Method for processing wafer

Abstract

(Problem) Provides a wafer processing method that can solve problems caused by processing debris attached to the side of a device chip. (Solution) A wafer processing method comprises: a splitting point forming process for forming a splitting point on a splitting line; a protective member placement process for placing a protective member that protects the surface of the wafer; a backside grinding process for grinding the backside of the wafer to finish it to a desired thickness and forming a splitting groove on a splitting line to split the wafer into device chips; a sheet placement process for placing a stretchable sheet on the backside of the wafer and removing a protective member from the surface of the wafer; an adhesive coating process for coating a fluid adhesive on the surface of the wafer; a sheet stretching process for stretching the sheet to infiltrate the adhesive into the splitting groove and discharge the adhesive from the splitting groove; and a cleaning process for removing the adhesive from the surface of the wafer and cleaning the side of the splitting groove.

Description

Technology Field

[0001] The present invention relates to a method for processing a wafer, wherein the wafer formed on the surface is divided into individual device chips by partitioning a plurality of planned division lines in which a plurality of devices intersect. Background Technology

[0002] A wafer formed on the surface by being partitioned by multiple planned division lines where multiple devices such as ICs and LSIs intersect, is formed to a desired thickness by grinding the back surface, then divided into individual device chips by a dicing device and a laser processing device, and each divided device chip is used in electrical devices such as mobile phones and personal computers.

[0003] In addition, the applicant has proposed a technology for dividing the wafer into individual device chips by positioning a point of focus of a laser beam of a wavelength that is permeable to the wafer inside the wafer corresponding to a line to be divided, irradiating the wafer with the laser beam to form a modified layer that serves as a starting point for division, and then grinding the back surface of the wafer to finish it to a desired thickness (see, for example, Patent Document 1).

[0004] In the technology described in Patent Document 1, since the focusing point of the laser beam is positioned inside the wafer before grinding (i.e., a wafer with a relatively thick thickness), there is an advantage in that a modified layer can be appropriately formed inside the line to be divided. In addition, if the thickness of the wafer is excessively thin, it becomes difficult to position the focusing point of the laser beam inside the wafer corresponding to the line to be divided, and there may be a region where a modified layer is not formed inside the wafer corresponding to the line to be divided.

[0005] In addition, the technology described in Patent Document 1 has the advantage of being able to form a wafer to a desired thickness, and in addition, during grinding, the crack extending from the modified layer to the surface is extended and the wafer is divided into individual device chips by cleavage, so the flexural strength of the device chips can be increased even when the wafer is finished thin. Prior art literature

[0006] Patent Document 1: Japanese Published Patent Application No. 2014-78569 The problem to be solved

[0007] However, there are times when machining debris generated during grinding enters the splitting grooves formed in the planned splitting line and adheres to the sides of the device chips. In such cases, there is a problem in that the machining debris falling and scattering from the sides of the device chips interferes with bonding during subsequent processes such as wire bonding, die bonding, and device chip stacking, and also adheres to the surface of the device chips, thereby damaging the stacked device chips.

[0008] This problem may also occur in a technique called pre-dicing, in which a groove of a depth corresponding to the finishing thickness of the device chip is formed on a line scheduled for division as a starting point for division, and the back surface of the wafer is ground until the finishing thickness of the device chip is reached to divide the wafer into individual device chips (see, for example, Japanese Patent Publication No. Hei 11-40520).

[0009] Accordingly, the objective of the present invention is to provide a method for processing a wafer that can solve the problem caused by processing debris attached to the side of a device chip. means of solving the problem

[0010] According to the present invention, a method for processing a wafer, wherein the wafer formed on the surface is partitioned by a plurality of planned division lines intersecting a plurality of devices and divided into individual device chips, comprises: a division starting point forming process for forming a division starting point on the planned division lines; a protective member placement process for placing a protective member that protects the surface of the wafer before or after the division starting point forming process; a backside grinding process for dividing the wafer into individual device chips by maintaining the side of the protective member on a chuck table and grinding the backside of the wafer to finish it to a desired thickness while forming a division groove on the planned division lines; a sheet placement process for removing the protective member from the surface of the wafer while placing a stretchable sheet on the backside of the wafer; an adhesive liquid coating process for coating a fluid adhesive liquid onto the surface of the wafer; a sheet stretching process for stretching the sheet placed in the sheet placement process to expand the width of the division groove to allow the adhesive liquid to penetrate into the division groove while reducing the width of the division groove to discharge the adhesive liquid from the division groove; and removing the adhesive liquid from the surface of the wafer so as to at least the A method for processing a wafer is provided, comprising a cleaning process for cleaning the side of a split groove.

[0011] Preferably, in the process of forming the division starting point, a focusing point of a laser beam of a wavelength that is transparent to the wafer is positioned inside the wafer corresponding to the line to be divided, and the laser beam is irradiated onto the wafer to form a modified layer that serves as the starting point for division.

[0012] Preferably, in the process of forming the splitting point, a groove with a depth corresponding to the finishing thickness of the device chip is formed on the line scheduled for splitting to serve as the splitting point.

[0013] The above protective member placement process may be performed after the above division point formation process.

[0014] Preferably, the adhesive used in the adhesive coating process comprises any one of polyvinyl alcohol, polyethylene oxide, polyacrylamide, carboxymethylcellulose, resol-type phenolic resin, methylolated urea resin, or methylolated melamine resin, and in the cleaning process, cleaning water is supplied to remove the adhesive. Effects of the invention

[0015] According to the wafer processing method of the present invention, processing debris attached to the side of a device chip is captured by a fluid adhesive, and then the side of the dividing groove is cleaned, thereby removing the processing debris along with the adhesive from the side of the device chip. Accordingly, problems caused by processing debris attached to the side of the device chip can be solved. Brief explanation of the drawing

[0016] FIG. 1 is a perspective view illustrating the process of arranging protective members. FIG. 2(a) is a perspective view of a case in which a modified layer is formed in a process of forming a splitting point, FIG. 2(b) is a cross-sectional view of a wafer in which a modified layer is formed along a planned splitting line, and FIG. 2(c) is a perspective view of a wafer in which a modified layer is formed along a planned splitting line. FIG. 3 is a perspective view of a case in which a groove with a depth corresponding to the finishing thickness of the device chip is formed by ablation processing in the process of forming a split point. FIG. 4 is a perspective view of a case in which a groove with a depth corresponding to the finishing thickness of a device chip is formed by cutting in a process of forming a split point. FIG. 5(a) is a perspective view illustrating a state in which a protective member is placed on the surface of a wafer in which a groove of a depth corresponding to the finishing thickness of the device chip is formed along a line scheduled for division, and FIG. 5(b) is a cross-sectional view illustrating a state in which the protective member is placed on the surface of the wafer shown in FIG. 5(a). FIG. 6(a) is a perspective view illustrating a backside grinding process, and FIG. 6(b) is a perspective view of a wafer with a split groove formed therein. FIG. 7(a) is a perspective view illustrating a state in which a stretchable sheet is placed on the back side of a wafer in a sheet placement process, and FIG. 7(b) is a perspective view illustrating a state in which a protective member is removed from the surface of a wafer in a sheet placement process. FIG. 8(a) is a perspective view illustrating an adhesive coating process, and FIG. 8(b) is a cross-sectional view of a wafer coated with adhesive. Figure 9 is a cross-sectional view illustrating the sheet stretching process. Figure 10 is a cross-sectional view illustrating a cleaning process. Specific details for implementing the invention

[0017] Hereinafter, a suitable embodiment of the wafer processing method of the present invention will be described with reference to the drawings.

[0018] FIG. 1 illustrates a wafer (2) in the shape of a disc, which is processed by the wafer processing method of the present invention. The wafer (2) may be formed from a suitable semiconductor material, such as silicon, for example. The surface (2a) of the wafer (2) is divided into a plurality of rectangular regions by a grid-shaped planned division line (4), and a device (6), such as an IC or LSI, is formed in each of the plurality of rectangular regions.

[0019] (Protection component placement process)

[0020] In this embodiment, first, a protective member placement process is performed to place a protective member (8) that protects the surface (2a) of the wafer (2), as shown in FIG. 1. As the protective member (8), a circular adhesive tape having a diameter approximately equal to the diameter of the wafer (2) may be used. Then, the protective member (8) is attached and placed on the surface (2a) of the wafer (2).

[0021] (Splitting point formation process)

[0022] In this embodiment, after performing the protective member placement process, a division starting point formation process is performed to form a division starting point on the planned division line (4).

[0023] The process of forming a split point can be performed, for example, using a laser processing device (10) shown in FIG. 2(a). The laser processing device (10) comprises a chuck table (12) that holds a wafer (2) in the suction, a laser oscillator (not shown) that emits a pulsed laser beam (LB) of a wavelength that is permeable to the wafer (2), a condenser (14) that concentrates the pulsed laser beam (LB) emitted by the laser oscillator and irradiates the wafer (2) held in the suction table (12), and an imaging unit (not shown) that captures the wafer (2) held in the suction table (12).

[0024] The chuck table (12) is configured to be rotatable about an axis extending in the vertical direction and is configured to be movable in the X-axis direction indicated by the arrow (X) in FIG. 2(a) and in the Y-axis direction orthogonal to the X-axis direction (direction indicated by the arrow (Y) in FIG. 2(a)). In addition, the XY plane defined by the X-axis direction and the Y-axis direction is substantially horizontal.

[0025] The imaging unit includes a conventional imaging element (CCD) that images a wafer (2) by visible light, an infrared irradiation means that irradiates infrared light that passes through the wafer (2), an optical system that captures infrared light irradiated by the infrared irradiation means, and an imaging element (infrared CCD) that outputs an electrical signal corresponding to the infrared light captured by the optical system.

[0026] Referring to FIG. 2(a), the explanation continues in the process of forming a split point. First, the back side (2b) of the wafer (2) is oriented upward, and the wafer (2) is held in place on the upper surface of the chuck table (12). Next, infrared rays are irradiated from an imaging unit, and the surface (2a) side of the wafer (2) is captured by the infrared rays transmitted from the back side (2b) of the wafer (2). Based on the image of the wafer (2) captured by the imaging unit, a split line (4) extending in a first direction is aligned with the X-axis direction. Additionally, a laser beam (LB) is aimed at the split line (4) aligned with the X-axis direction, and the point of focus of the laser beam (LB) is positioned inside the split line (4).

[0027] Next, while processing and moving the chuck table (12) in the X-axis direction, a laser beam (LB) of a wavelength that is permeable to the wafer (2) is irradiated onto the wafer (2) from a condenser (14) to form a modified layer (16) that serves as a starting point for division inside the wafer (2) along the planned division line (4), as shown in FIG. 2(a) and FIG. 2(b). In addition, from the perspective of preventing a decrease in the bending strength of the device chip, it is preferable to form the modified layer (16) to a depth that can be removed when grinding the back surface (2b) of the wafer (2) in the back surface grinding process described later.

[0028] Next, the chuck table (12) is indexed and moved in the Y-axis direction relative to the condenser (14) by the interval in the Y-axis direction of the planned division line (4). Then, by alternately repeating the irradiation of the laser beam (LB) and the indexing and moving, a modified layer (16) is formed inside the wafer (2) along the entire planned division line (4) extending in the first direction.

[0029] Then, by rotating the chuck table (12) 90 degrees and alternately repeating the irradiation of the laser beam (LB) and indexing transfer, a modified layer (16) is formed inside the wafer (2) along the entire length of the planned division line (4) extending in a second direction orthogonal to the planned division line (4) where the modified layer (16) was formed first. In this way, the process of forming the division starting point is carried out, and a grid-shaped modified layer (16) is formed inside the wafer (2) along the grid-shaped planned division line (4), as shown in FIG. 2(c).

[0030] This process of forming a split point can be carried out, for example, under the following processing conditions.

[0031] Wavelength of pulsed laser beam: 1342nm

[0032] Average output: 1.0W

[0033] Repeat frequency: 90kHz

[0034] Feed rate: 700 mm / s

[0035] In addition, in the above description, a modified layer (16) is formed by irradiating a laser beam (LB) from the back side (2b) of the wafer (2), but a modified layer (16) may also be formed by irradiating a laser beam (LB) from the surface side (2a) of the wafer (2), and in this case, a protective member placement process is performed after the process of forming the split point.

[0036] In this embodiment, although an example of forming a modified layer (16) as a starting point for division has been described, a groove with a depth corresponding to the finishing thickness of the device chip may be formed on the surface (2a) side of the wafer (2) along the planned division line (4) to serve as a starting point for division. Such a groove may be formed by ablation processing by irradiation with a laser beam or by cutting processing using a dicing device.

[0037] (Ablation processing)

[0038] Referring to FIG. 3, in the case of ablation processing, before placing a protective member (8) on the surface (2a) of the wafer (2), the wafer (2) is held in place by suction with the surface (2a) facing upward. Subsequently, a planned division line (4) extending in the first direction is aligned with the X-axis direction, and a laser beam (LB') of a wavelength that is absorbent to the wafer (2) is aimed at the planned division line (4). Additionally, the point of focus of the laser beam (LB') is positioned on the surface (2a).

[0039] Then, by processing and moving the chuck table (12) in the X-axis direction and irradiating the wafer (2) with a laser beam (LB'), a laser processing groove (18) with a depth corresponding to the finishing thickness of the device chip can be formed on the surface (2a) along the planned division line (4). In addition, similar to the case of forming the modified layer (16), the irradiation of the laser beam (LB') and indexing movement are repeated alternately to form a grid-shaped laser processing groove (18) on the surface (2a) along the planned division line (4).

[0040] When the starting point of the division is the laser processing groove (18), the process of forming the starting point of the division can be carried out under the following processing conditions, for example.

[0041] Laser beam wavelength: 355nm

[0042] Average output: 2.0W

[0043] Repeat frequency: 80kHz

[0044] Feed rate: 300 mm / s

[0045] (Cutting process)

[0046] When forming a groove by cutting, for example, a dicing device (20) as shown in FIG. 4 may be used. The dicing device (20) comprises a chuck table (22) that sucks and holds a wafer (2) and a cutting unit (24) that cuts the wafer (2) sucked and held by the chuck table (22). The cutting unit (24) includes a spindle (26) configured to rotate with the Y-axis direction as the axis and an annular cutting blade (28) fixed to the tip of the spindle (26).

[0047] In the case of cutting process, before placing the protective member (8) on the surface (2a) of the wafer (2), the wafer (2) is held in place on the upper surface of the chuck table (22) by having the surface (2a) face upward. Subsequently, the cutting edge of the cutting blade (28), which is rotated at high speed, is cut into the cutting line (4) aligned with the X-axis direction to a depth corresponding to the finishing thickness of the device chip from the surface (2a), while supplying cutting fluid to the part where the cutting edge of the cutting blade (28) is cut, and the chuck table (22) is processed and moved in the X-axis direction.

[0048] By doing so, a cutting groove (30) of a depth corresponding to the finishing thickness of the device chip can be formed along the planned division line (4). When performing cutting processing, the formation of the cutting groove (30) and indexing transfer are repeated alternately to form a grid-shaped cutting groove (30) on the surface (2a) along the grid-shaped planned division line (4).

[0049] When the starting point of the division is the cutting groove (30), for example, the process of forming the starting point of the division can be carried out under the following processing conditions.

[0050] Cutting blade diameter: φ50mm

[0051] Cutting blade rotation speed: 30,000 rpm

[0052] Cutting fluid supply: 2 liters / min

[0053] Feed rate: 50 mm / s

[0054] Since the groove (18, 30) as the starting point for division is formed on the surface (2a) side of the wafer (2), when forming the groove (18, 30) as the starting point for division, the process of forming the starting point for division is performed, as shown in FIG. 5(a) and FIG. 5(b), and then the process of placing the protective member is performed.

[0055] (Back grinding process)

[0056] If the protective member placement process and the division point formation process have been performed, the protective member (8) side is held on the chuck table and the back side (2b) of the wafer (2) is ground to finish to a desired thickness, and a division groove is formed in the division planned line (4) to divide the wafer (2) into individual device chips, and a back side grinding process is performed.

[0057] The backside grinding process can be performed, for example, using a grinding device (32) shown in FIG. 6(a). The grinding device (32) comprises a chuck table (34) that holds a wafer (2) and a grinding unit (36) that grinds the wafer (2) held by the chuck table (34).

[0058] The grinding unit (36) includes a spindle (38) extending in the vertical direction and a disc-shaped wheel mount (40) fixed to the bottom of the spindle (38). An annular grinding wheel (44) is fastened to the lower surface of the wheel mount (40) by means of a bolt (42). A plurality of grinding stones (46) arranged annularly at spaced intervals in the circumferential direction are fixed to the outer edge portion of the lower surface of the grinding wheel (44).

[0059] In the backside grinding process, first, the backside (2b) of the wafer (2) is oriented upward, and the wafer (2) is held in place on the upper surface of the chuck table (34). Next, the spindle (38) is rotated at a predetermined rotational speed (e.g., 6000 rpm) in the direction indicated by the arrow (R1) in FIG. 6(a). Additionally, the chuck table (34) is rotated at a predetermined rotational speed (e.g., 300 rpm) in the direction indicated by the arrow (R2).

[0060] Next, the spindle (38) is lowered to bring the grinding wheel (46) into contact with the back surface (2b) of the wafer (2), and grinding water is supplied to the part where the grinding wheel (46) is in contact with the back surface (2b). Then, by lowering the spindle (38) at a predetermined grinding feed rate (e.g., 1.0 μm / s), the back surface (2b) of the wafer (2) is ground, and the wafer (2) is thinned to the finishing thickness of the device chip.

[0061] When a modified layer (16) is formed as a starting point for division, cracks extend from the modified layer (16) in the thickness direction of the wafer (2) due to the pressure applied when the wafer (2) is being ground, and the wafer (2) is divided into individual device chips (50) as shown in FIG. 6(b). In addition, because a division groove (48) (a groove extending from the surface (2a) to the back surface (2b)) is formed by the cracks extending from the modified layer (16), the side of the device chip (50) becomes a cleavage surface.

[0062] Meanwhile, in the case where a laser processing groove (18) or a cutting groove (30) is formed as a starting point for division, since the depth of these grooves (18, 30) is a depth corresponding to the finishing thickness of the device chip (50), the grooves (18, 30) appear on the back surface (2b) of the wafer (2) and form a division groove (48) by grinding the back surface (2b) of the wafer (2) until the thickness is reached. By doing so, the wafer (2) is divided into individual device chips (50).

[0063] (Sheet placement process)

[0064] After performing a backside grinding process, a sheet placement process is performed to remove a protective member (8) from the surface (2a) of the wafer (2) while placing a stretchable sheet on the backside (2b) of the wafer (2).

[0065] In the sheet placement process, as shown in FIG. 7(a), a wafer (2) is placed on a circular sheet (54) whose periphery edge is fixed to an annular frame (52). As the sheet (54), a stretchable adhesive tape (e.g., an adhesive tape made of vinyl chloride) may be used. In this case, the back side (2b) of the wafer (2) is attached to the adhesive surface of the sheet (54). Additionally, if the sheet (54) is placed on the back side (2b), the protective member (8) is removed from the surface (2a) as shown in FIG. 7(b).

[0066] (Adhesive coating process)

[0067] After performing the sheet placement process, an adhesive coating process is performed to coat the surface (2a) of the wafer (2) with a fluid adhesive.

[0068] Referring to FIG. 8(a), in the adhesive coating process, the surface (2a) of the wafer (2) is oriented upward, and a fluid adhesive liquid (56) is applied to the center of the surface (2a). In order to easily remove the adhesive liquid (56) from the wafer (2) in the cleaning process described later, it is preferable to use a water-soluble resin as the adhesive liquid (56). Examples of water-soluble resins that can be used as the adhesive liquid (56) include polyvinyl alcohol, polyethylene oxide, polyacrylamide, carboxymethylcellulose, resol-type phenolic resin, methylolated urea resin, or methylolated melamine resin.

[0069] If adhesive liquid (56) is applied to the center of the surface (2a) of the wafer (2), the wafer (2) is rotated in the direction indicated by the arrow (R3) to cause the adhesive liquid (56) to flow by centrifugal force. By doing so, as shown in FIG. 8(b), the adhesive liquid (56) can be coated on the surface (2a) with a nearly uniform thickness.

[0070] (Sheet stretching process)

[0071] After performing the adhesive coating process, a sheet stretching process is performed to stretch the sheet (54) placed in the sheet placement process so that the width of the split groove (48) is expanded to allow the adhesive (56) to penetrate into the split groove (48), and the width of the split groove (48) is reduced to discharge the adhesive (56) from the split groove (48).

[0072] The sheet expansion process can be carried out, for example, using an expansion device (58) illustrated in FIG. 9. The expansion device (58) includes a cylindrical drum (60), an annular retaining member (62) disposed on the outer circumference of the drum (60), and a plurality of air cylinders (64) for raising and lowering the retaining member (62). A plurality of clamps (66) are disposed on the outer edge of the retaining member (62) at intervals in the circumferential direction.

[0073] In the sheet stretching process, first, the wafer (2) with the split groove (48) formed thereon is oriented upward, and the frame (52) is placed on the upper surface of the retaining member (62). Next, the frame (52) is secured with a plurality of clamps (66). Next, the retaining member (62) is lowered by a plurality of air cylinders (64) to apply radial tension to the sheet (54). When this is done, as indicated by the two-dot dashed line in FIG. 9, the width of the split groove (48) is expanded, and the adhesive liquid (56) penetrates into the split groove (48).

[0074] Next, the retaining member (62) is raised by a plurality of air cylinders (64) to release the radial tension applied to the sheet (54), and the width of the split groove (48) is reduced, thereby discharging the adhesive liquid (56) from the split groove (48). In this way, by performing the expansion and reduction of the width of the split groove (48) multiple times and repeating the intrusion of the adhesive liquid (56) into the split groove (48) and the discharge of the adhesive liquid (56) from the split groove (48), the processing debris attached to the side of the device chip (50) can be captured by the adhesive liquid (56).

[0075] (Cleaning process)

[0076] After performing the sheet stretching process, the adhesive liquid (56) is removed from the surface (2a) of the wafer (2) and a cleaning process is performed to clean at least the side of the split groove (48).

[0077] In the cleaning process, as shown in FIG. 10, cleaning water (68) is supplied from above toward the wafer (2) (device chip (50)) while the width of the split groove (48) is expanded by the expansion device (58). By doing so, processing debris can be removed along with the adhesive liquid (56) from the surface and sides of the device chip (50).

[0078] As described above, in the wafer processing method of the present embodiment, the processing debris attached to the side of the device chip (50) is captured by the fluid adhesive liquid (56), and then the side of the split groove (48) is cleaned, thereby removing the processing debris from the side of the device chip (50) together with the adhesive liquid (56).

[0079] Therefore, in subsequent processes such as wire bonding, die bonding, and stacking of device chips (50), the problem of processing debris falling and scattering from the side of the device chip (50) interfering with the bonding and adhering to the surface of the device chip (50) to damage the stacked device chip (50) can be resolved. Explanation of the symbols

[0080] 2: Wafer 2a: Surface of the wafer 2b: Backside of the wafer 4: Line scheduled for division 6: Device 8: Absence of protection 16: Modified layer (starting point of division) 18: Laser-processed groove (starting point of division) 30: Cutting groove (starting point of division) 48: Split Home 50: Device chip 54: Sheet 56: Adhesive 68: Washing water

Claims

Claim 1 A method for processing a wafer, wherein the wafer formed on the surface is partitioned by a plurality of planned division lines where a plurality of devices intersect, and the wafer is divided into individual device chips, comprising: a division starting point forming process for forming a division starting point on the planned division lines; a protective member placement process for placing a protective member that protects the surface of the wafer before or after the division starting point forming process; a backside grinding process for maintaining the side of the protective member on a chuck table and grinding the backside of the wafer to finish it to a desired thickness, while simultaneously forming a division groove on the planned division lines to divide the wafer into individual device chips; a sheet placement process for placing a stretchable sheet on the backside of the wafer and simultaneously removing the protective member from the surface of the wafer; an adhesive coating process for coating a fluid adhesive on the surface of the wafer; a sheet stretching process for stretching the sheet placed in the sheet placement process to expand the width of the division groove to allow the adhesive to penetrate the division groove, while simultaneously reducing the width of the division groove to discharge the adhesive from the division groove; and removing the adhesive from the surface of the wafer so as to at least the division groove A method for processing a wafer, comprising a cleaning process for cleaning the sides. Claim 2 A method for processing a wafer according to claim 1, wherein, in the process of forming the division point, a point of concentration of a laser beam of a wavelength that is permeable to the wafer is positioned inside the wafer corresponding to the line to be divided, and the laser beam is irradiated onto the wafer to form a modified layer that serves as the division point. Claim 3 A wafer processing method according to claim 1, wherein in the process of forming the division point, a groove having a depth corresponding to the finishing thickness of the device chip is formed in the line scheduled for division to serve as the division point. Claim 4 In paragraph 3, the above protective member placement process is a wafer processing method performed after the above division point formation process. Claim 5 A method for processing a wafer according to claim 1, wherein the adhesive used in the adhesive coating process is selected from the group consisting of polyvinyl alcohol, polyethylene oxide, polyacrylamide, carboxymethylcellulose, resol-type phenolic resin, methylolated urea resin, and methylolated melamine resin, and wherein, in the cleaning process, cleaning water is supplied to remove the adhesive.

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