JP2022047397A - Processing method of primal wafer - Google Patents

Abstract

To provide a processing method of a primal wafer which can process a primal wafer efficiently.SOLUTION: A processing method of a primal wafer includes: a first grinding step in which a primal wafer 10 is held on a rotary chuck table 61, including a holding surface 63 for holding a workpiece, and grinding means 4 rotatably including a grinding wheel 45 with abrasive wheels 46, which are disposed in an annular form while facing the holding surface 63, is moved close to the chuck table 61, and the grinding wheel 45 is rotated so that the abrasive wheels 46 pass through a rotation center of the primal wafer 10 held by the chuck table 61 to grind one surface 10a of the primal wafer 10; and a first chamfering step in which the chuck table 61 and the grinding means 4 are moved relative to each other in a direction parallel to the holding surface 63, the abrasive wheels 46 are positioned at an outer peripheral corner part 10c of the one surface 10a, and an outer periphery of the one surface 10a of the primal wafer 10 is chamfered with the abrasive wheels 46.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method for processing a primitive wafer generated from an ingot.

A wafer formed on the upper surface of a silicon substrate in which a plurality of devices such as ICs and LSIs are divided by a planned division line is divided into individual device chips by a dicing device and a laser processing device, and is used for electric devices such as mobile phones and personal computers. It will be used.

Further, the so-called primitive wafer before the device is formed on the surface is generated by slicing an ingot such as Si to a thickness of about 1 mm by a cutting device equipped with an inner peripheral blade, a wire saw, or the like (for example, Patent Document 1). See). Then, both sides of the primitive wafer generated from the ingot are ground, and then the outer peripheral corners are chamfered using a special jig to make the device suitable for forming the device on the upper surface. Will be done.

Japanese Unexamined Patent Publication No. 08-155948

In the method of processing a primitive wafer in the prior art, grinding is performed until a device is formed on the surface thereof, and then a plurality of processes such as chamfering are performed using a dedicated device or jig. There is a problem of poor productivity because it needs to go through.

The present invention has been made in view of the above facts, and a main technical problem thereof is to provide a processing method for a primitive wafer capable of efficiently processing a primitive wafer.

In order to solve the above-mentioned main technical problem, according to the present invention, a method for processing a primitive waha generated from an ingot, which is a rotatable chuck table provided with a holding surface for holding a work piece. A grinding means provided with a primordial waha holding step for holding the primordial waha and a grindstone rotatably provided with a grinding wheel in which a grinding wheel is annularly arranged facing the holding surface is brought close to the chuck table and held on the chuck table. A first grinding step of rotating the grinding wheel so that the grinding wheel passes through the center of rotation of the primitive waha to grind one surface of the primordial waher, and holding the chuck table and the grinding means. The first outer peripheral positioning step of moving the grinding wheel relatively in a direction parallel to the surface to position the grinding wheel above the outer peripheral corner of one surface, and chamfering the outer periphery of one surface of the primitive wafer with the grinding wheel. The first chamfering step is configured to include the first chamfering step, in which the chuck table and the grinding means are relatively tilted, and the grinding wheel is formed on the outer periphery of one surface of the primitive wafer. Is provided, and a method for processing a primitive waher is provided in which a chamfering portion is formed on one surface of the chuck table by grinding it in close proximity to the chuck table.

Further, one surface that has been ground is held on the chuck table, and the grinding wheel is rotated so that the grinding wheel passes through the rotation center of the primitive waha held on the chuck table, and the other surface of the primitive waha is rotated. A second grinding step of grinding, and a second, in which the chuck table and the grinding means are relatively moved in a direction parallel to the holding surface, and the grinding wheel is positioned above the outer peripheral corner of the other surface. It is configured to include an outer peripheral positioning step and a second chamfering step of chamfering the outer periphery of the other surface of the primitive wafer with the grinding wheel, and the second chamfering step includes the chuck table and the grinding. It is also possible to tilt the means relatively and position the grinding grind on the outer periphery of the other surface of the primitive waher, and to grind it close to the chuck table to form a chamfered portion on the other surface.

The method for processing a primitive waha of the present invention is a method for processing a primordial waha generated from an ingot, and the primordial waha is held on a rotatable chuck table provided with a holding surface for holding a workpiece. The primitive waha holding step of the primitive waha and the grinding means provided with a grindstone in which a grinding wheel is arranged in an annular shape facing the holding surface are brought close to the chuck table and held on the chuck table. The first grinding step of rotating the grinding wheel so that the grinding wheel passes through the center of rotation to grind one surface of the primitive wafer, and the direction in which the chuck table and the grinding means are parallel to the holding surface. The first outer peripheral positioning step of locating the grinding wheel above the outer peripheral corner of one surface, and the first chamfering process of chamfering the outer periphery of one surface of the primitive wafer with the grinding wheel. The first chamfering process includes a processing step, in which the chuck table and the grinding means are relatively tilted, the grinding wheel is positioned on the outer periphery of one surface of the primitive wafer, and the grinding wheel is positioned. Since the chamfering portion is formed on one surface by approaching the chuck table and grinding, the first grinding step of grinding one surface of the primitive wafer and the first chamfering process on the outer periphery of one surface are performed. The chamfering process can be carried out in a continuous process without changing the processing device or jig, and the productivity is improved.

It is an overall perspective view of the grinding apparatus which can carry out the processing method of this embodiment. It is a perspective view which shows the embodiment of the primitive wafer holding process. It is a perspective view which shows the embodiment of the 1st grinding process. (A) is a perspective view showing an embodiment of the first chamfering process, and (b) is a schematic side view when performing the processing shown in (a). It is a perspective view which shows the embodiment of the 2nd grinding process. (A) is a perspective view showing an embodiment of a second chamfering process, and (b) is a schematic side view when performing the processing shown in (a).

Hereinafter, embodiments relating to a processing method for a primitive wafer configured based on the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an overall perspective view of the grinding apparatus 1 suitable for carrying out the processing method of the primitive wafer of the present embodiment. The grinding device 1 shown in FIG. 1 includes a device housing 2 having a substantially rectangular parallelepiped shape, an upright wall 3 erected on the rear end side of the device housing 2, a grinding means 4 for grinding a workpiece, and a workpiece. It is provided with a chuck table mechanism 6 for holding the above.

As shown in the figure, the chuck table mechanism 6 includes a disk-shaped suction chuck 61a and a frame body 61b surrounding the suction chuck 61a, and is configured to be rotatable by a rotation drive source (not shown), and a chuck table 61. The figure of the rectangular cover plate 62 that projects upward and covers the periphery of the chuck table 61, the first bellows body 64a connected to the direction side indicated by the arrow Y1 in the figure of the cover plate 62, and the cover plate 62. It is provided with a second bellows body 64b connected to the direction side indicated by the middle arrow Y2. The suction chuck 61a is formed of a porous member having air permeability, is connected to a suction source (not shown), and by operating the suction source, a negative pressure is supplied to the holding surface 63 of the suction chuck 61a to supply the holding surface. The workpiece placed on 63 can be sucked and held. The Y-axis direction shown in FIG. 1 is a direction orthogonal to the X-axis direction, and the holding surface 63 in normal times is a surface defined in the X-axis direction and the Y-axis direction shown in FIG. 1, and X. The plane defined by the axial direction and the Y-axis direction is substantially horizontal.

The cover plate 62 includes an upper plate portion 62a, a lower plate portion 62b, and a lift mechanism (not shown), and by operating the lift mechanism, the upper plate portion 62a is shown on the lower right side in the drawing. In the figure, the side on the Y2 side rises and separates from the lower plate portion 62b, and can be tilted toward the Y1 side in the figure. A third bellows body 64c is disposed between the upper plate portion 62a and the lower plate portion 62b, and the grinding water to be processed by the grinding means 4 is inside the device housing 2 of the grinding device 1. Prevent entry into.

Inside the device housing 2, a moving means (not shown) for moving the chuck table mechanism 6 in the Y-axis direction is housed. By operating the moving means, the chuck table mechanism 6 is placed in the front side (direction indicated by the arrow Y1) in the drawing in which the unprocessed workpiece is placed on the chuck table 61, and the chuck table 61. It can be moved to and from the processing region on the inner side (direction indicated by the arrow Y2) in the drawing in which the workpiece held in the drawing is ground by the grinding means 4.

The grinding means 4 is mounted on a moving base 4a arranged on the front surface of the upright wall 3, and the moving base 4a is a pair of guide rails arranged on the upright wall 3 of the device housing 2 on the rear surface side. It engages with 31 and 31 and is slidably mounted on the guide rails 31 and 31 in the Z-axis direction (vertical direction) in the drawing.

The grinding means 4 includes a spindle housing 42 supported by a support portion 4b integrally formed with the moving base 4a, a rotary spindle 43 rotatably held by the spindle housing 42, and rotary drive means for the rotary spindle 43. It is provided with an arranged electric motor 41. The lower end portion of the rotary spindle 43 projects toward the lower end side of the spindle housing 42, and a wheel mount 44 is arranged at the lower end portion thereof. A grinding wheel 45 is mounted on the lower surface of the wheel mount 44, and the lower surface of the grinding wheel 45 faces the holding surface 63 of the chuck table 61 when the chuck table 61 is positioned in the machining area directly below the grinding wheel 45. A plurality of grinding wheels 46 are arranged in an annular shape so as to be used. The grinding water L supplied from the grinding water supply means (not shown) is introduced from the upper end portion 43a of the rotary spindle 43 and is supplied to the machining region from the center of the lower end surface of the grinding wheel 45 via the passage in the rotary spindle 43. Will be done.

The grinding apparatus 1 shown in FIG. 1 includes a grinding feed means 7 for moving the grinding means 4 along the pair of guide rails 31 and 31 in the Z-axis direction (direction perpendicular to the holding surface 63 of the chuck table 61). There is. The grinding feed means 7 includes a male screw rod 71 arranged on the front surface side of the upright wall 3 and extending in the vertical direction, and a pulse motor 72 as a drive source for rotationally driving the male screw rod 71. The upper end and the lower end of the male screw rod 71 are rotatably supported by the upright wall 3, and the output shaft of the pulse motor 72 is connected to the upper end of the male screw rod 71. A screw connecting portion (not shown) is formed on the rear surface of the moving base 4a, and a female screw hole extending in the vertical direction is formed in the connecting portion, and the male screw rod 71 is placed in the female screw hole. Be screwed. The grinding feed means 7 having such a screw mechanism rotates the pulse motor 72 in the normal direction to lower the grinding means 4 together with the moving base 4a, reverses the pulse motor 72, and raises the grinding means 4 together with the moving base 4a. Can be made to.

The grinding device 1 includes a control means (not shown), to which a grinding means 4, a grinding feeding means 7, a moving means (not shown) and the like are connected, and each of them is based on an arbitrary control program. The means are precisely controlled.

The grinding device 1 shown in FIG. 1 has substantially the same configuration as described above, and the method for processing the primitive wafer of the present embodiment, which is carried out using the grinding device 1, will be described below.

FIG. 2 shows a primitive wafer 10 made of silicon (Si), which is a workpiece of the present embodiment. The primitive wafer 10 is, for example, a circular plate-shaped wafer having a thickness of about 1 mm and having a diameter of about 100 mm cut out by slicing a columnar single crystal ingot (not shown), and has either a front surface or a back surface. It is a wafer in which no device or the like is formed.

In carrying out the processing method of the primitive wafer of the present embodiment, as shown in FIG. 2, one surface 10a of the primitive wafer 10 is upward with respect to the holding surface 63 of the chuck table 61 positioned in the carry-in / out area. The other surface 10b is placed and held downward (primitive wafer holding step). At this time, the primitive wafer 10 is placed so that the center of the primitive wafer 10 and the center of the chuck table 61 coincide with each other, and a suction source (not shown) is operated to supply a negative pressure to the holding surface 63. Is sucked and held on the holding surface 63 of the chuck table 61. In the primitive wafer 10 of the present embodiment, after being cut out from the ingot, neither the front surface nor the back surface is processed, and there is no distinction between the front surface and the back surface. However, for convenience of explanation. The surface to be processed first is referred to as "one surface", and the surface on the opposite side is referred to as "the other surface".

After the above-mentioned primitive wafer holding step is performed, the moving means is operated to move the chuck table 61 to the processing region as shown in FIG. Next, the grinding feed means 7 is operated to bring the grinding means 4 closer to the chuck table 61, and the electric motor 41 of the grinding means 4 is operated to rotate the grinding wheel 45 in the direction indicated by the arrow R1 at, for example, 6000 rpm. , The chuck table 61 is rotated in the direction indicated by the arrow R2 at a rotation speed of, for example, 300 rpm. Further, the grinding wheel 45 is positioned so that the grinding wheel 46 passes through the rotation center O of the primitive wafer 10 held on the chuck table 61, and the grinding feeding means 7 is operated to move the grinding means 4 in the direction indicated by the arrow R3, for example. The one surface 10a of the primitive wafer 10 is brought into contact with one surface 10a at a descending speed of 1.0 μm / sec, and one surface 10a of the primitive wafer 10 is ground by a predetermined amount (first grinding step). When carrying out the first grinding step, it is preferable to carry out the first grinding step while detecting the amount of grinding by using a thickness detecting means (not shown).

When the first grinding step described above is carried out, the chuck table 61 and the grinding means 4 are held in a state where the grinding feed means 7 is operated to raise the grinding means 4 once and the primitive waha 10 is sucked and held on the chuck table 61. Is relatively moved in a direction parallel to the holding surface 63 of the chuck table 61 (in this embodiment, the chuck table 61 is moved in the direction indicated by the arrow Y1 in FIG. 1), and the grinding wheel 46 is moved to one surface. It is positioned above the outer peripheral corner portion 10c of 10a (first outer peripheral positioning step).

After the first outer peripheral positioning step is carried out, the first chamfering step of chamfering the outer peripheral corner portion 10c of one surface 10a of the primitive wafer 10 with the grinding wheel 46 is carried out. In carrying out the first chamfering process, as shown by an arrow R4 in FIG. 4A, the lift mechanism (not shown) constituting the cover table 62 is operated to operate the cover table 62. The arrow Y2 side of the upper plate portion 62a is raised and tilted toward the arrow Y1 side. After that, while lowering the grinding wheel 46 in the direction indicated by the arrow R3 so as to approach the chuck table 61, as shown in FIG. 4B, the grinding wheel 46 is placed on the outer peripheral corner portion 10c of the primitive wafer 10 held by the chuck table 61. The outer peripheral corner portion 10c is ground by abutting. As a result, a chamfered portion 11 having an inclination angle corresponding to the inclination of the chuck table 61 is formed on the outer peripheral angle portion 10c of one surface 10a (first chamfering process).

The first chamfering step of the present embodiment is continuously carried out in the first grinding step described above, and the grinding wheel 45 of the grinding means 4 and the chuck table 61 rotate during the first grinding step described above. Is carried out while being maintained. However, the present invention is not limited to this, and the rotation of the grinding wheel 45 and the chuck table 61 may be temporarily stopped when shifting from the first grinding process to the first chamfering process. Further, as shown in FIG. 4B, the chamfered portion 11 formed by the present embodiment is formed of a tapered surface having a linear cross section, but when the first chamfering process is performed, the chamfered portion 11 is formed. By adjusting the lift mechanism that controls the inclination angle of the upper plate portion 62a of the cover table 62, the grinding feed mechanism 7 of the grinding means 4, and the moving means that moves the chuck table 61 in the Y-axis direction, the cross section can be changed. It is also possible to form a chamfered portion 11 that is curved.

According to the above-mentioned processing method of the primitive waha, the processing apparatus includes a first grinding step of grinding one surface 10a of the primitive waha 10 and a first chamfering process of performing chamfering on the outer periphery of the one surface 10a. It can be carried out in a continuous process without changing the jig or jig, and productivity is improved.

According to the processing method of the primitive wafer of the present embodiment, after the first grinding step and the first chamfering step described above are carried out, the second grinding step and the second chamfering step described below are performed. Can also be carried out.

After the above-mentioned first grinding step and first chamfering step are performed, the lift mechanism is operated to set the inclination angle of the upper plate portion 62a of the cover table 62 in the X-axis direction and the Y-axis direction. Returning to a state parallel to the horizontal plane defined by the above, the moving means of the chuck table 61 is operated to move the chuck table 61 to the loading / unloading region, and the suction source for supplying negative pressure to the chuck table 61 is used. Stop. Next, the primitive wafer 10 is removed from the chuck table 61, the front and back sides are reversed, the other surface 10b of the primitive wafer 10 is directed upward, and the one surface 10a is directed downward, and the center of the chuck table 61 and the center of the primitive wafer 10 are directed. The wafer is placed on the holding surface 63 of the chuck table 61 so as to coincide with the above, and the suction source is operated to suck and hold the primitive wafer 10 on the chuck table 61 (except for the difference between the front and back sides, referring to FIG. 2). The process is similar to the process described).

Next, the moving means is operated to move the chuck table 61 to the machining region in the direction indicated by the arrow Y2 in FIG. 1, and the grinding feed means 7 is operated to bring the grinding means 4 closer to the chuck table 61. As shown in FIG. 5, the grinding wheel 45 is positioned so that the grinding wheel 46 passes through the center O of the primitive waha 10 held by the chuck table 61. Then, the electric motor 41 of the grinding means 4 is operated to rotate the grinding wheel 45 in the direction indicated by the arrow R1 at, for example, 6000 rpm, and the chuck table 61 is rotated in the direction indicated by the arrow R2 at a rotation speed of, for example, 300 rpm. , The above-mentioned grinding feed means 7 is operated to bring the grinding means 4 into contact with the other surface 10b of the primitive waha 10 in the direction indicated by the arrow R3 at a descending speed of, for example, 1.0 μm / sec. Surface 10b is ground by a predetermined amount (second grinding step).

When the second grinding step described above is carried out, the chuck table 61 and the grinding means 4 are held in a state where the grinding feed means 7 is operated to raise the grinding means 4 once and the primitive waha 10 is sucked and held by the chuck table 61. Is relatively moved in a direction parallel to the holding surface 63 of the chuck table 61 (in this embodiment, the chuck table 61 is moved in the direction indicated by the arrow Y1 in FIG. 1), and the grinding wheel 46 is moved to the other side. It is positioned above the outer peripheral corner portion 10d of the surface 10b (second outer peripheral positioning step).

After the second outer peripheral positioning step is carried out, the second chamfering step of chamfering the outer peripheral corner portion 10d of the other surface 10b of the primitive wafer 10 with the grinding wheel 46 is carried out. When carrying out the second chamfering step, as shown in FIG. 6A, the lift mechanism constituting the cover table 62 (not shown) is the same as the first chamfering step. As shown by arrow R4, the upper plate portion 62a of the cover table 62 is raised on the arrow Y2 side, and the chuck table 61 is tilted toward the arrow Y1. After that, the grinding wheel 46 is lowered in the direction indicated by the arrow R3 so as to approach the chuck table 61, and is brought into contact with the outer peripheral corner portion 10d of the primitive waha 10 held by the chuck table 61. As shown, the outer peripheral corner portion 10d is ground to form a chamfered portion 12 having an inclination angle corresponding to the inclination of the chuck table 61 on the outer peripheral corner portion 10d of the other surface 10b (second chamfering step).

The second chamfering step of the present embodiment is continuously carried out in the second grinding step described above, and the grinding wheel 45 of the grinding means 4 and the chuck table 61 are in the second grinding step described above. It is carried out while the rotation is maintained. However, the present invention is not limited to this, and the rotation of the grinding wheel 45 and the chuck table 61 may be temporarily stopped when shifting from the second grinding process to the second chamfering process. Further, as shown in FIG. 6B, the chamfered portion 12 formed by the present embodiment is formed of a tapered surface having a linear cross section, but in the column of the first chamfering process described above. As described, it is also possible to form the cross section so as to be curved.

According to the above-mentioned processing method of the primitive waha, the processing apparatus includes a second grinding step of grinding the other surface 10b of the primitive waha 10 and a second chamfering process of performing chamfering on the outer periphery of the other surface 10b. It can be carried out in a continuous process without changing the jig or jig, and productivity is improved.

In the above-described embodiment, as a means for relatively tilting the chuck table 61 and the grinding means 4, a lift mechanism for tilting the upper plate portion 62a of the cover table 62 is provided on the table mechanism 6 side, and the lift mechanism is operated. The chuck table 61 is tilted, but the present invention is not limited to this. For example, the lift mechanism is arranged on the moving base 4a side of the grinding means 4, and the angle of the moving base 4a is changed for grinding. It is also possible to configure the wheel 45 so that the angle with respect to the chuck table 61 can be changed so that the chuck table 61 and the grinding means 4 are relatively tilted.

1: Grinding device 2: Equipment housing 3: Upright wall 31: Guide rail 4: Grinding means 4a: Moving base 4b: Support portion 41: Electric motor 42: Spindle housing 43: Rotating spindle 44: Wheel mount 45: Grinding wheel 46 : Grinding wheel 6: Table mechanism 61: Chuck table 61a: Suction chuck 61b: Frame body 62: Cover table 62a: Upper plate portion 62b: Lower plate portion 63: Holding surface 64a: First bellows portion 64b: Second bellows portion 64c : Third bellows portion 7: Grinding feed means 71: Male screw rod 72: Pulse motor 10: Primitive waha 10a: One surface 10b: The other surface 10c: Outer peripheral corner portion 10d: Outer peripheral corner portion 11, 12: Chamfered portion

Claims (2)

It is a processing method of a primitive wafer that processes a primitive wafer generated from an ingot.
A primitive wafer holding process that holds the primitive wafer on a rotatable chuck table with a holding surface that holds the workpiece,
A grinding means provided with a rotatable grinding wheel having a grinding wheel arranged in an annular shape facing the holding surface is brought close to the chuck table, and the grinding wheel is centered on the rotation center of the primitive waha held by the chuck table. The first grinding step of grinding one side of the primitive waher by rotating the grinding wheel to pass through,
A first outer peripheral positioning step of moving the chuck table and the grinding means relatively in a direction parallel to the holding surface to position the grinding wheel above the outer peripheral corner of one surface.
It is configured to include a first chamfering step of chamfering the outer periphery of one surface of a primitive wafer with the grinding wheel.
In the first chamfering step, the chuck table and the grinding means are relatively tilted, the grinding wheel is positioned on the outer periphery of one surface of the primitive wafer, and the grinding wheel is brought close to the chuck table for grinding. A method for processing a primitive waha that forms a chamfered portion on one of the surfaces. One surface that has been ground is held on the chuck table, and the grinding wheel is rotated so that the grinding wheel passes through the rotation center of the primitive wafer held on the chuck table to grind the other surface of the primitive wafer. The second grinding process and
A second outer peripheral positioning step of moving the chuck table and the grinding means relatively in a direction parallel to the holding surface to position the grinding wheel above the outer peripheral corner of the other surface.
It is configured to include a second chamfering step of chamfering the outer periphery of the other surface of the primitive wafer with the grinding wheel.
In the second chamfering step, the chuck table and the grinding means are relatively tilted, the grinding wheel is positioned on the outer periphery of the other surface of the primitive wafer, and the grinding wheel is brought close to the chuck table for grinding. The method for processing a primitive wafer according to claim 1, wherein a chamfered portion is formed on the other surface.

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