Processing method of workpiece

Abstract

To provide a method for processing a workpiece that can provide high flatness of a surface to be polished while efficiently processing a workpiece.SOLUTION: A method for processing a workpiece which is applied when processing a plate-like workpiece having a first surface and a second surface located on an opposite side to the first surface includes: a grinding step of grinding a workpiece from a second surface side with a grinding wheel; a washing step of washing a surface to be ground of the workpiece after the grinding step; and a polishing step for polishing the workpiece from the side of the surface to be ground with a polishing pad after the washing step.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method for processing a workpiece, which is applied when processing a plate-shaped workpiece such as a wafer. [Background technology]

[0002] In order to realize small and lightweight device chips, there are increasing opportunities to thin wafers on which devices such as integrated circuits are mounted on the front side. For example, the front side of the wafer is held by a chuck table, and the chuck table and a grinding wheel with a grinding stone containing abrasive grains fixed thereto are rotated relative to each other, and the grinding stone is pressed against the back side of the wafer while supplying a liquid such as pure water, thereby grinding the wafer to thin it.

[0003] On the other hand, when a wafer is ground with the above-mentioned grinding wheel (grinding stone), damaged areas including scratches and distortions are formed on the ground surface, which tends to result in a lack of mechanical strength (such as transverse strength) of the wafer. Therefore, after the wafer is ground, the ground surface of the wafer is polished with a polishing pad, for example, to remove the damaged areas. In recent years, a composite processing device has been proposed that is structured to perform grinding and polishing continuously so that such processing can be carried out efficiently (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-153090 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned composite processing apparatus, the chuck table moves from a grinding area where a grinding wheel is placed to a polishing area where a polishing pad is placed, thereby continuously grinding and polishing the wafer. However, after grinding, small amounts of debris generated during grinding may remain on the wafer and chuck table. If the wafer is polished in this state, the wafer will be scraped by the debris, resulting in a decrease in the flatness of the polished surface.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a method for processing a workpiece that can efficiently process the workpiece while achieving high flatness of the polished surface. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a method for processing a workpiece that is applied when processing a plate-shaped workpiece having a first surface and a second surface opposite to the first surface, the method including: a grinding step of grinding the workpiece from the second surface side with a grinding wheel; a cleaning step of cleaning the surface to be ground of the workpiece after the grinding step; and a polishing step of polishing the workpiece from the surface to be ground with a polishing pad after the cleaning step. In the cleaning step, a cleaning fluid is supplied from the cleaning nozzle while the cleaning nozzle is moved together with the polishing pad. A method for processing a workpiece is provided.

[0008] According to another aspect of the present invention, there is provided a method for machining a plate-shaped workpiece having a first surface and a second surface opposite to the first surface, the method including: a holding step of holding the first surface side of the workpiece on a chuck table; a grinding step of grinding the workpiece held on the chuck table from the second surface side with a grinding wheel after the holding step; a cleaning step of cleaning the surface to be ground of the workpiece held on the chuck table together with the chuck table after the grinding step; and a polishing step of polishing the workpiece held on the chuck table from the surface to be ground with a polishing pad after the cleaning step. In the cleaning step, a cleaning fluid is supplied from the cleaning nozzle while the cleaning nozzle is moved together with the polishing pad. A method for processing a workpiece is provided. [Effects of the Invention]

[0010] In a method for processing a workpiece according to one aspect of the present invention, the workpiece is ground with a grinding wheel, the grinding surface of the workpiece is cleaned, and then the workpiece is polished with a polishing pad.Therefore, when the workpiece is polished with the polishing pad, debris generated during grinding has been sufficiently removed from the grinding surface.

[0011] Therefore, even when grinding and polishing are performed successively, a highly flat surface can be achieved. That is, according to the method for processing a workpiece according to one aspect of the present invention, a highly flat surface can be achieved while efficiently processing the workpiece.

[0012] Similarly, in a method for processing a workpiece according to another aspect of the present invention, after the workpiece is ground with a grinding wheel, the grinding surface of the workpiece is cleaned together with the chuck table, and then the workpiece is polished with a polishing pad.Therefore, when the workpiece is polished with the polishing pad, any debris generated during grinding has been sufficiently removed from the grinding surface and the chuck table.

[0013] Therefore, even when grinding and polishing are performed successively, it is possible to prevent debris from getting caught between the polishing pad and the workpiece, and to achieve a high level of flatness on the polished surface. That is, according to the method for processing a workpiece according to another aspect of the present invention, it is possible to efficiently process the workpiece while achieving a high level of flatness on the polished surface. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view schematically showing how a protective member is attached to a disk-shaped workpiece. [Figure 2] FIG. 2 is a cross-sectional view schematically showing a state in which a workpiece is held on a chuck table via a protective member. [Figure 3] FIG. 3 is a cross-sectional view that schematically shows how a workpiece held on a chuck table is ground by a grinding wheel. [Figure 4] FIG. 4 is a cross-sectional view that schematically shows how the grinding surface of the workpiece and the chuck table are cleaned. [Figure 5] FIG. 5 is a cross-sectional view that schematically shows how a workpiece held on a chuck table is polished by a polishing pad. [Figure 6] FIG. 6 is a front view schematically showing a polishing unit moving mechanism which is also used as a nozzle swinging mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the method for processing a workpiece according to this embodiment, first, a protective member is attached to a disk-shaped workpiece to be processed (attaching step). Fig. 1 is a perspective view schematically showing how a protective member 21 is attached to a disk-shaped workpiece 11.

[0016] The workpiece 11 is, for example, a disk-shaped wafer made of a semiconductor such as silicon (Si). That is, the workpiece 11 has a circular front surface (first surface) 11a and a circular back surface (second surface) 11b opposite the front surface 11a. The front surface 11a side of the workpiece 11 is divided into a plurality of small regions by a plurality of intersecting streets (planned division lines) 13, and a device 15 such as an integrated circuit (IC) is formed in each small region.

[0017] In the method for processing a workpiece according to this embodiment, the workpiece 11 is processed from the back surface 11b side so as to thin the entire workpiece 11. More specifically, in the method for processing a workpiece according to this embodiment, the workpiece 11 is ground from the back surface 11b side with a grinding wheel, and then polished with a polishing pad.

[0018] In this embodiment, a disk-shaped wafer made of a semiconductor such as silicon is used as the workpiece 11, but the material, shape, structure, size, etc. of the workpiece 11 are not limited to this embodiment. For example, a substrate made of other semiconductors, ceramics, resin, metal, etc. may be used as the workpiece 11. Similarly, the type, number, shape, structure, size, arrangement, etc. of the devices 15 are not limited to the above embodiment. The devices 15 do not have to be formed on the workpiece 11.

[0019] The protective member 21 attached to the workpiece 11 is typically a circular resin tape (resin film) having approximately the same diameter as the workpiece 11, a resin substrate, a wafer of the same or different type as the workpiece 11, or the like. For example, an adhesive layer exhibiting adhesive strength to the workpiece 11 is provided on the surface 21a side of this protective member 21. Therefore, as shown in FIG. 1 , the protective member 21 is attached to the surface 11a of the workpiece 11 by bringing the surface 21a side of the protective member 21 into close contact with the surface 11a of the workpiece 11.

[0020] As a result, the protective member 21 absorbs the impact applied when the workpiece 11 is processed from the back surface 11b side, and the device 15 on the front surface 11a side is protected. Note that if the protective member 21 can be fixed by adhering it to the workpiece 11 without an adhesive layer, the protective member 21 does not need to have an adhesive layer. Also, if the impact applied to the front surface 11a side when the workpiece 11 is processed is not a problem, the protective member 21 does not necessarily need to be attached to the workpiece 11.

[0021] After the protective member 21 is attached to the surface 11a of the workpiece 11, the surface 11a side of the workpiece 11 is held on a chuck table via the protective member 21 (holding step). Fig. 2 is a cross-sectional view that schematically shows how the workpiece 11 is held on the chuck table 4 of the processing device 2 via the protective member 21. Note that the composite processing device 2 shown in Fig. 2 and other figures is used in each of the following steps.

[0022] The processing device 2 is equipped with a chuck table 4 configured to be able to hold a workpiece 11. The chuck table 4 includes a disk-shaped frame 6 made of, for example, ceramics or the like. A recess 6a having a circular opening at the top end is formed on the upper surface of the frame 6, and a porous disk-shaped holding plate 8 made of, for example, ceramics or the like is fixed to the recess 6a.

[0023] The upper surface 8a of the holding plate 8 is configured in a shape corresponding to the side surface of a cone, for example, and functions as a holding surface for holding the workpiece 11, etc. The difference in height (height difference) between the center 8b of the upper surface 8a of the holding plate 8, which corresponds to the apex of the cone, and the outer periphery of the upper surface 8a of the holding plate 8 is approximately 10 μm to 30 μm. In this embodiment, the back surface 21b of the protective member 21 comes into contact with the upper surface (holding surface) 8a of the holding plate 8.

[0024] The lower surface side of the holding plate 8 is connected to a suction source (not shown) such as an ejector via a flow path 6b provided inside the frame 6 and a valve (not shown) arranged outside the frame 6. Therefore, when the valve is opened and negative pressure from the suction source is applied with the back surface 21b of the protective member 21 in contact with the upper surface 8a of the holding plate 8, the back surface 21b of the protective member 21 is sucked by the chuck table 4. In other words, the workpiece 11 is held on the chuck table 4 via the protective member 21 so that the back surface 11b is exposed upward.

[0025] A rotary drive source (not shown), such as a motor, is connected to the lower part of the frame 6. The force generated by this rotary drive source causes the chuck table 4 to rotate about an axis along the vertical direction or an axis slightly tilted relative to the vertical direction, with the center 8b of the upper surface 8a being the center of rotation. The frame 6 is also supported by a chuck table moving mechanism (not shown), typically a turntable that can be rotated by a rotary drive source such as a motor, and the force generated by this chuck table moving mechanism causes the chuck table 4 to move horizontally.

[0026] After the workpiece 11 is held by the chuck table 4 via the protective member 21, the workpiece 11 held by the chuck table 4 is ground from the back surface 11b side (grinding step). Figure 3 is a cross-sectional view that schematically shows how the workpiece 11 held by the chuck table 4 is ground. Note that, for the sake of convenience, side surfaces of some elements are shown in Figure 3.

[0027] As shown in FIG. 3, a grinding unit 10 is disposed at a position above the chuck table 4 of the processing device 2. The grinding unit 10 includes, for example, a cylindrical spindle housing (not shown). A columnar spindle 12 is housed in the space inside the spindle housing. A disk-shaped mount 14, for example, is provided at the lower end of the spindle 12. An annular grinding wheel 16 having approximately the same diameter as the mount 14 is fixed to the lower surface of the mount 14 with bolts (not shown) or the like.

[0028] The grinding wheel 16 includes an annular wheel base 18 made of a metal such as stainless steel or aluminum. A plurality of grinding stones 20 are fixed to the annular underside of the wheel base 18 along the circumferential direction of the wheel base 18. In other words, the plurality of grinding stones 20 are arranged in an annular shape. Each grinding stone 20 has a structure in which abrasive grains made of, for example, diamond or the like are dispersed in a binder made of, for example, resin.

[0029] A rotary drive source (not shown), such as a motor, is connected to the upper end of the spindle 12. The force generated by this rotary drive source causes the grinding wheel 16 to rotate about an axis that is aligned in the vertical direction or an axis that is slightly tilted relative to the vertical direction. The spindle housing is supported by, for example, a ball-screw type grinding unit movement mechanism (not shown), and the grinding unit 10 moves in the vertical direction due to the force generated by this grinding unit movement mechanism.

[0030] A grinding fluid supply nozzle 22 is disposed near the grinding wheel 16, which can supply a grinding fluid (grinding fluid) 31 such as water to the contact area between the workpiece 11 and the grinding stone 20. Instead of or together with this grinding fluid supply nozzle 22, a grinding fluid supply port used to supply the fluid 31 may be provided on the grinding wheel 16, etc.

[0031] When grinding the workpiece 11 with the grinding unit 10 (grinding wheel 16), the chuck table 4 first moves to a position directly below the grinding unit 10. More specifically, the chuck table moving mechanism adjusts the horizontal position of the chuck table 4 so that multiple grinding stones 20 pass through the space directly above the center 8b of the chuck table 4 when the grinding wheel 16 is rotated.

[0032] Thereafter, the chuck table 4 and the grinding wheel 16 each rotate, and the grinding unit 10 (grinding wheel 16) descends. That is, the grinding wheel 16 and the workpiece 11 move relatively in a vertical direction intersecting the back surface 11b of the workpiece 11 while rotating relative to each other. At this time, a grinding liquid 31 is supplied from the grinding fluid supply nozzle 22 to the workpiece 11, grinding wheel 20, etc. As a result, as shown in FIG. 3, the grinding wheel 20 comes into contact with the workpiece 11 from the back surface 11b side, and grinding of the workpiece 11 begins.

[0033] There are no significant limitations on the specific grinding conditions. For example, when the grinding wheel 20 is made of relatively large abrasive grains and the workpiece 11 is roughly ground with this grinding wheel 20, the rotation speed of the chuck table 4 is set to 100 rpm to 600 rpm, typically 300 rpm, the rotation speed of the grinding wheel 16 is set to 1000 rpm to 7000 rpm, typically 4500 rpm, and the speed of descent of the grinding unit 10 (grinding feed rate) is set to 1.0 μm / s to 10.0 μm / s, typically 6.0 μm / s.

[0034] Furthermore, when the grinding wheel 20 is made of relatively small abrasive grains and the workpiece 11 is ground with high precision using this grinding wheel 20, the rotation speed of the chuck table 4 is set to 100 rpm to 600 rpm, typically 300 rpm, the rotation speed of the grinding wheel 16 is set to 1000 rpm to 7000 rpm, typically 4000 rpm, and the descending speed of the grinding unit 10 is set to 0.1 μm / s to 1.5 μm / s, typically 0.5 μm / s.

[0035] Of course, the workpiece 11 may be ground using both a grinding wheel containing relatively large abrasive grains and a grinding wheel containing relatively small abrasive grains. That is, the workpiece 11 may be roughly ground using a grinding wheel containing relatively large abrasive grains, and then the workpiece 11 may be ground with high precision using a grinding wheel containing relatively small abrasive grains. When the workpiece 11 is thinned to a preset finishing thickness, the grinding unit 10 rises, and grinding of the workpiece 11 is completed.

[0036] When the workpiece 11 is ground, liquid 31 is supplied from the grinding fluid supply nozzle 22, and most of the debris generated during grinding is removed from the workpiece 11 and the chuck table 4 by this liquid 31. However, the grinding fluid supply nozzle 22 is configured primarily for the purpose of supplying liquid 31 to the area where the grinding wheel 20 and the workpiece 11 come into contact, and is not necessarily optimized for cleaning the workpiece 11 and the chuck table 4. Therefore, a small amount of debris may remain on the workpiece 11 and the chuck table 4.

[0037] In the composite processing device 2 having a structure in which grinding and polishing are performed successively, the workpiece 11 after grinding is moved while held on the chuck table 4, and is polished as is. However, if the workpiece 11 is polished while there is debris remaining on the workpiece 11 or the chuck table 4, the debris may scratch the workpiece 11, reducing the flatness of the polished surface.

[0038] Therefore, in this embodiment, after the workpiece 11 is ground, the grinding surface of the workpiece 11 held by the chuck table 4 and the chuck table 4 are cleaned (cleaning step). Fig. 4 is a cross-sectional view that schematically shows how the grinding surface 11c of the workpiece 11 and the chuck table 4 are cleaned. Note that for ease of explanation, Fig. 4 shows the side faces of some elements.

[0039] 4, a cleaning nozzle 24 used to clean the grinding surface 11c of the workpiece 11 and the chuck table 4 is disposed above the chuck table 4 of the processing device 2. The cleaning nozzle 24 is supported by, for example, a ball screw type nozzle swing mechanism (not shown), and can spray a cleaning fluid (cleaning fluid) 33 downward while moving horizontally by the force generated by this nozzle swing mechanism. As the cleaning fluid 33, for example, a mixed fluid (two-fluid) of water and air is used.

[0040] When the grinding surface 11c of the workpiece 11 and the chuck table 4 are cleaned with the cleaning nozzle 24, the chuck table 4 first moves to a position directly below the cleaning nozzle 24. More specifically, the chuck table moving mechanism adjusts the horizontal position of the chuck table 4 so that the nozzle swinging mechanism can swing the cleaning nozzle 24 between above the center 8b of the chuck table 4 and above the outer periphery of the chuck table 4.

[0041] Thereafter, for example, while the chuck table 4 is rotating at a rotation speed of about 10 rpm to 500 rpm, the cleaning nozzle 24 oscillates while spraying the fluid 33 at a high pressure of about 0.05 MPa to 0.15 MPa. As a result, the fluid 33 is sprayed onto the entire grinding surface 11c of the workpiece 11 and the exposed portion of the chuck table 4, and debris is sufficiently removed from the grinding surface 11c and the chuck table 4.

[0042] In this embodiment, a so-called two-fluid nozzle capable of spraying a mixed fluid of water and air is used as the cleaning nozzle 24, but a so-called water curtain nozzle capable of spraying a cleaning liquid (typically water) in a curtain-like manner to form a water curtain may also be used as the cleaning nozzle 24.

[0043] In this case, for example, the water curtain nozzle is fixed in a predetermined position and does not swing. As the chuck table 4 moves through the water curtain formed by the water curtain nozzle, the liquid is sprayed onto the entire grinding surface 11c of the workpiece 11 and the exposed portion of the chuck table 4, and debris is sufficiently removed from the grinding surface 11c and the chuck table 4.

[0044] The water curtain nozzle may be disposed near the boundary between the grinding area and the polishing area in the processing device 2. In this case, by forming a water curtain with the water curtain nozzle when grinding the workpiece 11, scattering of debris from the grinding area to the polishing area is suppressed.

[0045] After the grinding surface 11c of the workpiece 11 and the chuck table 4 have been cleaned, the workpiece 11 held by the chuck table 4 is polished from the grinding surface 11c side by a method such as chemical mechanical polishing (CMP) (polishing step). Figure 5 is a cross-sectional view that schematically shows how the workpiece 11 held by the chuck table 4 is polished. Note that for ease of explanation, Figure 5 shows the side faces of some elements.

[0046] As shown in Fig. 5, a polishing unit 26 is disposed at a position above the chuck table 4 of the processing device 2. The polishing unit 26 includes, for example, a cylindrical spindle housing (not shown). A columnar spindle 28 is housed in the space inside the spindle housing. A disk-shaped mount 30, for example, is provided at the lower end of the spindle 28. A disk-shaped polishing pad 32 is fixed to the underside of the mount 30 with a bolt (not shown) or the like.

[0047] The polishing pad 32 is formed in a disk shape from, for example, a nonwoven fabric or polymer foam that does not contain abrasive grains, and has a polishing liquid supply port (not shown) in the center that is used to supply a polishing liquid (polishing liquid) such as a chemical solution containing abrasive grains. The polishing liquid supply port is connected to a polishing liquid supply source via, for example, a flow path provided in the mount 30 or the spindle 28. The polishing pad 32 may contain abrasive grains. In this case, a chemical solution that does not contain abrasive grains is used as the polishing liquid.

[0048] A rotational drive source (not shown), such as a motor, is connected to the upper end of the spindle 28. The force generated by this rotational drive source causes the polishing pad 32 to rotate about an axis that is aligned vertically or slightly tilted relative to the vertical. The spindle housing is supported by, for example, a ball-screw type polishing unit movement mechanism (not shown), and the polishing unit 26 moves vertically due to the force generated by this polishing unit movement mechanism.

[0049] When the grinding surface 11c of the workpiece 11 is polished by the polishing unit 26 (polishing pad 32), the chuck table 4 first moves to a position directly below the polishing unit 26. More specifically, the chuck table moving mechanism adjusts the horizontal position of the chuck table 4 so that the entire grinding surface 11c of the workpiece 11 held on the chuck table 4 overlaps with the polishing pad 32 when viewed from above.

[0050] Thereafter, the chuck table 4 and the polishing pad 32 each rotate, and the polishing unit 26 (polishing pad 32) descends. That is, the polishing pad 32 and the workpiece 11 rotate relative to each other while moving relatively in a vertical direction intersecting with the grinding surface 11c of the workpiece 11. At this time, a polishing liquid is supplied to the workpiece 11, the polishing pad 32, etc. from the polishing liquid supply port.

[0051] 5, the polishing pad 32 comes into contact with the workpiece 11 from the side of the surface 11c to be ground, and polishing of the workpiece 11 begins. For convenience of explanation, FIG. 5 shows the polishing pad 32 in contact with part of the surface 11c to be ground, but as described above, the difference in height between the center 8b of the upper surface 8a of the chuck table 4 and the outer periphery of the upper surface 8a is small. Therefore, in reality, the polishing pad 32 comes into contact with the entire surface 11c to be ground.

[0052] There are no significant limitations on the specific polishing conditions. For example, the rotation speed of chuck table 4 is set to 10 rpm to 600 rpm, typically 500 rpm, the rotation speed of polishing pad 32 is set to 200 rpm to 600 rpm, typically 500 rpm, and the load applied from polishing pad 32 to workpiece 11 is set to 10 kPa to 35 kPa, typically 25 kPa. After a preset time has elapsed, polishing pad 32 rises, and polishing of workpiece 11 is completed.

[0053] In this embodiment, after the workpiece 11 is ground and before it is polished, the grinding surface 11c of the workpiece 11 and the chuck table 4 are cleaned, and debris generated during grinding is thoroughly removed from the grinding surface 11c and the chuck table 4. Therefore, the workpiece 11 is not scratched by debris remaining on the grinding surface 11c. Furthermore, the workpiece 11 is not scratched by debris remaining on the chuck table 4 being caught between the polishing pad 32 and the workpiece 11.

[0054] As described above, in the method for processing a workpiece according to this embodiment, after the workpiece 11 is ground with the grinding wheel 16, the grinding surface 11c of the workpiece 11 is cleaned together with the chuck table 4, and then the workpiece 11 is polished with the polishing pad 32. Therefore, when the workpiece 11 is polished with the polishing pad 32, debris generated during grinding has been sufficiently removed from the grinding surface 11c and the chuck table 4.

[0055] Therefore, even in a situation where grinding and polishing are performed successively, it is possible to prevent debris from getting caught between the polishing pad 32 and the workpiece 11, thereby achieving a high level of flatness on the polished surface. That is, according to the method for processing a workpiece according to this embodiment, it is possible to efficiently process the workpiece 11 while achieving a high level of flatness on the polished surface.

[0056] The present invention is not limited to the above-described embodiment and can be implemented with various modifications. For example, in the above-described embodiment, the cleaning nozzle 24 is swung horizontally by a nozzle swinging mechanism independent of the polishing unit moving mechanism, etc., but the polishing unit moving mechanism, etc. may also be used as the nozzle swinging mechanism.

[0057] 6 is a side view schematically illustrating a polishing unit moving mechanism 34, which is also used as a nozzle swinging mechanism. As shown in FIG. 6, the polishing unit moving mechanism 34 includes a pair of guide rails 36 that are generally parallel to the horizontal direction. The guide rails 36 are fixed to the front side of a columnar support structure (not shown), for example. A horizontally moving plate 38 is slidably attached to the guide rails 36.

[0058] A nut portion (not shown) constituting a ball screw is provided on the rear side of the horizontally moving plate 38, and a screw shaft 40 that is generally parallel to the guide rail 36 is rotatably connected to this nut portion. A rotational drive source 42 such as a motor is connected to one end of the screw shaft 40. By rotating the screw shaft 40 with the rotational drive source 42, the horizontally moving plate 38 moves along the guide rail 36.

[0059] A pair of guide rails 44 that are generally parallel to the vertical direction are fixed to the front side of the horizontally moving plate 38. A vertically moving plate 46 is attached to the guide rails 44 in a slidable manner.

[0060] A nut portion (not shown) constituting a ball screw is provided on the rear side of the vertical movement plate 46, and a screw shaft 48 that is generally parallel to the guide rail 44 is rotatably connected to this nut portion. A rotation drive source 50 such as a motor is connected to one end of the screw shaft 48. By rotating the screw shaft 48 with the rotation drive source 50, the vertical movement plate 46 moves along the guide rail 44.

[0061] A support 52 is provided on the front side of the vertically moving plate 46. A spindle housing 54 constituting the polishing unit 26 of the above-described embodiment is supported on the support 52. The base end side of the cleaning nozzle 24 of the above-described embodiment is also supported on the support 52. Therefore, the polishing unit moving mechanism 34 can swing the cleaning nozzle 24 together with the polishing unit 26 in the horizontal direction.

[0062] When the polishing unit moving mechanism 34 according to this modification is used, for example, when polishing the workpiece 11 (polishing step), the polishing unit moving mechanism 34 swings the polishing unit 26 in the horizontal direction. This allows the entire workpiece 11 to be polished evenly with the polishing pad 32, further improving the flatness of the polished surface.

[0063] Furthermore, when the workpiece 11 and the chuck table 4 are cleaned (cleaning step), the polishing unit moving mechanism 34 horizontally swings the cleaning nozzle 24. In other words, the cleaning nozzle 24 moves together with the polishing pad 32 while supplying cleaning fluid.

[0064] In addition, the structures, methods, etc. according to the above-described embodiments and modifications may be modified as appropriate without departing from the scope of the present invention. [Explanation of symbols]

[0065] 11: Workpiece 11a: Surface (first side) 11b: Back side (second side) 11c: Surface to be ground 13: Street (planned division line) 15: Device 21: Protective material 21a: Surface 21b: Back side 31: Liquid (grinding fluid) 33: Fluid (cleaning fluid) 2: Processing equipment 4: Chuck table 6: Frame 6a: Recess 6b: Flow path 8: Holding plate 8a:Top surface (holding surface) 8b: Center 10: Grinding unit 12: Spindle 14: Mount 16: Grinding wheel 18: Wheel base 20: Grinding wheel 22: Grinding fluid supply nozzle 24: Cleaning nozzle 26: Polishing unit 28: Spindle 30: Mount 32: Polishing pad 34: Polishing unit movement mechanism 36: Guide rail 38: Horizontal moving plate 40: Screw shaft 42: Rotation drive source 44: Guide rail 46: Vertical moving plate 48: Screw shaft 50: Rotation drive source 52: Support 54: Spindle housing

Claims

1. A method for processing a workpiece that is applied when processing a plate-shaped workpiece having a first surface and a second surface opposite to the first surface, a grinding step of grinding the workpiece from the second surface side with a grinding wheel; a cleaning step of cleaning the ground surface of the workpiece after the grinding step; a polishing step of polishing the workpiece from the grinding surface side with a polishing pad after the cleaning step, In the cleaning step, a cleaning nozzle is moved together with the polishing pad while a cleaning fluid is supplied from the cleaning nozzle.

2. A method for processing a workpiece that is applied when processing a plate-shaped workpiece having a first surface and a second surface opposite to the first surface, a holding step of holding the first surface side of the workpiece on a chuck table; a grinding step of grinding the workpiece held by the chuck table from the second surface side with a grinding wheel after the holding step; a cleaning step of cleaning the grinding surface of the workpiece held by the chuck table together with the chuck table after the grinding step; a polishing step of polishing the workpiece held by the chuck table from the grinding surface side with a polishing pad after the cleaning step, In the cleaning step, a cleaning nozzle is moved together with the polishing pad while a cleaning fluid is supplied from the cleaning nozzle.

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