined time, and cleaning of holding surface 342 by cleaning brush 57 is completed.

[0082] As described above, the chuck table 39 of the second embodiment according to the present invention has a holding surface 342 for suction-holding the underside of the plate-shaped workpiece 9 whose outer periphery is warped upward from the central portion 904. The chuck table 39 includes a plate sponge 35 (elastic plate member 35) which is annular in plan view and has an opening 350 in the center, a sponge gripping portion 33 (elastic plate member gripping portion 33) which aligns the center of the opening 350 of the plate sponge 35 with the center of the holding surface 342, causes an inner peripheral portion 354 of the plate sponge 35 to protrude above the holding surface 342, and grips an outer peripheral portion 357 of the plate sponge 35 below the holding surface 342, and By providing an annular sponge suction port 32 (elastic plate member suction port 32) that sucks the underside of the inner peripheral portion 354 of the plate sponge 35 that is positioned outside the outer periphery and protrudes above the holding surface 342, the sponge suction port 32 can suck the underside of the inner peripheral portion 354 of the plate sponge 35 and pull the plate sponge 35 down to a position below the holding surface 342, making it possible to suck and hold the warped plate-shaped workpiece 9 on the holding surface 342 without vacuum leaks and to ensure that no machining debris remains on the holding surface 342 after the holding surface 342 is cleaned. In addition, the plate sponge 35 may be sucked through the sponge suction port 32, the holding surface 342 may be cleaned, and then the sponge suction port 32 may be opened to the atmosphere, causing, for example, the inner peripheral portion 354 of the plate sponge 35 to pop out from the holding surface 342, and then the sponge suction port 32 may be connected to the second suction source 26, and water containing machining debris that has entered the sponge mounting groove 362 may be discharged from the sponge mounting groove 362. [Explanation of symbols]

[0083] 9: Plate-shaped workpiece 9: Substrate 92: Resin 920: Top surface of resin (top surface of plate-shaped workpiece) 902: Bottom surface of plate-shaped workpiece 905: Outer periphery 1: Grinding device (processing device) 10: Device base 11: Column 16: Grinding unit 164: Grinding wheel 17: Grinding feed unit 170: Ball screw 172: Lifting motor 3: Chuck table of embodiment 1 34: Porous portion 342: Support surface 31: Table frame 311: Storage section 313: Suction groove 35: Plate sponge (elastic plate member) 350: Opening of plate sponge 351: Upper surface of plate sponge 354: Lower surface of plate sponge 36: Sponge gripping portion (elastic plate member gripping portion) 360: Clamp fitting groove 362: Sponge placement groove 364: Fixed clamp 32: Sponge suction port (elastic plate member suction port) 18: Cover 180: Bellows cover 21: Holding surface suction passage 210: Internal suction passage 214: Suction piping 219: Holding surface suction valve 29: 1st suction source 24: Sponge suction passage (elastic plate member suction passage) 240: Internal suction passage 244: Suction piping 247: Sponge suction valve 26: Second suction source 4: Transport unit 40: Lifting mechanism 41: Arm section 44: Holding pad 443: Suction surface 449: Transport suction source 109: Gate-shaped column 5: Cleaning mechanism 54: Lifting unit 50: Cleaning sponge 56: Support unit 560: Shaft 561: Arm 57: Cleaning brush 573: Brush plate 578: Water nozzle 39: Chuck table of embodiment 2 33: Sponge gripping portion (elastic plate member gripping portion) 37: sponge gripping portion 375: sponge placement groove 3755: groove bottom protrusion

Claims

1. A chuck table having a holding surface that suction-holds a bottom surface of a plate-shaped workpiece having an outer periphery warped higher than a central portion, the elastic plate member has a plate-like shape and is annular in plan view with an opening in the center; an elastic plate member gripping portion that aligns the center of the opening of the elastic plate member with the center of the holding surface, causes an outer circumferential portion of the elastic plate member to protrude above the holding surface, and grips an inner circumferential portion of the elastic plate member below the holding surface; and an annular elastic plate member suction port that is disposed outside the outer periphery of the holding surface and sucks in the underside of the outer circumferential portion of the elastic plate member that protrudes above the holding surface, The chuck table has an elastic plate member suction port that sucks the lower surface of the elastic plate member, thereby pulling the elastic plate member down to a position below the holding surface.

2. A chuck table having a holding surface that suction-holds a bottom surface of a plate-shaped workpiece having an outer periphery warped higher than a central portion, the elastic plate member has a plate-like shape and is annular in plan view with an opening in the center; an elastic plate member gripping portion that aligns the center of the opening of the elastic plate member with the center of the holding surface, causes an inner peripheral portion of the elastic plate member to protrude above the holding surface, and grips an outer peripheral portion of the elastic plate member below the holding surface; and an annular elastic plate member suction port that is disposed outside the outer periphery of the holding surface and sucks in the underside of the inner peripheral portion of the elastic plate member that protrudes above the holding surface, The chuck table has an elastic plate member suction port that sucks the lower surface of the elastic plate member, thereby pulling the elastic plate member down to a position below the holding surface.

3. A processing apparatus for processing a plate-shaped workpiece by suction holding the plate-shaped workpiece on the holding surface of the chuck table according to claim 1 or 2, a cleaning mechanism for cleaning the holding surface, a holding surface suction path for connecting the holding surface to a first suction source, and an elastic plate member suction path for connecting the elastic plate member suction port to a second suction source, The elastic plate suction port sucks the lower surface of the elastic plate to pull the elastic plate down to a position below the holding surface, and the cleaning mechanism cleans the holding surface.

4. A method for machining a plate-shaped workpiece using the machining apparatus according to claim 3, a holding step in which the elastic plate member suction port is not connected to the second suction source, and the holding surface is connected to the first suction source, and the holding surface suction-holds the plate-shaped workpiece; After the holding step, a processing step of processing the held plate-shaped workpiece; a separating step of separating the processed plate-shaped workpiece from the holding surface; an elastic plate member suction step of connecting the elastic plate member suction port to the second suction source to suction and hold the elastic plate member before separating the plate-shaped workpiece from the holding surface; and a cleaning step of, after separating the plate-shaped workpiece from the holding surface, suction-holding the lower surface of the elastic plate member with the elastic plate member suction port, and cleaning the holding surface while the elastic plate member is lowered to a position below the holding surface.

Images