JP5860216B2 - Wafer chamfer removal method - Google Patents

Description

  The present invention provides a device region in which a plurality of streets are formed in a lattice pattern on the surface and a device is formed in a plurality of regions partitioned by the plurality of streets, and a peripheral surplus that surrounds the device region and has a chamfered portion on the outer periphery. The present invention relates to a method for removing a chamfered portion of a wafer having a region.

  In a semiconductor device manufacturing process, a plurality of streets called streets arranged in a grid pattern are formed in a grid pattern on the surface of a substantially disk-shaped semiconductor wafer, and devices such as ICs and LSIs are formed in the partitioned areas. Form. Then, the semiconductor wafer is cut along the streets to divide the region in which the device is formed to manufacture individual semiconductor devices.

  In order to reduce the size and weight of semiconductor devices, the semiconductor wafer is ground to the predetermined thickness by grinding the backside of the semiconductor wafer prior to cutting the semiconductor wafer along the street and dividing it into individual devices. Yes.

  However, in the semiconductor wafer, in order to prevent cracking and dust generation during the process of forming the semiconductor device, an arc-shaped chamfer is formed on the outer peripheral portion of the outer peripheral region surrounding the device region where the device is formed. . If the back surface of a semiconductor wafer having an arcuate chamfered shape such as 600 μm is ground and finished to a thickness of 100 μm, a so-called knife edge is formed on the outer periphery of the semiconductor wafer, which is dangerous. There is a problem that chipping occurs from the outer periphery and the semiconductor wafer is damaged.

  In order to solve the above-described problem, before the back surface of the semiconductor wafer is ground to a predetermined thickness, the chamfered portion is removed by cutting with a cutting blade from the front surface side of the semiconductor wafer, and then the back surface of the semiconductor wafer is removed. A technique of grinding to form a predetermined thickness is disclosed in Patent Document 1 below.

  In addition, in order to solve the above-mentioned problems, the semiconductor wafer is supported by a protective tape or a substrate before the back surface of the semiconductor wafer is ground to a predetermined thickness, and the chamfer formed on the outer periphery of the semiconductor wafer is formed. A method of removing the portion by grinding with a grinding wheel is disclosed in Patent Document 2 below.

JP 2007-158239 A JP 2000-173961 A

When the chamfered portion is cut and removed from the front surface side of the wafer by a cutting blade as described in Patent Document 1, there is a problem that the cutting surface adheres to the surface of the wafer and the device surface is contaminated.
When the protective tape is attached to the surface of the wafer and the chamfered portion is completely cut with a cutting blade from the back side of the wafer while the protective tape side is held on the chuck table of the cutting device, the annular chamfered portion becomes the protective tape. There is a problem that if the wafer remains in the stuck state and the back surface of the wafer is ground in this state, grinding scraps enter the annular cutting groove and contaminate the outer periphery of the wafer.
Further, as described in Patent Document 2, the method of removing the chamfered portion formed on the outer peripheral portion of the wafer by grinding with a grinding wheel does not cause chipping on the outer periphery of the wafer from which the chamfered portion has been removed by grinding. In addition, it is necessary to use a finishing grinding wheel composed of abrasive grains having a small particle size (for example, about 2 μm). For this reason, the method of grinding and removing the chamfered portion formed on the outer peripheral portion of the wafer with a grinding wheel requires a considerable amount of time as compared with the above-described cutting with the cutting blade, and has a problem that productivity is extremely poor. is there.

  The present invention has been made in view of the above-mentioned facts, and the main technical problem thereof is a wafer that can efficiently remove the chamfered portion formed on the outer peripheral portion without contaminating the device surface or outer periphery of the wafer. It is in providing the chamfer part removal method of this.

In order to solve the above main technical problem, according to the present invention, a device region in which a plurality of streets are formed in a lattice shape on the surface and a device is formed in a plurality of regions partitioned by the plurality of streets, and the device region A method for removing a chamfered portion of a wafer having an outer peripheral surplus region having a chamfered portion on the outer periphery,
A protective member attaching step for attaching a protective member to the surface of the wafer;
A wafer holding step for holding the protective member side adhered to the wafer surface on the holding surface of the rotatable chuck table;
While rotating the chuck table, the protective member is positioned at the boundary portion of the chamfered portion in the outer peripheral surplus region while rotating the cutting blade mounted on the rotary spindle arranged on the straight line orthogonal to the rotation center of the chuck table A chamfered portion cutting step of cutting the chamfered portion with a cutting depth reaching
While rotating the chuck table, the grinding wheel mounted on the rotary spindle arranged on the straight line orthogonal to the rotation center of the chuck table is rotated and the cutting surface of the outer peripheral surplus area where the chamfered portion is cut is not contacted. Chamfered portion grinding step of positioning and removing the chamfered portion cut from the protective member by positioning at the chamfered portion cut at
A method for removing a chamfered portion of a wafer is provided.

  The chamfered portion grinding process is started when the chamfered portion cutting step is performed and the cutting start position of the chamfered portion reaches the grinding wheel.

Further, according to the present invention, a plurality of streets are formed in a lattice shape on the surface, and a device region is formed in a plurality of regions partitioned by the plurality of streets, and the device region is surrounded by a chamfered portion on the outer periphery. A chamfered portion removing method for a wafer having an outer peripheral surplus area comprising:
A protective member attaching step for attaching a protective member to the surface of the wafer;
A wafer holding step for holding the protective member side adhered to the wafer surface on the holding surface of the rotatable chuck table;
While rotating the chuck table, the protective member is positioned at the boundary portion of the chamfered portion in the outer peripheral surplus region while rotating the cutting blade mounted on the rotary spindle arranged on the straight line orthogonal to the rotation center of the chuck table A chamfered portion cutting step of cutting the chamfered portion with a cutting depth reaching
While rotating the chuck table, the grinding wheel mounted on the rotary spindle arranged on a straight line orthogonal to the rotation center of the chuck table is rotated, and the chamfered portion is positioned at the boundary portion of the chamfered portion in the outer peripheral surplus region. Chamfered portion grinding process to be removed by grinding,
The chamfered portion cutting step and the chamfered portion grinding step are performed simultaneously.
A method for removing a chamfered portion of a wafer is provided.

  It is desirable to increase the rotation speed of the chuck table when the chamfered portion grinding start position reaches the cutting blade by performing the chamfered portion grinding step.

  In the method for removing a chamfered portion of a wafer according to the present invention, a protective member is attached to the surface of the wafer, and the chamfered portion cutting step and the cut chamfered portion are ground while the protective member side is held on the chuck table. Since the chamfered portion grinding step to be removed is performed, the wafer surface is not contaminated. In addition, the outer periphery of the wafer is finished by cutting with the cutting blade, and the grinding wheel grinds the chamfered portion that is cut without contact with the cut surface finished by cutting with the cutting blade, so that the outer periphery of the wafer is chipped. The chamfered portion can be efficiently removed without any trouble. Further, in the method for removing a chamfered portion of a wafer according to the present invention, since the chamfered portion cut by the cutting blade is completely removed by performing the chamfered portion grinding step, the back surface of the wafer to be performed thereafter is ground. Thus, in the back grinding process of forming a predetermined thickness, the outer peripheral surface of the wafer is not contaminated by grinding debris.

The perspective view of the semiconductor wafer as a wafer processed by the chamfer part removal method of the wafer by the present invention. Sectional drawing which expands and shows the semiconductor wafer shown in FIG. Explanatory drawing of the protection member sticking process in the chamfer part removal method of the wafer by this invention. The principal part perspective view of the processing apparatus for implementing the chamfer part cutting process and the chamfer part grinding process in the chamfer part removal method of the wafer by this invention. Explanatory drawing of the wafer holding process in the chamfer part removal method of the wafer by this invention. Explanatory drawing of the chamfer part cutting process in the chamfer part removal method of the wafer by this invention. Explanatory drawing of the chamfer part cutting process and the chamfer part grinding process in the chamfer part removal method of the wafer by this invention. Explanatory drawing which shows other embodiment of the chamfer part cutting process and the chamfer part grinding process in the chamfer part removal method of the wafer by this invention.

  Preferred embodiments of a method for removing a chamfered portion of a wafer according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view of a semiconductor wafer 2 as a wafer to be processed by the method for removing a chamfered portion of a wafer according to the present invention. A semiconductor wafer 2 shown in FIG. 1 is made of, for example, a disk-shaped silicon wafer having a thickness of 600 μm, and a plurality of streets 21 are arranged in a lattice pattern on the surface 2a. Devices 22 such as ICs and LSIs are formed in the plurality of regions. The semiconductor wafer 2 configured as described above includes a device region 220 in which the device 22 is formed, and an outer peripheral surplus region 230 surrounding the device region 220. In the outer peripheral portion of the outer peripheral surplus region 230, As shown in FIG. 2, an arc-shaped chamfered portion 2c formed symmetrically from the front surface 2a to the back surface 2b is formed.

A method for removing the chamfered portion of the wafer for removing the arc-shaped chamfered portion 2c formed on the outer peripheral portion of the semiconductor wafer 2 shown in FIGS. 1 and 2 will be described below.
In the method for removing a chamfered portion of a wafer according to the present invention, first, in order to protect the device 22 formed on the surface 2a of the semiconductor wafer 2, the surface of the semiconductor wafer 2 as shown in FIGS. 3 (a) and 3 (b). A protective member T such as a protective tape is attached to 2a (protective member attaching step).

  If the protective member sticking step described above is performed, a chamfered portion cutting step for cutting the chamfered portion 2c of the semiconductor wafer 2 and a chamfered portion grinding step for grinding and removing the cut chamfered portion are performed. The chamfered portion cutting step and the chamfered portion grinding step are performed by the processing apparatus shown in FIG. 4 includes a chuck table 31 that holds a workpiece, a cutting means 32 that cuts the workpiece held on the chuck table 31, and a workpiece that is held on the chuck table 31. Grinding means 33 is provided. The chuck table 31 includes a chuck table main body 311 and an adsorption chuck 312 that is disposed on the upper surface of the chuck table main body 311 and is formed of a porous ceramic material. The chuck table 31 configured in this manner is configured to suck and hold the workpiece on the holding surface which is the upper surface of the suction chuck 312 and is configured to be rotated by a rotation mechanism (not shown).

The cutting means 32 includes a spindle housing 321 arranged substantially horizontally, and a straight line orthogonal to the rotation center of the chuck table 31 supported by the spindle housing 321 so as to be rotatable in parallel with the holding surface which is the upper surface of the chuck table 31. The rotary spindle 322 disposed above and a cutting blade 323 mounted on the tip of the rotary spindle 322 are rotated by a servo motor (not shown) disposed in the spindle housing 321. It is supposed to be. In the illustrated embodiment, the cutting blade 323 is composed of an electroformed blade having a thickness of 20 to 30 μm in which diamond abrasive grains having a particle diameter of 1 to 2 μm are bonded by metal plating such as nickel.

The grinding means 33 includes a spindle housing 331 arranged substantially horizontally, and a straight line orthogonal to the rotation center of the chuck table 31 supported by the spindle housing 331 so as to be rotatable in parallel with a holding surface which is the upper surface of the chuck table 31. A rotary spindle 332 disposed on the cutting means 32 so as to face the rotary spindle 322 and a disc-shaped grinding wheel 333 mounted on the tip of the rotary spindle 332 are included. The rotary spindle 332 is a spindle. It can be rotated by a servo motor (not shown) disposed in the housing 331. In the illustrated embodiment, the grinding wheel 333 is a resinoid grindstone in which diamond abrasive grains having a particle size of 30 to 40 μm are kneaded into a resin bond material, molded into a ring shape, and fired, or abrasive grains are mixed into a metal bond material. It consists of a metal grindstone that has been tempered, molded into an annular shape and fired, and has a thickness of about 1 mm.

  To perform the chamfered portion cutting step of cutting the chamfered portion 2c of the semiconductor wafer 2 and the chamfered portion grinding step of grinding and removing the cut chamfered portion using the processing apparatus 3 described above, as shown in FIG. The protective member T side of the semiconductor wafer 2 having the protective member T attached to the surface thereof by the protective member attaching step is placed on the holding surface which is the upper surface of the suction chuck 312 constituting the chuck table 31. Then, by operating a suction means (not shown), the conductor wafer 2 is sucked and held on the chuck table 31 via the protective member T (wafer holding step). Therefore, the back surface 2b of the semiconductor wafer 2 sucked and held on the chuck table 31 is on the upper side.

  When the wafer holding step described above is performed, the cutting blade 323 mounted on the rotary spindle 322 of the cutting means 32 is moved in the direction indicated by the arrow 323a (clockwise as viewed from the front) as shown in FIG. For example, it is positioned at the boundary portion of the circular chamfered portion 2c in the outer peripheral surplus region 230 of the semiconductor wafer 2 sucked and held on the chuck table 31 while rotating at a rotation speed of 20000 rpm. Then, the cutting blade 323 is cut and fed downward in FIG. 6A to be positioned at a predetermined cutting feed position where the outer peripheral edge of the cutting blade 323 reaches the protection member T. When the cutting blade 323 is thus positioned at the predetermined cutting feed position, the chuck table 31 is rotated in the direction indicated by the arrow 31a (clockwise as viewed from the front) at a rotational speed of, for example, 2 degrees / second. As a result, as shown in FIG. 6B, the boundary portion of the arc-shaped chamfered portion 2c in the outer peripheral surplus region 230 of the semiconductor wafer 2 is cut by the cutting groove 240 cut by the cutting blade 323 (cutting the chamfered portion). Process). In the chamfered portion cutting step, processing water that is pure water is supplied to the cutting portion by the cutting blade 323.

  The chamfered portion cutting step described above is started, and the cutting start position of the chamfered portion indicated by the arrow 240a in FIG. 6B reaches the grinding region by the disc-shaped grinding wheel 333 mounted on the rotary spindle 332 of the grinding means 33. Then, as shown in FIG. 7A, the grinding wheel 333 is rotated in the direction indicated by the arrow 333a (counterclockwise when viewed from the front) at a rotational speed of, for example, 20000 rpm, as shown in FIG. Then, the outer peripheral edge of the grinding wheel 333 is positioned at a predetermined grinding feed position where the protective member T is reached. At this time, the grinding wheel 333 is positioned in a state where the side surface on the center side of the chuck table 31 does not contact the cut surface of the outer peripheral surplus region 230. As a result, as shown in FIG. 7B, the chamfered portion 2c cut by the cutting blade 323 as described above is ground by the outer peripheral surface of the grinding wheel 333 and removed from the protective member T (chamfered portion grinding step). ). By carrying out this chamfered portion grinding process until the chamfered portion 2c cut by the cutting blade 323 passes through the grinding wheel 333, as shown in FIG. 7C, an arc shape in the outer peripheral surplus region 230 of the semiconductor wafer 2 is obtained. The chamfered portion 2c can be completely removed, and the outer peripheral portion of the protective member T is exposed. In the chamfered portion grinding step, pure water that is pure water is supplied to the grinding portion by the grinding wheel 333.

  As described above, in the illustrated embodiment, the chamfered portion cutting step is performed in a state where the protective member T is adhered to the surface of the semiconductor wafer 2 and the protective member T side is held on the chuck table 31 of the processing apparatus 3. Since the chamfered portion grinding step of grinding and removing the cut chamfered portion is performed, the surface of the semiconductor wafer 2 is not contaminated. In the illustrated embodiment, the outer periphery of the semiconductor wafer 2 is finished by cutting with a cutting blade 323 formed of fine abrasive grains having a small particle size, and a grinding wheel 333 formed of abrasive grains having a large particle size and coarseness. Since the chamfered portion 2c cut without contacting the cut surface finished by cutting with the cutting blade 323 is ground, the chamfered portion can be efficiently removed without causing chipping in the outer periphery of the semiconductor wafer 2. .

  If the arc-shaped chamfered portion 2c in the outer peripheral surplus region 230 of the semiconductor wafer 2 is removed as described above, the back surface grinding apparatus that grinds the back surface of the semiconductor wafer 2 with the protective tape T attached to the surface. It is conveyed to. And the semiconductor wafer 2 conveyed to the back surface grinding apparatus is formed with a predetermined thickness by grinding the back surface. When performing this back grinding process, the chamfered part 2c cut and separated by the cutting blade 323 as described above is completely removed by carrying out the chamfered part grinding process. The outer peripheral surface of the wafer 2 is not contaminated.

Next, another embodiment of the method for removing a chamfered portion of a wafer according to the present invention will be described with reference to FIG.
Also in the embodiment shown in FIG. 8, the protective member attaching step shown in FIG. 3 and the wafer holding step shown in FIG. 5 in the method for removing a chamfered portion of the wafer are performed. When the protective member attaching step shown in FIG. 3 and the wafer holding step shown in FIG. 5 are performed, the cutting blade 323 mounted on the rotary spindle 322 of the cutting means 32 is moved to an arrow 323a as shown in FIG. Is positioned at the boundary portion of the arc-shaped chamfered portion 2c in the outer peripheral surplus region 230 of the semiconductor wafer 2 sucked and held on the chuck table 31 while rotating at a rotational speed of 20000 rpm, for example, in the direction indicated by . Then, the cutting blade 323 is cut and fed downward in FIG. 8A to be positioned at a predetermined cutting feed position where the outer peripheral edge of the cutting blade 323 reaches the protective member T. Further, as shown in FIG. 8A, the disc-shaped grinding wheel 333 mounted on the rotary spindle 332 of the grinding means 33 is rotated at a rotational speed of, for example, 20000 rpm in the direction indicated by the arrow 333a (counterclockwise when viewed from the front). It is positioned at the boundary part of the arc-shaped chamfered part 2c in the outer peripheral surplus area 230 of the semiconductor wafer 2 that is sucked and held on the chuck table 31 while rotating. Then, the grinding wheel 333 is ground and fed downward in FIG. 8A to be positioned at a predetermined grinding feed position where the outer peripheral edge of the grinding wheel 333 reaches the protective member T. At this time, the grinding wheel 333 is positioned so that the side surface on the center side of the chuck table 31 corresponds to the cutting groove formed by the cutting blade 323.

  When the cutting blade 323 is thus positioned at the predetermined cutting feed position and the grinding wheel 333 is positioned at the predetermined grinding feed position, the chuck table 31 is moved in the direction indicated by the arrow 31a (clockwise as viewed from the front), for example. Rotate at a rotation speed of 2 degrees / second. As a result, as shown in FIG. 8B, the boundary portion of the arc-shaped chamfered portion 2c in the outer peripheral surplus region 230 of the semiconductor wafer 2 is cut by the cutting groove 240 cut by the cutting blade 323 (cutting the chamfered portion). In addition, the arc-shaped chamfered portion 2c in the outer peripheral surplus region 230 of the semiconductor wafer 2 is ground and removed by the grinding wheel 333 (chamfered portion grinding step). In the chamfered portion cutting step and the chamfered portion grinding step, pure water which is pure water is supplied to the cutting portion by the cutting blade 323 and the grinding portion by the grinding wheel 333.

  As described above, when the chamfered portion cutting step by the cutting blade 323 and the chamfered portion grinding step by the grinding wheel 333 are performed at the same time, one half region of the arc-shaped chamfered portion 2c in the outer peripheral surplus region 230 of the semiconductor wafer 2 is cut. The chamfered portion cutting step by the blade 323 is performed first, and the chamfered portion grinding step by the grinding wheel 333 is performed first in the other half region. Therefore, one half region of the arc-shaped chamfered portion 2 c in the outer peripheral surplus region 230 of the semiconductor wafer 2 is formed by the chamfered portion 2 c cut by the cutting groove 240 cut by the cutting blade 323 by the outer peripheral surface of the grinding wheel 333. It is ground and removed from the protective member T. At this time, since the grinding wheel 333 is positioned so that the side surface on the center side of the chuck table 31 corresponds to the cutting groove by the cutting blade 323, the grinding wheel 333 is cut by the cutting blade 323 in the same manner as in the above-described embodiment. Since there is no contact, the cutting surface by the cutting blade 323 formed by fine abrasive grains is not ground by the grinding wheel 333 formed by coarse abrasive grains. Accordingly, the cut surface of the outer peripheral surplus region 230 of the semiconductor wafer 2 is not chipped.

  On the other hand, the other half region of the arc-shaped chamfered portion 2 c in the outer peripheral surplus region 230 of the semiconductor wafer 2 is the outer peripheral surplus region 230 of the semiconductor wafer 2 in which the arc-shaped chamfered portion 2 c is ground and removed by the grinding wheel 333. The outer peripheral surface is modified like a polished surface by the cutting blade 323. That is, chipping occurs on the outer peripheral surface of the outer peripheral surplus region 230 of the semiconductor wafer 2 ground by the grinding wheel 333 formed of coarse abrasive grains, but this outer peripheral portion is positioned so that the cutting blade 323 acts slightly. Therefore, it is corrected like a polished surface by the action of the cutting blade 323 formed by fine abrasive grains. As described above, the chamfered portion cutting step by the cutting blade 323 and the chamfered portion grinding step by the grinding wheel 333 are simultaneously performed, so that the chuck table 31 holding the semiconductor wafer 2 is rotated once, so that (c) in FIG. ), The arc-shaped chamfered portion 2c in the outer peripheral surplus region 230 of the semiconductor wafer 2 can be removed, and the outer peripheral surface of the outer peripheral surplus region 230 is polished by a cutting blade 323 formed of fine abrasive grains. It will be in the state formed as follows.

  In the embodiment shown in FIG. 8, the rotation speed of the chuck table 31 is set at the time when the grinding start position indicated by the arrow 250a in FIG. Speed up to 3 degrees / second. That is, the cutting operation by the cutting blade 323 that corrects the outer peripheral surface of the outer peripheral surplus region 230 of the semiconductor wafer 2 ground by the grinding wheel 333 only causes the cutting blade 323 to act slightly on the outer peripheral surface of the outer peripheral surplus region 230. The semiconductor wafer 2 can be modified like a polished surface by the action of the cutting blade 323 formed by fine abrasive grains without taking a cutting time as in the chamfered portion cutting step for completely cutting the semiconductor wafer 2. Therefore, when the grinding start position 250a reaches the cutting blade 323, the processing time can be shortened by increasing the rotational speed of the chuck table 31 to, for example, a rotational speed of 3 degrees / second. On the other hand, the chamfered portion 2 c cut by the cutting blade 323 is ground by the grinding wheel 333 and removed from the protective member T, but the chamfered portion 2 c cut by the cutting blade 323 is completely separated from the semiconductor wafer 2. Even if the rotation speed of the chuck table 31 is increased and the grinding accuracy is rough, there is no influence on the processing accuracy of the outer peripheral surface of the outer peripheral surplus region 230 of the semiconductor wafer 2.

2: Semiconductor wafer 22: Device 220: Device region 230: Excess peripheral region 2c: Arc-shaped chamfered portion 3: Processing device 31: Chuck table 32: Cutting means 323: Cutting blade 33: Grinding means 333: Grinding wheel
T: Protection member

Claims (4)

A plurality of streets are formed in a lattice shape on the surface, and a device region in which devices are formed in a plurality of regions partitioned by the plurality of streets, and an outer peripheral surplus region surrounding the device region and having a chamfered portion on the outer periphery A method for removing a chamfered portion of a wafer,
A protective member attaching step for attaching a protective member to the surface of the wafer;
A wafer holding step for holding the protective member side adhered to the wafer surface on the holding surface of the rotatable chuck table;
While rotating the chuck table, the protective member is positioned at the boundary portion of the chamfered portion in the outer peripheral surplus region while rotating the cutting blade mounted on the rotary spindle arranged on the straight line orthogonal to the rotation center of the chuck table A chamfered portion cutting step of cutting the chamfered portion with a cutting depth reaching
While rotating the chuck table, the grinding wheel mounted on the rotary spindle arranged on the straight line orthogonal to the rotation center of the chuck table is rotated and the cutting surface of the outer peripheral surplus area where the chamfered portion is cut is not contacted. Chamfered portion grinding step of positioning and removing the chamfered portion cut from the protective member by positioning at the chamfered portion cut at
A method for removing a chamfered portion of a wafer.   The method for removing a chamfered portion of a wafer according to claim 1, wherein the chamfered portion grinding step is started when the chamfered portion cutting step is performed and the cutting start position of the chamfered portion reaches the grinding wheel. A plurality of streets are formed in a lattice shape on the surface, and a device region in which devices are formed in a plurality of regions partitioned by the plurality of streets, and an outer peripheral surplus region surrounding the device region and having a chamfered portion on the outer periphery A method for removing a chamfered portion of a wafer,
A protective member attaching step for attaching a protective member to the surface of the wafer;
A wafer holding step for holding the protective member side adhered to the wafer surface on the holding surface of the rotatable chuck table;
While rotating the chuck table, the protective member is positioned at the boundary portion of the chamfered portion in the outer peripheral surplus region while rotating the cutting blade mounted on the rotary spindle arranged on the straight line orthogonal to the rotation center of the chuck table A chamfered portion cutting step of cutting the chamfered portion with a cutting depth reaching
While rotating the chuck table, the grinding wheel mounted on the rotary spindle arranged on a straight line orthogonal to the rotation center of the chuck table is rotated, and the chamfered portion is positioned at the boundary portion of the chamfered portion in the outer peripheral surplus region. Chamfered portion grinding process to be removed by grinding,
The chamfered portion cutting step and the chamfered portion grinding step are performed simultaneously.
A method for removing a chamfered portion of a wafer.   4. The method for removing a chamfered portion of a wafer according to claim 3, wherein the chamfered portion grinding step increases the rotational speed of the chuck table when the grinding start position of the chamfered portion reaches the cutting blade.

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