JPH09136249A - Wafer machining device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently shape wafers, which are different in outside diameters, or a non-circular wafer into circles with a fixed diameter by means of a single device. SOLUTION: A grinding wheel block 16 consisting of a punch unit 16C and a chamfering unit 16B integrally is supported on a turntable 26 freely slidably. A wafer 18 is fixed on a wafer table 20 arranged coaxially with the turntable 26. The turntable 26 is rotated and lowered toward the wafer 18, and the punching unit 16C in the grinding wheel block 16 is brought into contact with the surface of the wafer 18. In this way, the wafer 18 is punched out into a circle. The upper part, of the circumference edge of the punched circle wafer 18 is brought into contact with the lower slanting face 16b1 in the chamfering unit 16B, and chamfering of the upper part of the circumferential edge of the wafer 18 is carried out The lower part of the circumferential edge of the wafer 18 is brought into contact with the upper slanting face 16b2 in the chamfering unit 16B, and the lower part of the circumferential edge of the wafer 18 is carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer processing apparatus, and more particularly to a wafer processing apparatus for shaping a non-circular shaped wafer into a circular wafer having a constant diameter.

[0002]

2. Description of the Related Art When gallium arsenide (GaAs) is crystal-grown by the horizontal Bridgman method (HB method), an ingot 1H produced has a D-shaped cross section as shown in FIG. When GaAs is crystal-grown by the Czochralski method (CZ method), the generated ingot 1C has a corrugated peripheral surface, that is, a diameter thereof changes periodically along the axis, as shown in FIG. The shape is obtained.

A wafer is a thin slice of the ingot, and is an ingot 1H crystal-grown by the HB method.
As shown in FIG. 6, the wafer 2H obtained from the above has a rounded triangular shape. On the other hand, the wafer 2C cut out from the ingot 1C crystal-grown by the CZ method has a circular shape with different diameters.

By the way, in the wafer manufacturing process,
The shape of the wafer is standardized into a circle with a constant diameter, and the standard defines the thickness and diameter. Therefore, the wafer cut out from the ingot produced by the HB method or the CZ method needs to be shaped into a circular shape having a constant diameter that meets the standard (see FIG. 8). In addition, silicon (S
In the case of i), since the generated ingot is a cylinder,
The shape of each wafer obtained is a circle with the same diameter. Therefore, it is not necessary to shape it into a circular shape like the GaAs wafer, but if a thin wafer is cut due to a cutting error or if there is a defect in the edge, lower the standard size to reduce the dummy size. It may be used as a wafer or solar cell. In this case, similarly to the GaAs wafer, it is necessary to shape it into a circle having a predetermined diameter (see FIG. 9).

Conventionally, the shaping of the wafer has been performed using an outer diameter grinding machine and a chamfering machine.

[0006]

However, in the above-mentioned conventional method, since two processing machines are used, there are drawbacks that the facility cost is increased and the maintenance is troublesome. Further, when each of the processing machines is used alone, it is inconvenient to store and manage the processed wafers, and in the case of automation, there is a drawback that the apparatus becomes large because a transfer apparatus is required. .

Further, in the case of an outer diameter grinding machine, since the outer diameter of the wafer is shaped into a circle while grinding it with a circular grindstone,
There was a problem that processing efficiency was poor. Furthermore, FIG.
As shown in FIG. 2, when shaping a non-circular wafer into a circular wafer 2H ′, 2S ′ such as a wafer 2H cut from an ingot generated by the HB method or a wafer 2S having an orientation flat, the wafer 2H until it becomes circular, Since 2S is intermittently ground, damage is likely to occur, and the load on the grindstone 3 also increases.

The present invention has been made in view of the above circumstances, and a wafer having a different outer diameter or a non-circular wafer is
It is an object of the present invention to provide a wafer processing apparatus that can efficiently shape a circular shape having a constant diameter with a table device.

[0009]

In order to achieve the above-mentioned object, the present invention integrally forms a wafer holding portion for holding a wafer, a hollowing processing portion, a first chamfering processing portion and a second chamfering processing portion. Grinding wheel block, and the grinding wheel block, a plurality of grinding wheel blocks are arranged on the same circumference, and is composed of a grinding wheel block holding section slidably supported in the radial direction, the wafer holding section and the grinding wheel While relatively rotating the block holding part on the same axis,
The wafer holding part and the grindstone block holding part are relatively brought close to each other, the cut-out processing part of the grindstone block is brought into contact with the surface of the wafer to cut the wafer in a circular shape, and the peripheral edge of the wafer is cut into the circular shape. One side is brought into contact with the first chamfering portion to chamfer one side of the peripheral edge of the wafer, and the other side of the peripheral edge of the wafer is brought into contact with the second chamfering portion. The chamfering process is performed on the other side of the peripheral edge of the wafer.

According to the present invention, first, the wafer holding portion and the grindstone block holding portion are relatively rotated coaxially with each other, and the wafer holding portion and the grindstone block holding portion are brought relatively close to each other to move the grindstone block. The hollowed portion is brought into contact with the surface of the wafer. As a result, the wafer is ground by the hollowed portion of the grindstone block and hollowed into a circle. Next, one side of the peripheral edge of the rounded-out wafer is brought into contact with the first chamfered portion. As a result, one side of the peripheral edge of the wafer is ground by the first chamfering portion to be chamfered. Next, the grindstone block is slid and moved, and the wafer holding section and the grindstone block holding section are relatively moved to position the other side of the peripheral edge of the wafer on the second chamfering section side. Then, the other side of the peripheral edge of the wafer is brought into contact with the second chamfered portion. As a result, the other side of the peripheral edge of the wafer is ground and chamfered by the second chamfering portion. Through the series of operations described above, a non-circular wafer or a wafer having a different outer diameter is shaped into a circular wafer having a constant diameter.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a wafer processing apparatus according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a sectional view of a first embodiment of a wafer processing apparatus according to the present invention. As shown in the figure, the wafer processing apparatus 10 mainly includes a wafer holder 12, a grindstone block holder 14, and grindstone blocks 16, 16, ....

The wafer holder 12 is provided with a wafer 18
Having a wafer table 20 for vacuum adsorbing and holding
The wafer table 20 is installed on a base (not shown). The grindstone block holding portion 14 has a turntable 26 that holds the grindstone blocks 16, 16, .... The turntable 26 is provided coaxially to face the wafer table 20, is rotated by a motor (not shown), and is driven by an elevating device (not shown) to move vertically in the figure.

As shown in FIG. 2, the turntable 2 is provided.
Guide grooves 28, 28, ... Are bored at an interval of 90 ° along the radial direction of the turntable 26 on the lower surface 26A of No. 6. Inside each guide groove 28, a screw rod 30 is arranged along the guide groove 28, and the screw rod 30 is rotatably supported in the vicinity of both ends at both ends of the guide groove 28. As shown in FIG. 1, a driven worm gear 32 is fixed to one end of the screw rod 30.
2 is screwed into a drive worm gear 34 provided in the center of the inside of the turntable 26. The drive worm gear 34 is connected to a spindle 36 which is vertically arranged with respect to the turntable 26, and the spindle 36 is connected to a motor (not shown) capable of rotating in the forward and reverse directions.

On the other hand, a slider 38 that slides along the guide groove 28 is fitted in each of the guide grooves 28 on the same circumference. A nut portion 38A is formed on the slider 38, and the nut portion 38A is connected to the screw rod 30 arranged in the guide groove 28. Therefore, each of the sliders 38 slides in the guide groove 28 by the same amount of movement by driving the motor to rotate the driving worm gear 34 and the driven worm gear 32. As a result, the four sliders 38
Are always kept on the same circumference.

The grindstone block 16 is detachably attached to each slider 38, and a bolt 40 is attached to the slider 38.
It is fixed at. The grindstone block 16 includes a base portion 16A, a chamfering portion 16B and a hollowing portion 16C.
Are integrally formed. The base portion 16A
Is formed in a rectangular shape and has a through hole 16a through which the bolt 40 passes. The base portion 16A is formed by fitting the base portion 16A into a mounting groove 38B formed on the lower surface of the slider 38, and screwing a bolt passing through the through hole 16a into a bolt hole 38C formed in the mounting groove 38B. By doing so, the positioning is fixed.

The chamfered portion 16B is formed integrally with the lower portion of the base portion 16A. The chamfered portion 16B has a protrusion 16b having a trapezoidal cross section on the inner peripheral side, and when the grindstone block 16 is rotated, the protrusion 1
The lower inclined surface 16b ₁ (first chamfering portion) of 6b is brought into contact with the upper side of the peripheral edge of the wafer 18, so that the upper side of the peripheral edge of the wafer 18 is chamfered. In addition, while the grindstone block 16 is rotated, the upper inclined surface 16b ₂ (second chamfer processing portion) of the protrusion 16b is moved to the wafer 18
The chamfer on the lower side of the peripheral edge of the wafer 18 is processed by contacting the lower side of the peripheral edge of the wafer 18.

The hollowed-out portion 16C is integrally formed in the lower portion of the chamfered portion 16B. The hollowed-out portion 16C is formed in an arcuate wedge shape, and the wafer 18 is hollowed out in a circular shape by bringing the hollowed-out portion 16C into contact with the surface of the wafer 18 while the grindstone block 16 is rotated. . Since the hollowing process of the wafer 18 is performed by rough grinding and the chamfering process and the outer diameter process are performed by the finishing process, for example, the grain size of the tip 16c of the hollowing process part 16C is about # 300, and the grain size of the chamfering process part 16B is. Use the one of about # 800.

The operation of the first embodiment of the wafer processing apparatus according to the present invention constructed as described above is as follows. First, the wafer 18 is placed on the wafer table 20 and vacuum-adsorbed and fixed. Since the thickness and the outer diameter of the wafer 18 are defined by the standard, the whetstone blocks 16, 16, ... The diameter D formed by 16C, 16C, ... Is set.

Next, a motor (not shown) of the turntable 26 is driven to rotate the turntable 26, and an elevating device (not shown) for the turntable 26 is driven to turn the turntable 26 into a wafer table. Lower towards 20. As a result, the four grindstone blocks descend while rotating on the same circumference. Turntable 2
6 descends toward the wafer table 20, whereby the tip 1 of the hollowed-out portion 16C of the grindstone block 16 is cut.
6c contacts the surface of the wafer 18. As a result, the surface of the wafer 18 is ground into a circular shape. Then, when the turntable 26 is further lowered, the hollowing processing unit 1
The tip 16c of 6C penetrates to the back surface of the wafer 18, and the wafer 18 is hollowed out in a circular shape (see FIG. 3A, FIG. 3A is a sectional view taken along line BB in FIG. 1). On the other hand, the outer frame portion 18 ′ of the hollowed-out wafer 18 is the wafer table 2
Fall below 0.

After the wafer 18 is hollowed out in a circular shape, the turntable 26 is further lowered,
The upper part of the peripheral edge of the whetstone contacts the lower inclined surface 16b ₁ (first chamfering portion) of the protrusion 16b of the grindstone block 16.
Then, when the turntable 26 is further lowered by a predetermined amount, the lower inclined surface 16b ₁ is ground and the wafer 1
The upper part of the peripheral edge of 8 is chamfered (see FIG. 3B).

After chamfering the upper part of the peripheral edge of the wafer 18, a drive motor (not shown) for the drive worm gear 34.
To increase the diameter of the grindstone block 16. Then, the turntable 26 is lowered by a predetermined amount to move the wafer 18 onto the upper inclined surface 16b ₂ of the protrusion 16b of the grindstone block 16.
It is positioned above (the second chamfering portion), and then the drive motor of the drive worm gear 34 is driven again to return the diameter of the grindstone block 16 to the initial setting value D.

When the turntable 26 is raised in the above state, the lower part of the peripheral edge of the wafer 18 is moved to the grindstone block 16
The upper inclined surface 16b ₂ (second chamfered portion) of the protruding portion 16b is brought into contact. And further turntable 26
By raising a predetermined amount, the upper inclined surface 16b
_After being ground to ₂ , the lower part of the peripheral edge of the wafer 18 is chamfered (see FIG. 3C).

By chamfering the lower portion of the peripheral edge of the wafer 18, a series of wafer shaping operations are completed, and a drive motor (not shown) for the drive worm gear 34.
To increase the diameter of the grindstone block 16 and raise the turntable 26 to remove the wafer 18 from the wafer table 20. As described above, according to the wafer processing apparatus 10 of the first embodiment, it is possible to perform the shaping process of the wafer 18 which has been conventionally performed by using the two processing machines of the outer diameter grinding machine and the chamfering machine. Can be done with a single device. As a result, it is possible to reduce the facility cost and easily perform maintenance management. In addition, the device can be made compact.

Further, since a series of shaping work can be continuously processed by one device, the work process is shortened and the productivity is improved as compared with the conventional case. Further, in the wafer processing apparatus 10 according to the present embodiment, even when a non-circular wafer is shaped into a circle, the wafer is continuously ground to form a circle, so that the conventional outer diameter grinding process for performing intermittent grinding is performed. Compared with the machine, the damage of the wafer is less likely to occur and the load on the grindstone is reduced.

FIG. 4 is a sectional view of a second embodiment of the wafer processing apparatus according to the present invention. The same members and the same devices as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In the first embodiment,
A protrusion 16b having a trapezoidal cross section was formed on the chamfered portion 16B of the grindstone block 16, and the lower inclined surface 16b ₁ and the upper inclined surface 16b ₂ were used as the first chamfered portion and the second chamfered portion, respectively. . In the second embodiment,
A recess 16b ′ having a trapezoidal cross section is formed in the chamfered portion 16B of the grindstone block 16, and the lower inclined surface 16b ₁ ′ is used as the first chamfered portion and the upper inclined surface 16b ₂ ′ is used as the second chamfered portion. To do.

According to the wafer processing apparatus of the second embodiment configured as described above, first, as in the case of the first embodiment, the hollowed-out portion 1 of the grindstone block 16 is first processed.
Carry out hollowing at 6C. Next, turntable 26
Are lowered to position the wafer 18 in the middle between the lower inclined surface b ₁ ′ and the upper inclined surface b ₂ ′ of the chamfered portion 16B. Then, the drive motor (not shown) of the drive worm gear 34 is driven to reduce the diameter of the grindstone block 16 by a predetermined amount.

After the wafer 18 is positioned midway between the lower inclined surface b ₁ ′ and the upper inclined surface b ₂ ′ of the chamfered portion 16B, the turntable 26 is raised by a predetermined amount so that the lower portion of the peripheral edge of the wafer 18 is removed. , The protrusion 16 of the grindstone block 16
It contacts the lower inclined surface 16b ₁ (first chamfered portion) of b. Then, when the turntable 26 is further raised by a predetermined amount, the lower inclined surface 16b ₁ is ground, and the lower portion of the peripheral edge of the wafer 18 is chamfered.

After chamfering the lower portion of the peripheral edge of the wafer 18, the turntable 26 is processed by a predetermined amount, and the upper portion of the peripheral edge of the wafer 18 is projected onto the protrusion 1 of the grindstone block 16.
The upper inclined surface 16b _{2 of} 6b (the second chamfered portion) is abutted. Then, when the turntable 26 is further lowered by a predetermined amount, the upper inclined surface 16b ₂ is ground and the upper portion of the peripheral edge of the wafer 18 is chamfered.

As described above, the wafer processing apparatus of the second embodiment, like the wafer processing apparatus of the first embodiment, continuously processes a series of shaping operations by one apparatus. Therefore, the same effect as that of the first embodiment can be obtained. In this embodiment, the grindstone block 16 side is rotated, but the wafer 18 side may be rotated, or both may be rotated. Similarly, an elevating mechanism may be provided on the wafer 18 side.

In the first embodiment, the projection 16b of the grindstone block 16 has a trapezoidal cross section, but may have a triangular cross section. Further, the chamfering processing portion 16B is made to have a shape corresponding to the chamfering shape of the wafer 18 (for example, a recess having a semicircular cross section is formed on the inner peripheral side of the chamfering processing portion 16B), and the chamfering processing is performed by the total shaping. It may be performed. At this time, the control of the lateral feed amount is performed by controlling the motor that drives the drive worm gear 34.

Further, as shown in FIG. 5, a notched portion 42 may be added so that notching can be performed simultaneously with shaping. That is, the notch grinding stone 44 is rotatably provided at the tip of the arm 46, and the arm 46 is supported so as to be movable back and forth with respect to the wafer table 20. Then, the notch grinding stone 44
While rotating the arm 46, the arm 46 is moved to the wafer table 20.
Notch grinding stone 44 by advancing toward
Is brought into contact with the edge of the wafer 18 to process the notch 18N of the wafer 18.

The orientation flat processing may be performed instead of the notch processing. In this way, by adding the notch processing section 42 or the orientation flat processing section, the production efficiency of the wafer 18 is further improved.

[0033]

As described above, according to the present invention,
Since the wafer shaping process can be performed by one device, the facility cost can be reduced and the maintenance management can be easily performed. In addition, the device can be made compact. Further, since a series of shaping work can be continuously processed by one device, the work process is shortened and productivity is improved as compared with the conventional one.

Further, since the wafer is continuously ground and shaped into a circular shape, compared with the conventional processing machine that performs intermittent grinding,
Wafers are less likely to be damaged, and the load on the grindstone is low.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of a wafer processing apparatus according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG. 1;

3 (a) to 3 (c) are explanatory views for explaining the operation of the first embodiment of the wafer processing apparatus according to the present invention.

FIG. 4 is a sectional view of a second embodiment of a wafer processing apparatus according to the present invention.

FIG. 5 is an explanatory view of another embodiment of the wafer processing apparatus according to the present invention.

FIG. 6 is a perspective view of an ingot shape generated when GaAs is crystal-grown by the HB method.

FIG. 7 is a perspective view of an ingot shape generated when GaAs is crystal-grown by the CZ method.

FIG. 8 is an explanatory diagram (GaA) for explaining a conventional shaping method.
(When shaping an s-wafer (HB method))

FIG. 9 is an explanatory view for explaining a conventional shaping method (when shaping a mis-cut Si wafer).

[Explanation of symbols]

10 ... wafer processing apparatus 12 ... wafer holder 14 ... grinding block retaining portion 16 ... grinding block 16A ... base portion 16B ... chamfered portion 16C ... hollowing processing unit 16b ₁ ... lower inclined surface (first chamfered portions) 16b ₂ ... upper inclined surface (second chamfered portion) 16b ₁ '... lower inclined surface (first chamfered portions) 16b _2' ... upper inclined surface (second chamfered portion) 18 ... wafer 20 ... wafer table 26 … Turntable 38… Slider

Claims (1)

[Claims] 1. A grindstone block integrally formed with a wafer holding part for holding a wafer, a hollowing part, a first chamfering part and a second chamfering part, and the grindstone block on the same circumference. And a grindstone block holding portion slidably supported in the radial direction, and, while relatively rotating the wafer holding portion and the grindstone block holding portion coaxially, The wafer holding portion and the grindstone block holding portion are relatively close to each other, and the wafer is cut into a circular shape by bringing the hollowed-out portion of the grindstone block into contact with the surface of the wafer,
The one side of the peripheral edge of the wafer cut out in the circular shape is the first
The chamfering portion of the wafer to chamfer one side of the peripheral edge of the wafer, and the other side of the peripheral edge of the wafer to the second chamfering portion to contact the other side of the peripheral edge of the wafer. A wafer processing apparatus, which performs the chamfering process.