JP2009050931A - Grinding wheel - Google Patents

Abstract

A grinding wheel capable of effectively grinding an annular portion of a workpiece is provided.
A grinding wheel 5 for grinding a workpiece mounted on a wheel mount 44 attached to a rotating spindle 42 of a grinding apparatus and held on a chuck table, and is attachable to and detachable from a lower surface of the wheel mount. A disc-shaped wheel base 51 having a mounting surface to be mounted and a grindstone mounting surface; a first grinding wheel 52 annularly disposed on the grindstone mounting surface of the wheel base around the center of rotation of the wheel base; The first grinding wheel 53 includes a second grinding wheel 53 that surrounds the first grinding wheel on the grinding wheel mounting surface of the wheel base and is annularly arranged around the center of rotation of the wheel base. It is configured to protrude in the axial direction from the grinding surface of the second grinding wheel.
[Selection] Figure 2

Description

  The present invention relates to a workpiece such as a semiconductor wafer, and more particularly to a grinding wheel for grinding an annular portion of the workpiece.

  In the semiconductor device manufacturing process, a plurality of regions are partitioned by dividing lines called streets arranged in a lattice pattern on the surface of a substantially wafer-shaped semiconductor wafer, and devices such as ICs, LSIs, etc. are partitioned in the partitioned regions. 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 addition, optical device wafers with gallium nitride compound semiconductors laminated on the surface of a sapphire substrate are also divided into individual optical devices such as light emitting diodes and laser diodes by cutting along the streets, and are widely used in electrical equipment. ing.

As described above, the wafer to be divided is formed to have a predetermined thickness by grinding or etching the back surface before cutting along the street. In recent years, it has been required to form a wafer with a thickness of 100 μm or less in order to reduce the weight and size of electrical equipment.
However, if the thickness of the wafer is formed to be 100 μm or less, the wafer is likely to be damaged, and it is difficult to handle the wafer.

In order to solve the above-described problem, the region corresponding to the device region on the back surface of the wafer is ground to form the thickness of the device region to a predetermined thickness, and the outer peripheral surplus region on the back surface of the wafer is left to remain in an annular shape. There has been proposed a wafer processing method capable of forming a rigid wafer by forming a reinforcing portion. (For example, refer to Patent Document 1.)
JP 2007-19461 A

  By the way, when the wafer described above is divided along the street, the annular reinforcing portion needs to be obstructed and removed. In order to remove the annular reinforcing portion, a cutting device including a chuck table for holding a workpiece and a cutting means having a cutting blade for cutting the workpiece held on the chuck table is used. Can be considered. That is, a rotating cutting blade is positioned at the boundary between the device region and the outer peripheral surplus region of the wafer held on the chuck table, and a predetermined cutting feed is applied to the cutting blade to perform cutting while rotating the chuck table.

  Thus, when the above-described cutting apparatus is used for cutting while rotating the chuck table holding the wafer, the cutting blade has a straight advance, so that when the cutting blade is cut into an arc, a large load acts on the cutting blade and the wafer. For this reason, there is a problem that not only the cutting blade is broken, but also the device region of the thinly formed wafer is damaged.

  The present invention has been made in view of the above facts, and the present inventor has considered that grinding is effective in order to remove the annular reinforcing portion without damaging the device region of the wafer. Therefore, the main technical problem of the present invention is to provide a grinding wheel capable of effectively grinding an annular portion of a workpiece.

In order to solve the above technical problem, according to the present invention, a grinding wheel for grinding a workpiece mounted on a wheel mount attached to a rotating spindle of a grinding apparatus and held on a chuck table,
A disc-shaped wheel base having a mounting surface detachably mounted on the lower surface of the wheel mount and a grindstone mounting surface formed on the opposite side of the mounting surface;
A first grinding wheel disposed in an annular shape around the center of rotation of the disk-shaped wheel base on the surface of the disk-shaped wheel base, and the wheel mounting of the disk-shaped wheel base A first grinding wheel surrounding the first grinding wheel, and a second grinding wheel disposed in an annular shape around the center of rotation of the disk-shaped wheel base,
The grinding surface of the first grinding wheel is configured to protrude in the axial direction from the grinding surface of the second grinding wheel.
A grinding wheel is provided.

  One of the first grinding wheel and the second grinding wheel is formed by a rough grinding wheel, and the other is formed by a finish grinding wheel.

  A grinding wheel according to the present invention includes a disc-shaped wheel base, a first grinding wheel disposed in an annular shape around the center of rotation of the disc-shaped wheel base on a grindstone mounting surface of the disc-shaped wheel base, And a second grinding wheel surrounding the first grinding wheel on the wheel mounting surface of the disk-shaped wheel base and annularly arranged around the center of rotation of the disk-shaped wheel base. Since the grinding surface of the grinding wheel protrudes in the axial direction from the grinding surface of the second grinding wheel, the annular portion of the workpiece is formed without interfering with each other by the first grinding wheel and the second grinding wheel. Can be ground.

Hereinafter, preferred embodiments of a grinding wheel according to the present invention will be described in more detail with reference to the accompanying drawings.
Here, a method of forming an annular reinforcing portion by grinding a region corresponding to the device region on the back surface of the wafer to form a thickness of the device region to a predetermined thickness and leaving an outer peripheral surplus region on the back surface of the wafer Will be described with reference to FIGS.
FIG. 6 is a perspective view of a semiconductor wafer as a wafer. A semiconductor wafer 100 shown in FIG. 6 is made of, for example, a silicon wafer having a thickness of 350 μm. A plurality of streets 101 are formed in a lattice shape on the surface 100a, and a plurality of streets partitioned by the plurality of streets 101 are formed. A device 102 such as an IC or LSI is formed in the region. The semiconductor wafer 100 configured as described above includes a device region 104 in which the device 102 is formed, and an outer peripheral surplus region 105 that surrounds the device region 104.

  When the semiconductor wafer 100 is cut along the street 101 and divided into individual devices, a region corresponding to the device region 104 on the back surface of the semiconductor wafer 100 is ground to form a thickness of the device region 104 to a predetermined thickness. At the same time, an annular reinforcing portion is formed in a region corresponding to the outer peripheral surplus region 105 on the back surface of the semiconductor wafer 100. In order to perform such processing, first, as shown in FIG. 7, the protective member 110 is attached to the surface 100 a of the semiconductor wafer 100 (protective member attaching step). Therefore, the back surface 100b of the semiconductor wafer 100 is exposed.

  When the protective member attaching step is performed, a region corresponding to the device region 104 on the back surface 100b of the semiconductor wafer 100 is ground to form a thickness of the device region 104 to a predetermined thickness, and the back surface 100b of the semiconductor wafer 100 is formed. The reinforcement part formation process which leaves the area | region corresponding to the outer periphery surplus area | region 105 in this, and forms a cyclic | annular reinforcement part is implemented. This reinforcement part formation process is implemented by the grinding apparatus shown in FIG.

  A grinding apparatus 1 shown in FIG. 8 includes a chuck table 11 that holds a wafer as a workpiece, and a grinding means 12 that grinds the processed surface of the wafer held on the chuck table 11. The chuck table 11 sucks and holds the wafer on its upper surface and is rotated in the direction indicated by the arrow 11a in FIG. The grinding means 12 includes a spindle housing 121, a rotary spindle 122 rotatably supported by the spindle housing 121 and rotated by a rotary drive mechanism (not shown), a mounter 123 attached to the lower end of the rotary spindle 122, and the mounter And a grinding wheel 124 attached to the lower surface of 123. The grinding wheel 124 is composed of a disk-shaped base 125 and a grinding wheel 126 arranged in an annular shape on a grindstone mounting surface that is the lower surface of the base 125, and a mounting surface that is the upper surface of the base 125. Is attached to the lower surface of the mounter 123.

  In order to perform the reinforcing portion forming step using the grinding apparatus 1 described above, the protective member 110 side of the semiconductor wafer 100 conveyed by the wafer carrying means (not shown) is placed on the upper surface (holding surface) of the chuck table 11. The semiconductor wafer 100 is sucked and held on the chuck table 11. Here, the relationship between the semiconductor wafer 100 held on the chuck table 11 and the annular grinding wheel 126 constituting the grinding wheel 124 will be described with reference to FIG. The rotation center P 1 of the chuck table 11 and the rotation center P 2 of the annular grinding wheel 126 are eccentric, and the outer diameter of the annular grinding wheel 126 is the boundary line between the device region 104 and the outer peripheral surplus region 105 of the semiconductor wafer 100. The diameter is set to be smaller than the diameter of the boundary line 106 and larger than the radius of the boundary line 106, and the annular grinding wheel 126 passes through the rotation center P 1 of the chuck table 11 (the center of the semiconductor wafer 100).

  Next, as shown in FIGS. 8 and 9, while rotating the chuck table 11 in the direction indicated by the arrow 11a at 300 rpm, the grinding wheel 124 is rotated in the direction indicated by the arrow 124a at 6000 rpm, and the grinding wheel 124 is moved downward. The grinding wheel 126 is moved and brought into contact with the back surface of the semiconductor wafer 100. Then, the grinding wheel 124 is ground by a predetermined amount at a predetermined grinding feed speed. As a result, on the back surface of the semiconductor wafer 100, a region corresponding to the device region 104 is ground and removed to form a circular recess 104b having a predetermined thickness (for example, 60 μm) as shown in FIG. In the illustrated embodiment, the region corresponding to the region 105 is left with a thickness of 350 μm to form the annular reinforcing portion 105b (annular reinforcing portion forming step).

  As described above, the region corresponding to the device region 104 is ground and removed on the back surface of the semiconductor wafer 100 to form the concave portion 104b having a predetermined thickness (for example, 60 μm), and the region corresponding to the outer peripheral surplus region 105 is left to be annular. If the reinforcing portion 105b is formed, the back surface corresponding to the device region 104 is etched, the back surface is coated with a metal film, a via hole is formed, and the like, and then the device region 104 is moved to the street. Although it cut | disconnects along 101 and divides | segments into each semiconductor chip, the cyclic | annular reinforcement part 105b becomes an obstacle. Therefore, it is necessary to cut the boundary between the device region 104 and the outer peripheral surplus region 105 in the semiconductor wafer 100 and remove the annular reinforcing portion 105b. However, when the boundary between the device region 104 and the outer peripheral surplus region 105 in the semiconductor wafer 100 is cut by the cutting blade of the cutting device, the cutting blade and the semiconductor wafer are cut when the cutting blade is cut into an arc shape as described above. There is a problem that a large load is applied to 100 and not only the cutting blade is broken, but also the device region 104 of the thinly formed semiconductor wafer 100 is damaged.

Therefore, the present inventor has considered that grinding is effective for removing the annular reinforcing portion 105b without damaging the device region 104 of the semiconductor wafer 100.
Hereinafter, a grinding wheel and a grinding method suitable for removing the annular reinforcing portion 105b by grinding will be described with reference to FIGS.
FIG. 1 shows a perspective view of a grinding apparatus equipped with a grinding wheel constructed in accordance with the present invention. The grinding apparatus shown in FIG. 1 is provided with an apparatus housing generally indicated by numeral 2. This device housing 2 has a rectangular parallelepiped main portion 21 that extends long and an upright wall 22 that is provided at the rear end portion (upper right end in FIG. 1) of the main portion 21 and extends substantially vertically upward. ing. A pair of guide rails 221 and 221 extending in the vertical direction are provided on the front surface of the upright wall 22. A grinding unit 3 as grinding means is mounted on the pair of guide rails 221 and 221 so as to be movable in the vertical direction.

  The grinding unit 3 includes a moving base 31 and a spindle unit 4 mounted on the moving base 31. The movable base 31 is provided with a pair of legs 311 and 311 extending in the vertical direction on both sides of the rear surface. The pair of legs 311 and 311 is slidably engaged with the pair of guide rails 221 and 221. Guided grooves 312 and 312 are formed. As described above, a support portion 313 protruding forward is provided on the front surface of the movable base 31 slidably mounted on the pair of guide rails 221 and 221 provided on the upright wall 22. The spindle unit 4 is attached to the support portion 313.

  The spindle unit 4 includes a spindle housing 41 mounted on the support portion 313, a rotary spindle 42 rotatably disposed on the spindle housing 41, and a servo motor as a drive source for rotationally driving the rotary spindle 42. 43. One end (lower end in FIG. 1) of the rotary spindle 42 rotatably supported by the spindle housing 41 is disposed so as to protrude from the lower end of the spindle housing 41, and a wheel mount is mounted on one end (lower end in FIG. 1). 44 is provided. The grinding wheel 5 is attached to the lower surface of the wheel mount 44.

The wheel mount 44 and the grinding wheel 5 will be described with reference to FIGS. FIG. 2 is an exploded perspective view showing the wheel mount 44 and the grinding wheel 5, and FIG. 3 is a cross-sectional view of the grinding wheel 5.
As shown in FIG. 2, four bolt insertion holes 441 are formed in the wheel mount 44, and the fastening bolts 6 are inserted into the four bolt insertion holes 441, respectively.

  The grinding wheel 5 shown in FIGS. 2 and 3 includes a disc-shaped wheel base 51, a first grinding wheel 52 mounted on a grindstone mounting surface which is a lower surface of the disc-shaped wheel base 51, and a second grinding wheel 52. It consists of a grinding wheel 53. The disc-shaped wheel base 51 includes a mounting surface 511 that is detachably mounted on the lower surface of the wheel mount 44, and a grindstone mounting surface 512 that is formed on the opposite side of the mounting surface 511. On the mounting surface 511 side of the disk-shaped wheel base 51, a female screw hole 511a is formed at a position corresponding to the bolt insertion hole 441 formed in the wheel mount 44 as shown in FIG. A first grindstone mounting portion 513 for mounting the first grinding wheel 52 and a second grindstone for mounting the second grinding wheel 53 are mounted on the grindstone mounting surface 512 of the disk-shaped wheel base 51. A mounting portion 514 is provided. The first grindstone mounting portion 513 is formed in an annular shape around the rotation center of the disk-shaped wheel base 51, and is formed so as to protrude in the axial direction from the second grindstone mounting portion 514. An annular first grindstone mounting groove 513a is formed on the first grindstone mounting portion 513 formed in an annular shape. On the other hand, the second grindstone mounting portion 514 is formed with an annular second grindstone mounting groove 514 a that surrounds the first grindstone mounting portion 513 and is centered on the rotation center of the disk-shaped wheel base 51.

  In the illustrated embodiment, the first grinding wheel 52 is composed of a plurality of finishing wheel segments 52a, and is formed on the first wheel mounting portion 513 of the disk-shaped wheel base 51. The bases of the plurality of finishing grindstone segments 52a are fitted into the mounting grooves 513a and fixed to the first grindstone mounting section 513 with an adhesive. The second grinding wheel 53 is composed of a plurality of coarse grinding wheel segments 53a in the illustrated embodiment, and is a second annular wheel formed on the second grinding wheel mounting portion 514 of the disk-shaped wheel base 51. The bases of the plurality of coarse grindstone segments 53a are fitted into the grindstone mounting grooves 514a and fixed to the second grindstone mounting part 514 with an adhesive. In this way, the grinding surface (lower surface) of the first grinding wheel 52 composed of the plurality of finishing grinding wheel segments 52a mounted on the first grinding wheel mounting portion 513 of the disk-shaped wheel base 51 is mounted on the second grinding wheel. It is configured to protrude in the axial direction from the grinding surface (lower surface) of the second grinding wheel 53 composed of a plurality of coarse grinding wheel segments 53 a mounted on the portion 514.

  The grinding wheel 5 configured as described above has a mounting surface 511 detachably mounted on the lower surface of the wheel mount 44. That is, by inserting the fastening bolt 6 into the bolt insertion hole 441 formed in the wheel mount 44 and screwing this fastening bolt 6 into the female screw hole 511a formed on the mounting surface 511 side of the wheel base 51, The grinding wheel 5 is detachably attached to the wheel mount 44.

  Referring back to FIG. 1, the grinding apparatus in the illustrated embodiment moves the grinding unit 3 up and down along the pair of guide rails 221 and 221 (perpendicular to a holding surface of a chuck table described later). A grinding unit feed mechanism 7 that is moved in the direction). The grinding unit feed mechanism 7 includes a male screw rod 71 disposed on the front side of the upright wall 22 and extending substantially vertically. The male screw rod 71 is rotatably supported by bearing members 72 and 73 whose upper end and lower end are attached to the upright wall 22. The upper bearing member 72 is provided with a pulse motor 74 as a drive source for rotationally driving the male screw rod 71, and an output shaft of the pulse motor 74 is transmission-coupled to the male screw rod 71. A connecting portion (not shown) that protrudes rearward from the center portion in the width direction is also formed on the rear surface of the movable base 31, and a through female screw hole (not shown) that extends in the vertical direction is formed in this connecting portion. The male screw rod 71 is screwed into the female screw hole. Accordingly, when the pulse motor 74 is rotated forward, the moving base 31, that is, the polishing unit 3 is lowered or advanced, and when the pulse motor 74 is reversed, the movable base 31, that is, the grinding unit 3 is raised or moved backward.

  Continuing the description with reference to FIG. 1, the chuck table mechanism 8 is disposed in the main portion 21 of the housing 2. The chuck table mechanism 8 includes a chuck table 81, a cover member 82 that covers the periphery of the chuck table 81, and bellows means 83 and 84 that are disposed before and after the cover member 82. The chuck table 81 is configured to be rotated by a rotation driving unit (not shown), and is configured to suck and hold a wafer as a workpiece on its upper surface by operating a suction unit (not shown). Also, the chuck table 81 is moved between a workpiece placement area 80a shown in FIG. 1 and a grinding area 80b facing the grinding wheel 5 constituting the spindle unit 4 by a chuck table moving means (not shown). The bellows means 83 and 84 can be formed from any suitable material such as campus cloth. The front end of the bellows means 83 is fixed to the front wall of the main portion 21, and the rear end is fixed to the front end surface of the cover member 82. The front end of the bellows means 84 is fixed to the rear end surface of the cover member 82, and the rear end is fixed to the front surface of the upright wall 22 of the apparatus housing 2. When the chuck table 81 is moved in the direction indicated by the arrow 81a, the bellows means 83 is expanded and the bellows means 84 is contracted. When the chuck table 81 is moved in the direction indicated by the arrow 81b, the bellows means 83 is By contracting, the bellows means 84 is extended.

The grinding apparatus in the illustrated embodiment is configured as described above, and a method for removing the annular reinforcing portion 105b formed on the semiconductor wafer 100 described above by this grinding apparatus will be described.
As shown in FIG. 1, the semiconductor wafer 100 on which the above-described annular reinforcing portion 105b is formed is placed on a chuck table 81 positioned in a workpiece placement area 80a of the polishing apparatus. As described above, the protective tape 110 is attached to the surface of the semiconductor wafer 100 where the devices are formed, and the protective tape 110 side is placed on the chuck table 81. Accordingly, in the semiconductor wafer 100, the back surface on which the annular reinforcing portion 105b is formed is the upper side. The semiconductor wafer 100 placed on the chuck table 81 in this way is sucked and held on the chuck table 81 by suction means (not shown). When the semiconductor wafer 100 is sucked and held on the chuck table 81, the chuck table moving means (not shown) is operated to move the chuck table 81 in the direction indicated by the arrow 81a and position it in the grinding zone 80b. Then, as shown in FIG. 4, the annular reinforcing portion 105 b formed in the semiconductor wafer 100 is positioned at a position where the plurality of coarse grinding stone segments 53 a of the second grinding stone 53 constituting the grinding wheel 5 pass.

  If the semiconductor wafer 100 held on the grinding wheel 5 and the chuck table 81 is set in the positional relationship shown in FIG. 4, the chuck table 81 is rotated in the direction indicated by the arrow at a rotational speed of, for example, 300 rpm, The grinding wheel 5 is rotated at a rotational speed of, for example, 6000 rpm in the direction indicated by the arrow. Then, the grinding wheel 5 is lowered to press the second grinding wheel 53 composed of a plurality of coarse grinding wheel segments 53 a onto the upper surface of the annular reinforcing portion 105 b formed on the semiconductor wafer 100 with a predetermined pressure. As a result, the annular reinforcing portion 105b formed on the semiconductor wafer 100 is roughly ground (rough grinding process). In this rough grinding process, grinding is performed to a thickness that leaves a finishing allowance in the thickness (for example, 60 μm) of the device region 104 of the semiconductor wafer 100.

  When the above-described rough grinding step is performed, the grinding wheel 5 is raised, the chuck table 81 is moved, and the annular reinforcing portion 105b formed on the semiconductor wafer 100 is configured as shown in FIG. The first grinding wheel 52 is positioned at a position where the plurality of finishing wheel segments 52a pass. Then, the chuck table 81 is rotated in the direction indicated by an arrow at a rotational speed of, for example, 300 rpm, the grinding wheel 5 is rotated in the direction indicated by an arrow, for example, at a rotational speed of 6000 rpm, and the grinding wheel 5 is moved down to a plurality of finishing wheels. The first grinding wheel 52 composed of the segment 52a is pressed against the upper surface of the annular reinforcing portion 105b formed on the semiconductor wafer 100 and roughly ground as described above with a predetermined pressure. As a result, the annular reinforcing portion 105b roughly ground as described above is finish ground (finish grinding step). In this finish grinding step, grinding is performed until the annular reinforcing portion 105b reaches the thickness (for example, 60 μm) of the device region 104 of the semiconductor wafer 100. As a result, the annular reinforcing portion 105b is removed.

  By using the grinding wheel 5 as described above, rough grinding and finish grinding are performed without interfering with the annular reinforcing portion 105b formed on the semiconductor wafer 100 by one grinding wheel. The reinforcing portion 105b can be removed. The outer diameter of the first grinding wheel 52 constituting the above-described grinding wheel 5 is smaller than the diameter of the boundary line 106 between the device region 104 and the outer peripheral surplus region 105 of the semiconductor wafer 100, and larger than the radius of the boundary line 106, and By setting the grinding surface of the grindstone segment 52a of the first grinding grindstone 52 to pass through the center of the semiconductor wafer 100, the above-described annular reinforcing portion forming step can be performed. In this case, the protrusion amount of the grinding surface of the first grinding wheel 52, that is, the protrusion amount of the second grinding wheel 53 from the grinding surface is set to be larger than the height of the annular reinforcing portion 105 b formed on the back surface of the semiconductor wafer 100. There is a need to.

  As described above, by performing the rough grinding process and the finish grinding process on the annular reinforcing portion 105b formed on the semiconductor wafer 100, the annular reinforcing portion 105b is removed, and the outer peripheral region 105 of the semiconductor wafer 100 is removed. The back surface and the back surface of the device region 104 are on the same plane. Therefore, the back surface of the semiconductor wafer 100 can be attached to the dicing tape, and the semiconductor wafer 100 can be cut along the street 101.

  Although the present invention has been described based on the illustrated embodiment, the present invention is not limited to the embodiment, and various modifications can be made within the scope of the gist of the present invention. For example, in the above-described embodiment, an example in which the first grinding wheel 52 is a plurality of finishing wheel segments 52 a and the second grinding wheel 53 is a plurality of rough grinding stone segments 53 a has been described. The second grinding wheel 53 may be constituted by a plurality of finishing wheel segments 52a. When the annular reinforcing portion 105b formed on the semiconductor wafer 100 is ground by the grinding wheel configured as described above, the grinding order is reversed.

1 is a perspective view of a grinding apparatus equipped with a grinding wheel constructed according to the present invention. The wheel mount with which the grinding apparatus shown in FIG. 1 is equipped, and the perspective view of the grinding wheel comprised according to this invention. Sectional drawing of the grinding wheel shown in FIG. Explanatory drawing of the rough grinding process implemented by the 2nd grinding wheel of the grinding wheel shown in FIG. Explanatory drawing of the finish grinding process implemented with the 1st grinding wheel of the grinding wheel shown in FIG. The perspective view of the semiconductor wafer as a wafer processed with the grinding wheel comprised according to this invention. FIG. 7 is a perspective view illustrating a state in which a protective member is attached to the surface of the semiconductor wafer illustrated in FIG. 6. FIG. 7 is a perspective view of a grinding apparatus for grinding the back surface of the semiconductor wafer shown in FIG. 6. Explanatory drawing of the reinforcement part formation process implemented with the grinding apparatus shown in FIG. Sectional drawing of the semiconductor wafer in which the reinforcement part formation process shown in FIG. 9 was implemented.

Explanation of symbols

2: Device housing 3: Grinding unit 31: Moving base 4: Spindle unit 41: Spindle housing 42: Rotating spindle 43: Servo motor 44: Wheel mount 5: Grinding wheel 51: Disk-shaped wheel base 52: First Grinding wheel 52a: Finishing wheel segment 53: Second grinding wheel 53a: Finishing wheel segment 7: Grinding unit feed mechanism 8: Chuck table mechanism 81: Chuck table 100: Semiconductor wafer 110: Protective tape

Claims (2)

A grinding wheel for grinding a workpiece mounted on a wheel mount attached to a rotating spindle of a grinding apparatus and held on a chuck table,
A disc-shaped wheel base having a mounting surface detachably mounted on the lower surface of the wheel mount and a grindstone mounting surface formed on the opposite side of the mounting surface;
A first grinding wheel disposed in an annular shape around the center of rotation of the disk-shaped wheel base on the surface of the disk-shaped wheel base, and the wheel mounting of the disk-shaped wheel base A first grinding wheel surrounding the first grinding wheel, and a second grinding wheel disposed in an annular shape around the center of rotation of the disk-shaped wheel base,
The grinding surface of the first grinding wheel is configured to protrude in the axial direction from the grinding surface of the second grinding wheel.
A grinding wheel characterized by that.   The grinding wheel according to claim 1, wherein one of the first grinding wheel and the second grinding wheel is formed by a rough grinding wheel, and the other is formed by a finish grinding wheel.

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