Polishing method for workpieces

Abstract

To provide a polishing method of a workpiece which does not cause a large difference between thicknesses of an external peripheral part of a circular disc-shaped subject and the other portion.SOLUTION: A polishing method of a subject includes: a first holding step for holding a circular disc-shaped plate whose diameter is larger than that of the subject by a first holding face of a first chuck table; an auxiliary ring forming step for forming an auxiliary ring having a circular opening part which can accommodate the subject by rotating the first chuck table by notching a cutting blade into the plate which is held by the first chuck table; a second holding step for holding the subject and the auxiliary ring by a second holding face of a second chuck table; and a polishing step for polishing the subject and the auxiliary ring by bringing a rotated polishing pad into contact with the subject and the auxiliary ring while rotating the second chuck table.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for polishing a workpiece when polishing a disk-shaped workpiece.

Background Art

[0002] In order to realize a small and lightweight device chip, there is an increasing opportunity to thinly process a disk-shaped wafer on which a device such as an integrated circuit is provided on the surface side. For example, the surface side of the wafer is held by a chuck table, and a grinding wheel fixed with a grinding stone containing abrasive grains and the chuck table 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, whereby the wafer is ground and thinned.

[0003] By the way, when the wafer is ground with a grinding stone containing abrasive grains as described above, fine scratches and distortions are generated on the surface to be ground, and the mechanical strength (for example, flexural strength) of the wafer is likely to be insufficient. Therefore, after the wafer is ground, in order to remove the fine scratches and distortions generated on the surface to be ground, the entire surface to be ground is polished with a soft polishing pad made of a non-woven fabric or a polymer foam (such as foamed polyurethane).

[0004] This polishing pad is generally configured in a disk shape larger than the wafer so as to be able to contact the entire surface to be ground. Therefore, when the entire surface to be ground is polished with the polishing pad, a part of the polishing pad wraps around from the surface to be ground to the outer peripheral side of the wafer, and the wafer is also polished from this outer peripheral side. As a result, the outer peripheral portion of the wafer becomes thinner than other portions, and the quality of the device chip may deteriorate.

[0005] To solve this problem, a method has been proposed in which the wafer is cut at the boundary between the device region where the device is located and the annular outer peripheral excess region surrounding the device region, and then the device region is polished together with the cut annular outer peripheral excess region (see, for example, Patent Document 1). In this method, the polishing pad is supported by the annular outer peripheral excess region cut from the wafer, making it difficult for the polishing pad to wrap around to the outer periphery of the device region. In other words, it becomes less likely for there to be a difference in thickness between the outer periphery of the device region and other parts of it. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2011-124262 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, in typical wafers, the width of the annular outer periphery is extremely narrow in order to ensure a sufficiently large device area. In such cases, even if the device area is polished together with the cut annular outer periphery, a large difference in thickness can occur between the outer periphery of the device area and other parts.

[0008] Therefore, the object of the present invention is to provide a novel method for polishing a workpiece that does not cause a large difference in thickness between the outer circumference of a disc-shaped workpiece and other parts of it. [Means for solving the problem]

[0009] According to one aspect of the present invention, a method for polishing a workpiece that is applied when polishing a disc-shaped workpiece, comprising: a first holding step of holding a disc-shaped plate with a larger diameter than the workpiece on the first holding surface of a first chuck table configured to rotate on a rotation axis intersecting the first holding surface; and rotating the first chuck table by cutting a cutting blade, which is rotated on a rotation axis intersecting the rotation axis of the first chuck table, into the plate held on the first chuck table, thereby polishing an auxiliary chuck having a circular opening in which the workpiece can be accommodated. A method for polishing a workpiece is provided, comprising: an auxiliary ring forming step of forming an auxiliary ring; a second holding step of holding the workpiece and the auxiliary ring on the second holding surface of a second chuck table configured to rotate on a rotation axis intersecting the second holding surface, such that the workpiece is accommodated in the opening of the auxiliary ring; and a polishing step of polishing the workpiece and the auxiliary ring by bringing a polishing pad, which is rotated on a rotation axis intersecting the second holding surface, into contact with the workpiece and the auxiliary ring while rotating the second chuck table.

[0010] Preferably, in the auxiliary ring forming step, In the radial direction An auxiliary ring having a width of 3 mm to 30 mm is formed. Preferably, in the auxiliary ring forming step, the auxiliary ring is formed such that the difference between the diameter of the workpiece and the diameter of the opening is 1 mm to 2 mm. Preferably, the material of the plate that forms the auxiliary ring is the same as the material of the workpiece. [Effects of the Invention]

[0011] In a workpiece polishing method according to one aspect of the present invention, an auxiliary ring having a circular opening capable of accommodating the workpiece is formed from a disc-shaped plate with a larger diameter than the disc-shaped workpiece, and the workpiece is polished using this auxiliary ring. As a result, an auxiliary ring with a width suitable for polishing the workpiece can be obtained, and a large difference in thickness between the outer circumference of the workpiece and other parts of it can be avoided.

[0012] Furthermore, in a workpiece polishing method relating to one aspect of the present invention, a plate with a larger diameter than the workpiece is held in the first chuck table, and then a cutting blade is made to cut into the plate held in the first chuck table, and the first chuck table is rotated to form an auxiliary ring, so that an auxiliary ring with a width suitable for polishing the workpiece can be easily obtained. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a schematic perspective view showing a disc-shaped workpiece. [Figure 2] Figure 2 is a schematic perspective view showing a disc-shaped plate. [Figure 3] Figure 3 is a schematic perspective view showing how an auxiliary ring is formed from a plate. [Figure 4] Figure 4 is a schematic perspective view showing how the support members are attached to the workpiece and the auxiliary ring. [Figure 5] Figure 5 is a schematic cross-sectional view showing the polishing process of the workpiece and the auxiliary ring. [Figure 6] Figure 6 is a schematic cross-sectional view showing the workpiece and auxiliary ring after polishing. [Modes for carrying out the invention]

[0014] Embodiments of the present invention will be described below with reference to the attached drawings. Figure 1 is a schematic perspective view showing a disc-shaped workpiece 11 that is polished (polished) by the polishing method of the workpiece according to this embodiment. As shown in Figure 1, the workpiece 11 is a disc-shaped wafer made mainly of a semiconductor such as silicon (Si), and has a circular surface 11a, a circular back surface 11b opposite to the surface 11a, and an outer peripheral surface 11c connecting the surface 11a and the back surface 11b.

[0015] On the surface 11a side of the workpiece 11, it is partitioned into a plurality of small regions by a plurality of streets (lines to be divided) 13 that intersect each other, and devices 15 such as integrated circuits (ICs) are formed in each small region. In a part of the region including the outer peripheral surface 11c of the workpiece 11, a notch portion 11d called a notch or the like is provided to indicate the orientation (crystal orientation, etc.) of the workpiece 11.

[0016] The back surface 11b side of this workpiece 11 has already been ground with a grinding wheel containing abrasive grains, and fine scratches and distortions have occurred on the back surface 11b of the workpiece 11. In the present embodiment, in order to remove the fine scratches and distortions remaining on the back surface 11b of the workpiece 11, the entire back surface 11b is polished with a soft polishing pad.

[0017] In the present embodiment, a disk-shaped wafer containing a semiconductor such as silicon as a main material is used as the workpiece 11, but the material, shape, structure, size, etc. of the workpiece 11 are not limited to this mode. For example, a substrate or the like containing other semiconductors, ceramics, resins, metals, etc. as main materials can be used as the workpiece 11.

[0018] Similarly, the type, quantity, shape, structure, size, arrangement, etc. of the devices 15 are not limited to the above-described mode. The workpiece 11 may not have the devices 15, the notch portion 11d, etc. formed thereon. Also, the back surface 11b side of the workpiece 11 does not necessarily have to be ground with a grinding wheel containing abrasive grains.

[0019] In the polishing method of the workpiece of the present embodiment, first, an auxiliary ring used when polishing the workpiece 11 as described above is formed. FIG. 2 is a perspective view schematically showing a disk-shaped plate 21 to be processed into an auxiliary ring, and FIG. 3 is a perspective view schematically showing a state in which the auxiliary ring 31 is formed from the plate 21.

[0020] As shown in FIG. 2, the plate 21 is configured as a disk having a diameter D2 larger than the diameter D1 (see FIG. 1) of the workpiece 11, and has a circular surface 21a, a circular back surface 21b on the side opposite to the surface 21a, and an outer peripheral surface 21c connecting the surface 21a and the back surface 21b. In this embodiment, the thickness of the plate 21 is adjusted to be approximately the same as the thickness of the workpiece 11.

[0021] However, the thickness of the plate 21 is not limited to this, and it may be within a range where the back surface 11b of the workpiece 11 can be appropriately polished. For example, when a protective member such as a back grind tape is attached only to the surface 11a side of the workpiece 11 and the back surface 11b of the workpiece 11 is polished in that state, considering the thickness of the protective member, etc., the height of the back surface 11b of the workpiece 11 during polishing and the height of the polished surface (upper surface) of the auxiliary ring formed from the plate 21 are made to be approximately the same (the height difference is 10 μm or less), and the thickness of the plate 21 is determined.

[0022] Typically, the plate 21 is made of the same material as the workpiece 11. Specifically, the main material constituting the plate 21 is the same as the main material constituting the workpiece 11. Therefore, the auxiliary ring formed from the plate 21 is polished in the same manner as the workpiece 11. However, as long as the auxiliary ring formed from the plate 21 can be polished in the same manner as the workpiece 11, the main material constituting the plate 21 may be different from the main material constituting the workpiece 11.

[0023] When forming the auxiliary ring 31 from the plate 21, for example, the cutting device 2 shown in FIG. 3 is used. The cutting device 2 includes a first chuck table 4 configured to hold the plate 21. The first chuck table 4 includes, for example, a disk-shaped frame made of a metal typified by stainless steel. A recess having a circular opening at the upper end is provided on the upper surface side of the frame. A holding plate configured as a porous disk using ceramics or the like is fixed to this recess.

[0024] A first holding surface 4a for holding the plate 21 is formed by the upper surface of the frame and the upper surface of the holding plate. The lower side of the holding plate is connected to a suction source such as an ejector via a flow path provided inside the frame or a valve located outside the frame. Therefore, by bringing the back surface 21b of the plate 21 into contact with the first holding surface 4a, opening the valve, and applying negative pressure from the suction source, the plate 21 is held on the first chuck table 4 by the suction force of the negative pressure.

[0025] A rotational drive source (not shown), such as a motor, is connected to the lower part of the frame, and the first chuck table 4 rotates around a rotation axis that intersects the first holding surface 4a approximately perpendicularly, powered by this rotational drive source. The frame is also supported by, for example, a first chuck table moving mechanism (not shown), and the first chuck table 4 moves along a first feed direction that is approximately parallel to the first holding surface 4a, powered by this first chuck table moving mechanism.

[0026] A cutting unit 6 is positioned above the first chuck table 4. The cutting unit 6 is equipped with a cylindrical spindle housing 8. A columnar spindle (not shown) is housed in the space inside the spindle housing 8. The axis (rotation axis) of this spindle is approximately parallel to the first holding surface 4a of the first chuck table 4. In other words, the axis (rotation axis) of the spindle intersects with the rotation axis of the first chuck table 4.

[0027] One end of the spindle is exposed to the outside from the spindle housing 8. A cutting blade 10, which has a cutting edge containing abrasive grains, is mounted on this one end of the spindle. A rotational drive source (not shown), such as a motor, is connected to the other end of the spindle, and the cutting blade 10 mounted on the one end of the spindle rotates around the axis of the spindle by the power generated by this rotational drive source. A nozzle (not shown) is positioned next to the cutting blade 10, which can supply liquid such as water to the cutting blade 10 or the plate 21.

[0028] The spindle housing 8 is supported, for example, by a cutting unit moving mechanism (not shown), and the cutting unit 6 moves along a second feed direction that is generally parallel to the first holding surface 4a and generally perpendicular to the first feed direction, and a third feed direction that is generally perpendicular to the first holding surface 4a, by the power of this cutting unit moving mechanism.

[0029] When forming the auxiliary ring 31, the plate 21 is first held by the first holding surface 4a of the first chuck table 4 (first holding step). Specifically, for example, the back surface 21b of the plate 21 is brought into contact with the first holding surface 4a, and the valve is opened while the suction source is operating. As a result, the plate 21 is held by the suction force of the negative pressure on the first chuck table 4, and the surface 21a is exposed upwards. Note that a support member such as dicing tape may be attached to the back surface 21b of the plate 21 in advance.

[0030] After the plate 21 is held by the first holding surface 4a of the first chuck table 4, an auxiliary ring (annular auxiliary member) 31 is formed by cutting into the plate 21 with the rotating cutting blade 10 (auxiliary ring formation step). Specifically, first, the relationship between the position of the first chuck table 4 and the position of the cutting unit 6 is adjusted in the first and second feed directions so that the cutting blade 10 is positioned above the circular cutting line 21d centered on the rotation axis of the first chuck table 4. This adjustment is performed by the first chuck table moving mechanism and the cutting unit moving mechanism.

[0031] Next, the rotation of the cutting blade 10 (spindle) and the supply of liquid from the nozzle are started. Then, the position of the cutting unit 6 in the vertical direction is adjusted by the cutting unit moving mechanism so that the position (height) of the lower end of the cutting blade 10 is slightly lower than the position (height) of the back surface 11b of the plate 21.

[0032] Subsequently, the first chuck table 4 rotates. In other words, in this embodiment, the cutting blade 10, which is rotating on an axis of rotation intersecting the axis of rotation of the first chuck table 4, cuts into the plate 21 held by the first chuck table 4, while the first chuck table 4 rotates around its axis of rotation. When the amount of rotation of the first chuck table 4 exceeds one full rotation (360°), the plate 21 is cut along the planned cutting line 21d and separated into an auxiliary ring 31 and a disc-shaped waste material 33.

[0033] Here, it is desirable that the diameter D3 of the circular cutting line 21d be set such that the diameter of the opening 31d of the auxiliary ring 31 (see Figure 4) is larger than the diameter D1 of the workpiece 11 by a length of 1 mm to 2 mm. Typically, the diameter D3 of the cutting line 21d is set such that the difference between the diameter D1 of the workpiece 11 and the diameter D3 of the cutting line 21d is 1 mm to 2 mm.

[0034] Furthermore, it is desirable that the diameter D2 of the plate 21 be set such that an auxiliary ring 31 with a width (distance from the outer edge to the inner edge) of 3 mm or more is obtained. In this embodiment, the diameter D2 of the plate 21 and the diameter D3 of the cutting line 21d are set such that the difference between the diameter D2 of the plate 21 and the diameter D3 of the cutting line 21d is 3 mm or more and 30 mm or less. As a result, an auxiliary ring 31 with a width of 3 mm or more and 30 mm or less can be obtained simply by cutting the plate 21 along the cutting line 21d.

[0035] However, the diameter D2 of the plate 21 may be set such that the difference between it and the diameter D3 of the planned cutting line 21d is greater than 30 mm. In this case, the plate 21 is further cut along another planned cutting line set radially outside the planned cutting line 21d in order to obtain an auxiliary ring 31 of the desired width.

[0036] When an auxiliary ring 31 of this size is used, the polishing pad is supported by the auxiliary ring 31 in an area outside the outer circumference of the workpiece 11, making it difficult for the pad to wrap around to the outer circumference of the workpiece 11. This ensures proper polishing of the workpiece 11. A portion of the surface 21a of the plate 21 becomes the surface 31a of the auxiliary ring 31, a portion of the back surface 21b of the plate 21 becomes the back surface 31b of the auxiliary ring 31, and the outer circumference 21c of the plate 21 becomes the outer circumference 31c of the auxiliary ring 31.

[0037] After the auxiliary ring 31 is formed, the workpiece 11 is polished using the auxiliary ring 31 by a method such as chemical mechanical polishing (CMP). In this embodiment, support members are attached to the workpiece 11 and the auxiliary ring 31 so that an appropriate positional relationship is achieved between the workpiece 11 and the auxiliary ring 31 (support member attachment step). Figure 4 is a schematic perspective view showing how the support members 41 are attached to the workpiece 11 and the auxiliary ring 31.

[0038] The support member 41 is typically a circular tape (film), resin substrate, etc., having a diameter approximately equal to the diameter of the outer edge of the auxiliary ring 31 (i.e., the diameter of the circle formed by the outer peripheral surface 31c). In other words, the support member 41 has a circular surface 41a and a circular back surface 41b opposite to the surface 41a. An adhesive layer is provided on the surface 41a side of the support member 41, which exhibits adhesive force to the workpiece 11 and the auxiliary ring 31.

[0039] Therefore, as shown in Figure 4, when the surface 41a side of the support member 41 is brought into close contact with the surface 11a of the workpiece 11 and the back surface 31b of the auxiliary ring 31, the support member 41 is attached to the surface 11a of the workpiece 11 and the back surface 31b of the auxiliary ring 31. In this embodiment, the support member 41 is attached to the workpiece 11 and the auxiliary ring 31 with the positional relationship between the workpiece 11 and the auxiliary ring 31 adjusted so that the workpiece 11 is accommodated in the opening 31d of the auxiliary ring 31. As a result, the positional relationship between the workpiece 11 and the auxiliary ring 31 is fixed by the support member 41.

[0040] After the support member 41 is attached to the workpiece 11 and the auxiliary ring 31, the workpiece 11 and the auxiliary ring 31 are polished. Figure 5 is a schematic cross-sectional view showing the polishing of the workpiece 11 and the auxiliary ring 31. When polishing the workpiece 11 and the auxiliary ring 31, for example, the polishing device 22 shown in Figure 5 is used.

[0041] The polishing apparatus 22 includes a second chuck table 24 configured to hold the workpiece 11 and the auxiliary ring 31. The second chuck table 24 includes a disc-shaped frame 26 made of, for example, ceramics. A recess 26b having a circular opening at its upper end is provided on the upper surface 26a side of the frame 26. A porous disc-shaped holding plate 28 made of ceramics or the like is fixed to this recess 26b.

[0042] A second holding surface 24a for holding the workpiece 11 and the auxiliary ring 31 is formed by the upper surface 26a of the frame 26 and the upper surface 28a of the holding plate 28. The lower side of the holding plate 28 is connected to a suction source such as an ejector via a flow path provided inside the frame 26 or a valve located outside the frame 26. Therefore, by bringing the back surface 41b of the support member 41 into contact with the second holding surface 24a, opening the valve, and applying negative pressure from the suction source, the support member 41 is held on the second chuck table 24 by the suction force of the negative pressure.

[0043] A rotational drive source (not shown), such as a motor, is connected to the lower part of the frame 26, and the second chuck table 24 rotates around a rotation axis that intersects the second holding surface 24a approximately perpendicularly, powered by this rotational drive source. The frame 26 is also supported by, for example, a second chuck table moving mechanism (not shown), and the second chuck table 24 moves along a direction approximately parallel to the second holding surface 24a, powered by this second chuck table moving mechanism.

[0044] A polishing unit 30 is positioned above the second chuck table 24. The polishing unit 30 includes, for example, a cylindrical spindle housing (not shown). A columnar spindle 32 is housed in the space inside the spindle housing. The axis (rotation axis) of the spindle 32 intersects with the second holding surface 24a of the second chuck table 24.

[0045] The lower end of the spindle 32 is exposed to the outside from the spindle housing. A disc-shaped mount 34 is fixed to this lower end of the spindle 32, for example. A disc-shaped polishing pad 36 is attached to the lower surface of the mount 34 by bolts (not shown) or the like.

[0046] The polishing pad 36 is constructed in a disc shape from, for example, a nonwoven fabric or polymer foam (such as foamed polyurethane) that does not contain abrasive particles, and has a polishing fluid supply port (not shown) in its center for supplying a polishing liquid (polishing fluid) containing abrasive particles. The polishing fluid supply port is connected to a polishing fluid supply source via a flow path provided in the mount 34 or spindle 32. The polishing pad 36 may contain abrasive particles. In that case, a liquid that does not contain abrasive particles is used as the polishing fluid.

[0047] A rotational drive source (not shown), such as a motor, is connected to the upper end of the spindle 32, and the polishing pad 36, which is mounted on the lower end of the spindle 32 via a mount 34, rotates around the axis of the spindle 32 by the power generated by this rotational drive source. The spindle housing is supported by, for example, a ball screw type polishing unit moving mechanism (not shown), and the polishing unit 30 moves along a direction that is roughly perpendicular to the second holding surface 24a by the power generated by this polishing unit moving mechanism.

[0048] When polishing the workpiece 11 together with the auxiliary ring 31, first, the workpiece 11 and the auxiliary ring 31 are held by the second holding surface 24a of the second chuck table 24 (second holding step). Specifically, for example, the back surface 41b of the support member 41 is brought into contact with the second holding surface 24a, and the valve is opened while the suction source is operating. As a result, the support member 41 is held on the second chuck table 24 by the suction force of the negative pressure. In other words, the workpiece 11 and the auxiliary ring 31 are held on the second chuck table 24 via the support member 41.

[0049] After the workpiece 11 and the auxiliary ring 31 are held by the second holding surface 24a of the second chuck table 24, the workpiece 11 and the auxiliary ring 31 are polished by bringing the rotating polishing pad 36 into contact with the workpiece 11 and the auxiliary ring 31 (polishing step). Specifically, first, the second chuck table 24 moves directly below the polishing unit 30. More specifically, the second chuck table moving mechanism adjusts the horizontal position of the second chuck table 24 so that the entire workpiece 11 held by the second chuck table 24 overlaps with the polishing pad 36 when viewed from above.

[0050] Subsequently, the second chuck table 24 and the polishing pad 36 rotate, causing the polishing unit 30 (polishing pad 36) to descend. In other words, with the polishing pad 36 and the workpiece 11 rotating relative to each other, the polishing unit moving mechanism moves the polishing unit 30 along a direction that is roughly perpendicular to the second holding surface 24a. At this time, polishing liquid is supplied from the polishing liquid supply port to the workpiece 11, the auxiliary ring 31, the polishing pad 36, etc.

[0051] As a result, as shown in Figure 5, the polishing pad 36 contacts the entire back surface 11b of the workpiece 11 and the surface 31a of the auxiliary ring 31 from above, polishing both the back surface 11b of the workpiece 11 and the surface 31a of the auxiliary ring 31. In this embodiment, the auxiliary ring 31 is positioned to surround the workpiece 11. Therefore, the polishing pad 36 is supported by the auxiliary ring 31 in an area outside the outer circumference of the workpiece 11, making it difficult for it to wrap around to the outer circumference of the workpiece 11. Consequently, the outer circumference of the workpiece 11 does not become significantly thinner than other parts of the workpiece 11.

[0052] Furthermore, in order to sufficiently prevent the polishing pad 36 from wrapping around the outer circumference of the workpiece 11, it is desirable that the gap between the workpiece 11 and the auxiliary ring 31 be adjusted to 0.5 mm or more and 1 mm or less around the entire circumference of the workpiece 11. In other words, it is desirable that the support member 41 be attached to the workpiece 11 and the auxiliary ring 31 after the positional relationship between the workpiece 11 and the auxiliary ring 31 has been adjusted to achieve the above-mentioned gap. This ensures that the thickness of the outer circumference of the workpiece 11 is generally uniform around its entire circumference.

[0053] As described above, in the workpiece polishing method according to this embodiment, an auxiliary ring (annular auxiliary member) 31 having a circular opening 31d capable of accommodating the workpiece 11 is formed from a disc-shaped plate 21 with a larger diameter than the disc-shaped workpiece 11, and the workpiece 11 is polished using this auxiliary ring 31. As a result, an auxiliary ring 31 with a width suitable for polishing the workpiece 11 can be obtained, and a large difference in thickness between the outer circumference of the workpiece 11 and other parts can be avoided.

[0054] Furthermore, in the workpiece polishing method according to this embodiment, a plate 21 with a larger diameter than the workpiece 11 is held in the first chuck table 4, and then the cutting blade 10 is made to cut into the plate 21 held in the first chuck table 4 and the first chuck table 4 is rotated to form an auxiliary ring 31. Thus, an auxiliary ring 31 with a width suitable for polishing the workpiece 11 can be easily obtained.

[0055] It should be noted that the present invention is not limited to the embodiments described above and can be implemented with various modifications. For example, in the embodiments described above, the support member 41 is attached to the workpiece 11 and the auxiliary ring 31, and the workpiece 11 and the auxiliary ring 31 are polished in an integrated state via the support member 41. However, the support member 41 does not need to be attached to the workpiece 11 and the auxiliary ring 31.

[0056] In this case, for example, a second chuck table may be used that independently comprises a first holding part capable of sucking and holding the workpiece 11 and a second holding part capable of sucking and holding the auxiliary ring 31. By using a second chuck table with such a structure, the workpiece 11 and the auxiliary ring 31 are securely held by a common second chuck table, so that the workpiece 11 can be properly polished even if support members 41 are not attached to the workpiece 11 and the auxiliary ring 31.

[0057] Furthermore, in the embodiment described above, a cutting device 2 including a first chuck table 4 and a cutting unit 6, and a polishing device 22 including a second chuck table 24 and a polishing unit 30 are used in combination, but a processing device in which these are integrated may also be used. In that case, the first chuck table 4 may be used as the second chuck table 24, or the second chuck table 24 may be used as the first chuck table 4. In other words, one of the first chuck table 4 or the second chuck table 24 may be omitted.

[0058] Furthermore, the structures, methods, etc., of the embodiments and modified versions described above may be modified as appropriate, as long as they do not deviate from the scope of the present invention. [Explanation of Symbols]

[0059] 11: Workpiece 11a: Surface 11b: Back side 11c: Outer surface 11d: Notch 13: Street (planned division line) 15: Device 21: Board 21a: Surface 21b: Back side 21c: Outer surface 21d: Cutting line 31: Auxiliary ring (annular auxiliary member) 31a: Surface 31b: Back side 31c: Outer surface 31d: opening 33: Scrap materials 2:Cutting device 4: First Chuck Table 4a: 1st holding surface 6: Cutting Unit 8: Spindle housing 10: Cutting blade 22: Polishing equipment 24: Second Chuck Table 24a: 2nd holding surface 26:Frame body 26a:Top surface 26b: recess 28: Holding plate 28a:Top surface 30: Polishing unit 32: Spindle 34: Mount 36: Polishing pad 41: Support member 41a: Surface 41b: Back side

Claims

1. A method for polishing a workpiece that is applied when polishing a disc-shaped workpiece, A first holding step involves holding a disc-shaped plate with a larger diameter than the workpiece at the first holding surface of a first chuck table configured to rotate on a rotation axis intersecting the first holding surface, The auxiliary ring forming step involves forming an auxiliary ring having a circular opening capable of accommodating the workpiece by rotating a cutting blade on a rotation axis intersecting the rotation axis of the first chuck table and cutting into the plate held in the first chuck table, thereby rotating the first chuck table, and A second holding step is to hold the workpiece and the auxiliary ring on the second holding surface of a second chuck table configured to rotate on a rotation axis intersecting the second holding surface, such that the workpiece is accommodated in the opening of the auxiliary ring. A method for polishing a workpiece, comprising a polishing step of polishing the workpiece and the auxiliary ring by rotating the second chuck table and bringing a polishing pad, which is rotated on a rotation axis intersecting the second holding surface, into contact with the workpiece and the auxiliary ring.

2. The method for polishing a workpiece according to claim 1, wherein the auxiliary ring forming step involves forming an auxiliary ring having a width of 3 mm or more and 30 mm or less in the radial direction.

3. The method for polishing a workpiece according to claim 1 or claim 2, wherein in the auxiliary ring forming step, an auxiliary ring is formed such that the difference between the diameter of the workpiece and the diameter of the opening is 1 mm or more and 2 mm or less.

4. The method for polishing a workpiece according to claim 1 or claim 2, wherein the main material constituting the plate that forms the auxiliary ring is the same as the main material constituting the workpiece.

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