JPH06143132A - Holding chuck for work-holding mechanism - Google Patents

Abstract

PURPOSE:To hold even a work whose edge surface projects, as it is improve the working efficiency, and obviate the necessity of centering work, by allowing the shape of the edge surface of a holding chuck to gradually projects as departing in the radial direction from the revolution center axis and forming a space part in the center axis region. CONSTITUTION:A work holding chuck 1 is formed so as to nearly coincide with the shape of the projection at the center part on the edge surface of a work 4, and the work is held so that the most projecting part on the edge surface of the work is positioned at the center space part 2 of the chuck. In particular, when the work 4 is a semiconductor single crystal manufactured through the pulling-up method or floating region method, the work has a projection part 12 having a conical shape on both the edge surfaces, and in the holding work, a crystal rod is supported, allowing the chuck 1 on side to grip the single crystal projection part 12, and then the other projection part 12 is gripped by the other chuck 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chuck shape of a holding portion for holding a workpiece, a so-called work, in a grinding apparatus for grinding the surface of a metal ingot or a semiconductor crystal ingot, and more particularly to a convex portion at the center of the end face. By using a chuck having a cross-sectional shape that substantially conforms to the cross-sectional shape of the center portion of the end surface of the workpiece having the above, a technique for eliminating the work centering step is provided.

[0002]

2. Description of the Related Art Conventionally, various techniques for grinding a metal ingot or a semiconductor crystal into a cylindrical shape have been proposed and used. For example, that disclosed in Japanese Examined Patent Publication No. 59-29386 is a typical three-dimensional grinding technique.

In recent years, the diameter of semiconductor single crystals produced by, for example, a pulling method has been increased in order to increase the area efficiency of semiconductor chips on a wafer, and the product weight has already been 40%.
It even exceeds kg. In the case of a single crystal manufactured by the floating zone method or the pulling method, the cross-sectional shape of its end surface is substantially conical, and it is necessary to drop both end surfaces in order to grind it into a cylindrical shape.

[0004]

That is, in the centering work prior to grinding, "scribing" is performed in advance to form center holes on both end faces so that the center holes are aligned with the tips of the main shaft and the core pushing shaft. The work is done while supporting it with hands. However, in this case, it is difficult to work with a particularly heavy object and there is a safety problem. In order to solve such a problem, for example, Japanese Utility Model Publication No. 60-29442 discloses a device for eliminating a trouble caused by manpower by holding a work on a pedestal operated by hydraulic pressure and working. This is also the same as in the prior art in that both ends of the work are vertically cut and then sandwiched. Therefore,
Inevitably, an extra step of cutting off the end face of the work is required.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to eliminate the above-mentioned extra step, and holds a work having a convex portion at the center of the end face and grinds the side face portion while rotating the work. In the holding chuck used in the work holding mechanism of the machine, the end surface shape gradually projects as it moves away from the rotation center axis in the radial direction, that is, it projects toward the work side, and there is a space in the center axis region. It is characterized by having done.

Further, a structure is adopted in which this chuck is concentrically slidably divided into two inside and outside in the direction perpendicular to the rotation axis, and the inner chuck is pressed against the work side by a pressing mechanism such as a spring or a cylinder. You can also

Further, if a cushioning material is provided at the tip, the contact area with the work can be increased.

[0008]

The chuck for holding a work according to the present invention is formed so as to substantially match the shape of the protrusion at the center of the end face of the work.
The most projecting portion of the work end face is positioned and held in the central space of the chuck. In particular, when the work is a semiconductor single crystal manufactured by the pulling method or the floating zone method, it has conical projections on both end surfaces,
The operation for holding is to temporarily hold the convex portion of the single crystal on one chuck and support the crystal rod, and then hold the other convex portion on the other chuck.

FIG. 1 shows a work holding chuck 1 according to the present invention.
FIG.

As shown in the figure, the chuck 1 has a cross-sectional shape in which a space 2 is formed in the vicinity of the central axis of rotation and an end face 3 is formed.
Gradually projects away from the center in the radial direction,
It forms an inclined surface that is inclined toward the central axis of rotation. That is, the space portion 2 is formed so as to substantially follow the shape of the end surface convex portion of the ingot 4, and the space portion 2 escapes the end surface protruding portion tip of the held ingot. The other end of the chuck 1 is connected to a pressing mechanism (not shown) and presses the ingot 4 from the left and right. The chuck 1 may have a cylindrical shape, but may have a shape like arms arranged at regular intervals in the circumferential direction.

FIG. 2 shows a cross section of the holding chuck of the second invention.

The chuck 1 is concentrically divided into an inner chuck 5 and an outer chuck 6, and the inner chuck is configured to be slidable with respect to the outer chuck in parallel to the central axis of rotation, and the inner chuck outer wall. The guide projection 7 provided on the upper side engages with the guide groove 8 formed in the outer inner wall to limit the sliding range. Further, the inner chuck is pressed in the ingot direction by the compression spring 10 provided on the base portion 9. Of course, this compression spring can be replaced by something like a cylinder.

In this way, the held ingot is rotated together with the chuck by a drive mechanism (not shown) connected to the holding mechanism, and the outer periphery thereof is ground by a grinding wheel. FIG. 3 shows a state of grinding.

Next, the present invention will be described in more detail with reference to examples.

[0015]

Embodiment 1 An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a chuck 1 according to an embodiment of the present invention.
The figure shows a state in which a silicon single crystal ingot is held.

The chuck shape is cylindrical and the end face 3 is
An opening is formed and a slope is formed along the end face shape of the ingot. Since the end face shape of the ingot is slightly different on the top side and the bottom side, different chuck end face shapes are used. Although the one shown is for the top side, the slope of the slope is 6 at the portion indicated by the symbol A.
It is 0 degree and 40 degrees at the portion indicated by the symbol B. The material of the chuck is SK, and the inner diameter of the part that contacts the space 2 is 30 m.
m, the thickness of the chuck is 10 mm. The space portion 2 escapes the end surface convex portion of the silicon ingot. Chuck 1
Is pressed against the ingot by a pressing mechanism (not shown). An external grinding machine equipped with a work holding chuck according to an embodiment of the present invention shown in FIG.
The silicon single crystal was ground.

A silicon single crystal ingot pulled up by the CZ method, a diameter of 210 mm and a length of 1200 mm was held as it was by a holding chuck. After mounting, hold chuck 1
While rotating at 0 rpm, the outer diameter of the ingot was ground by a rotating grindstone 11 to a diameter of 10 mm. The progress speed of the grindstone is
It is 3 cm / min. There was no misalignment of the rotating shaft.
The time required from installation of ingot to completion of grinding is 60
It was a minute.

This saves 50% of the time compared to using a grinding machine with a conventional holding chuck. This is because, in order to attach the ingot to the conventional chuck holding mechanism, a step of cutting off the end portion of the ingot and a step of centering are required. Work efficiency is improved. Since the ingot is rotationally symmetric with respect to the convex portion 12,
When the chuck is held by the holding chuck of the present invention, the chuck rotation axis and the ingot center axis coincide with each other, so that centering is not necessary.

[0020]

Embodiment 2 FIG. 2 shows an embodiment of the holding chuck of the second invention. This is a state where the chuck 1 holds the silicon single crystal ingot 4.

The chuck has a cylindrical shape similar to that of the first embodiment, but is concentrically divided into two chucks, an inner chuck and an outer chuck, and the inner chuck has a structure capable of sliding with respect to the outer chuck. Also, the slope of the end surface of the inner chuck is
The inclination angle is larger than that of the outer chuck. The end angle of the inner chuck is 60 degrees and that of the outer chuck is 40 degrees.
It is degree. This is to make the shape of the convex portion of the end surface of the ingot follow the shape of the convex portion as much as possible, so that the grip can be reliably performed. Further, a compression spring 10 is provided on the base portion 9 of the inner chuck to elastically press the inner chuck in the gripping ingot direction. However, the sliding range is limited by the action of the guide protrusion 7 and the guide groove 8 provided between the inner and outer chucks.

The total thickness of the chuck is 30 mm inside and outside.
Is.

When holding the ingot on the chuck, the inner chuck is pushed by the ingot and slides inward. Therefore, even with an ingot having a convex portion having a slightly different inclination, for example, one chuck can cope with the movability of the inner chuck. Since the shock to the ingot is less than that of the fixed chuck, no damage is required.

Using a grinding machine equipped with the holding chuck of the present invention, the outer shape of a silicon single crystal was ground. The conditions and results were the same as in Example 1.

[0025]

[Effect] According to the holding chuck of the first invention, it is possible to hold a work, such as a semiconductor single crystal ingot, having a protruding end surface as it is, so that the step of cutting off the end portion as in the conventional case can be performed. It becomes unnecessary and work efficiency improves.
Further, since centering work is not necessary, the time and work risk involved can be reduced.

According to the holding chuck having two chucks, the inner chuck and the inner chuck, the inner chuck slides inward, so that the inclination of the convex end surface is slightly different. Since it can be applied to ingots, there is almost no need to replace the chuck.

Further, in the case where the chuck end surface is provided with the cushioning material, the gripping force increases due to friction, and therefore it is stable even during vibration. Also, the ingot is not damaged.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a holding chuck of the present invention.

FIG. 2 is a vertical sectional view showing an embodiment of a second invention of a holding chuck.

FIG. 3 is a view showing a state in which the silicon single crystal held by the holding chuck of the present invention is being ground.

FIG. 4 is a diagram showing a state in which a workpiece is externally ground using a conventional holding chuck.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 chuck 2 space part 3 end surface 4 ingot 5 inner chuck 6 outer chuck 7 guide protrusion 8 guide groove 9 base 10 compression spring 11 rotating grindstone 12 convex part

Claims (5)

[Claims] 1. A work having a convex portion at the center of the end face is held,
In a holding chuck used in a work holding mechanism of a grinding device that grinds its side surface while rotating, the end surface shape gradually projects away from the rotation center axis in the radial direction, and there is a space in the center axis area. A chuck for holding a work, which has a portion. 2. The holding chuck is concentrically divided into two inside and outside so as to be slidable relative to each other in the direction perpendicular to the rotation axis, and the inside chuck is configured to be elastically ejected toward the work side by a pressing mechanism. A chuck for holding a work according to claim 1. 3. The work holding chuck according to claim 2, wherein the pressing mechanism is a compression spring. 4. The work holding chuck according to claim 2, wherein the pressing mechanism is a cylinder. 5. The work holding chuck according to claim 1, wherein a cushioning material is provided at a tip end portion of the chuck.