JPH0478084B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method and apparatus for cutting columnar materials, and in particular, to cutting columnar materials (hereinafter referred to as ingots) such as silicon, which is a raw material for semiconductor device manufacturing, using a rotating blade. The present invention relates to a method and apparatus for cutting columnar material.

[Conventional technology]

Ingots such as silicon used in semiconductor devices are brittle, so when the ingot is cut into thin pieces with a rotating blade, the ingots crack and chip just before the cutting is completed, resulting in the ingots being separated. As a result, the outer periphery of the wafer cut into thin pieces is damaged, resulting in a problem in that the number of semiconductor elements obtained from one wafer is significantly reduced.

In order to solve this problem, a waste material made of carbon or the like (hereinafter referred to as the slice base) was attached to a part of the side of the ingot in the longitudinal direction by gluing, etc., and cutting was done by gluing this slice base. A cutting method is used in which cutting is performed from the side facing the surface and the slice base is cut last (see, for example, Japanese Patent Application Laid-Open No. 61-65749).

[Problem that the invention seeks to solve]

According to the above cutting method, the problem of missing ingots and wafers is temporarily resolved, but it requires work such as preparing and attaching the slice base in advance, and removing the slice base from the wafer after cutting. Also, it is necessary to select a slicing base made of a material that does not adversely affect the cutting edge of the blade.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method and apparatus for cutting columnar material that does not require the addition of a slice base and does not cause defects such as cracks during cutting. .

[Means for solving problems]

In order to achieve the above object, the present invention fixes the base end side of the columnar material, and arranges a plurality of cylinders facing the cut side end surface of the columnar material.
A suction pad that performs vacuum suction via a spherical bearing is disposed on the piston of each cylinder, and before the start of cutting the columnar material, the plurality of cylinders are operated to press each suction pad against the end surface of the columnar material; After that, the pressing force of the suction pads by the cylinders is released, and the pistons of each cylinder are fixed so that they cannot move forward or backward while each suction pad is adsorbed to the end surface of the columnar material, and the columnar material is moved by the rotating blade. It is characterized in that it can be cut with a twist.

[Effect]

According to the present invention, during cutting, the end face of the columnar material on the cutting side is fixed by suction using the suction pad or the like. Here, the end face of the columnar material on the cut side is not necessarily parallel or flat. Therefore, in the present invention, the suction pad is supported by a spherical bearing so that it can swing, and a plurality of suction pads are provided and each suction pad can be moved forward and backward by a cylinder, and each suction pad is made of columnar material. It is made to fit the end face of the cut side without any gaps. In addition, when placing the suction pad on the end surface, the suction pad is pressed against the end surface by a cylinder, but once the suction pad is pressed, the pressure is Release power. The piston of each cylinder is fixed so that it cannot move forward or backward with each suction pad along the end surface. Therefore, each suction pad adheres to the cut end surface of the columnar material without any gaps, and uses its suction force to suction and hold the end surface, but there is no pressing force on the end surface from the suction pad side that changes the end surface. Since no tension or tensile force is applied, cracks will not occur until the cutting is completed.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the method and apparatus for cutting columnar material according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a perspective view of a cutting device for columnar material according to the present invention. This device includes an inner peripheral blade type blade 12 having a blade part 12A formed on the inner peripheral edge for cutting the columnar material (ingot) 10, a collection conveyor 16 for transporting the cut wafers to a wafer storage cassette 14, etc. A support 22 includes a main body 18 and an indexing slider 20 that fixes the proximal end of the ingot 10 and moves the ingot 10 in the vertical direction. The cutting table 28 includes an arm 26 equipped with a collection tray 24 that later transfers the wafer to the collection conveyor 16.

As shown in FIG. 2, the internal blade type blade 12 is fixed to the upper end of the rotating body 19 and is configured to rotate at high speed, so that the cutting feed table 28, that is, the ingot 10 moves in the direction of arrow A. The ingot 10 is cut. Further, the thickness of the wafer cut in this manner is determined by the amount by which the ingot 10 is fed downward by the indexing slider 20.

On the other hand, during the above-mentioned cutting, the collection tray 24 is used to hold the ingot 1 so that the wafer will not be cracked until the cutting is completed.
The cutting side end face of 0 is held by suction and moved together with the cutting feed table 28. Note that the details of this collection tray 24 will be described later. Also, after cutting,
The collection tray 24 is rotated 180 degrees from the state shown in FIG. 2, and then the arm 26 is raised and the wafer is delivered to the collection conveyor 16 by a wafer unloader device (not shown).

Next, the collection tray 24 will be explained in detail.

3 is a plan view of the recovery tray 24, FIG. 4 is a sectional view taken along the line AA in FIG. 3, and FIG. 5 is a sectional view taken along the line BB in FIG. 3. This collection tray 24
As mentioned above, the wafer has the function of suctioning and holding the cutting side end face of the ingot 10 during cutting, and as shown in FIG. Correspondingly, they are arranged at equal intervals on the same circumference so as to be evenly located over the entire surface of the wafer.

FIG. 8 is an enlarged view of the vacuum chuck 30 surrounded by the dashed line in FIG. This vacuum chuck 30 mainly consists of a cylinder 31 housed and fixed in the collection tray 24, and a pad support ball 32 at one end.
It consists of a piston 34 having a vacuum rod 33 embedded therein, and a suction pad 35 supported by the pad support ball 32.

The pad support ball 32 consists of a sphere with a vacuum hole formed in the center, and the suction pad 35 has two
The pad support ball 32 is attached to the pad support ball 32 by sandwiching the pad support ball 32 between two conical members 35B and 35C. That is, a spherical bearing is constructed between the pad support ball 32 and the suction pad 35, so that the suction pad 35 can tilt in all directions. FIG. 9 shows a state in which the suction pad 35 is tilted at an angle of 5°.

A set screw 37 and a clamp pin 56 are fitted into the outer circumference of the cylinder 31.
is fixed to the collecting tray 24, and the piston 34 can be clamped by the pressing force of a clamp pin 56, which will be described later.

The piston 34 is formed with a vacuum hole 34A that communicates with the vacuum rod 33, and the vacuum holes 34A of each piston 34 communicate with each other through a vacuum tube 34B as shown in FIG. The terminal end is formed in the vacuum hole 34C (Fig. 5,
and FIG. 6, which is a sectional view taken along line CC in FIG. 5), and communicates with a vacuum hole (not shown) on the arm 26 side. Further, a vent hole 34D is formed in the piston 34 to keep the pressure at the top and bottom of the piston the same, thereby preventing the occurrence of hysteresis in the suction pad 35 due to minute air leaks from the spherical bearing. That is, when a minute air leak occurs in the spherical bearing part in FIG. 8, negative pressure is generated in the X part, and as a result, X<Y (atmospheric pressure), so the piston 34 has an X part and a Y part. The upward force F will move due to the differential pressure of
The vent hole 34D can prevent a pressure difference from occurring between the X section and the Y section.

Further, the tip of the suction pad 35 is a porous pad 35A (for example,
SUS material) is provided, and when the wafer is picked up,
The suction force prevents the wafer from deforming. Furthermore, a bellofram 36 is disposed between the suction pad 35 and the cylinder 31. still,
39, 40, 41 are O-rings, and 42A is a packing.

Next, the operation of the vacuum chuck 30 having the above structure will be explained.

First, before starting cutting of the ingot 10, the collection tray 24 is moved so that the six vacuum chucks 30 face the end face of the ingot 10 on the cutting side. Then, after stopping the movement of the collection tray 24,
Turn on the vacuum pump (not shown) and apply a vacuum to the tip of the suction pad via the arm 26, the vacuum hole 34C of the collecting tray 24, the vacuum tube 34B, the vacuum hole 34A of the piston 34, the vacuum rod 33, and the support ball 32. In addition to generating pressure, an air supply hole 42 is provided at the bottom of the piston 34.
(Fig. 3) and supply compressed air to the piston 34.
to rise. Note that FIGS. 8 and 9 show the state in which the piston 34 has risen to the uppermost end.

While the piston 34 is rising, the six suction pads 35 rise and tilt according to the shape of the ingot end surface, and adsorb the ingot end surface while being in contact with the ingot end surface without any gaps. In this state, the entire collecting tray and the arm 26 supporting the collecting tray 24 are deflected due to the reaction force from the end face of the ingot against the pressing force of the piston 34.

In this state, the compressed air supplied to the lower end side of the piston 34 is released to the atmosphere. As a result, the collection tray 2
The deflection of the 4th grade is eliminated and there is no distortion.
That is, the suction pad 34 is stuck to the ingot end face only by suction force, and no pressing force or tensile force acts on the ingot end face.

After that, the cylinder 3 is clamped by the clamp pin 56.
1 and fix the piston 34.

As mentioned above, since the cut side end face of the ingot 10 is fixed, the cut wafer does not wobble during cutting, and since no pressing force is applied from the collecting tray 24 side, the wafer is cut without chipping. can be completed. In addition, since the suction pad 35 is configured to be able to swing,
There is a concern that the wafer may wobble during cutting, but since each suction pad 35 is prevented from moving forward or backward, and a large number of suction pads 35 are evenly distributed on the suction end surface, the wafer cannot be fixed as a whole. , the wafer does not wobble. Further, a porous pad 35A is provided at the upper end of the suction pad 35, and the suction surface thereof is flat, so that stress due to suction force does not act on the wafer.

Next, a clamp device for fixing each piston 34 will be explained.

FIG. 10 is an enlarged view of the clamp device 50 surrounded by the dashed line in FIG. 4, and FIG. 11 is a sectional view taken along line DD in FIG. 10. This clamp device 50 mainly includes a cylinder portion 51 formed in the center of the collection tray 24, a hollow first piston 52 that slides inside this cylinder portion 51, and a first piston 52 that slides inside this first piston 52. a second piston 53;
The first piston 52 and the second piston 53
a first ring 54 and a second ring 55, which are respectively pressed by the cylinder part 51, and six clamp pins 56 which slidably penetrate around the cylinder part 51 and are arranged radially at equal intervals. , a first plate 57 disposed between the first ring 54 and the three clamps 56, and a first plate 57 disposed between the second ring 55 and the other three clamp pins 56. 2
It is composed of a plate 58.

A stopper 60 is provided at the lower end of the second piston 53.
is disposed, the second ring 55 is disposed between the second piston 53 and the stopper 60, and the first ring 54 is disposed between the first piston 52 and the stopper 60. There is.

A first plate 57 and a second plate 5 are arranged around the first ring 54 and the second ring 55.
Grooves 54A and 55A are formed for hooking one end of the clamp pin 56, and similarly, a groove 56A for hooking the other ends of the first plate 57 and the second plate 58 is formed at the rear end of the clamp pin 56. It is formed.
Further, as described above, the tips of the six clamp pins 56 are fitted into the outer periphery of each cylinder 31 of the six vacuum chucks 30 (FIGS. 11 and 6).
(see figure).

Note that a second plate 58 is attached to the first ring 54.
A hole 54B is formed for the piston to pass through, and gaskets 62 and 63 are provided between the cylinder portion 51 and the first piston 52 and between the first piston 52 and the second piston 53, respectively. ing.

Next, the operation of the clamp device 50 having the above configuration will be explained.

As mentioned above, the collection tray 24 holds the ingots 10.
When moved to a position opposite to the cut side end face of 6
Compressed air is supplied to the lower part of the piston 34 of each vacuum chuck 30 from the air supply hole 42 (FIG. 3), and at the same time, compressed air is supplied to the lower part of the first piston and the second piston 53 of the clamp device 50. Compressed air is also supplied.

As a result, the first piston 52 and the second piston 53 are pushed up, and at the same time, the stopper 60 connected to the second piston 53 is raised, so that the first ring 54 and the second ring 55 are pushed up.
is also pushed up. As these rings 54 and 55 rise, the ring hooking sides of the first plate 57 and second plate 58 are lifted, and as a result, the pressing force on the cylinder 31 by the clamp pin 56 is released, and the vacuum chuck 30 The piston 34 becomes slidable within the cylinder 31.

After that, as described above, after the ingot end face is attracted by the six vacuum chucks 30, the piston 34 of each vacuum chuck 30
are simultaneously fixed by the clamping device 50.

That is, when fixing the piston 34 of the vacuum chuck 30, the first piston 52 and the first piston of the clamp device 50 are fixed via the air supply hole 43 and the air supply path 43A (see FIGS. 3 and 5). 2
Compressed air is supplied to the upper part of the piston 53.
Note that the first piston 52 and the second piston 53
The lower part is open to the atmosphere.

As a result, the first piston 52 and the second piston 53 are each independently pushed down,
Press the first piston 54 and the second ring 55 downward. Then, the first ring 54 and the second ring 54
The rings 55 press six clamps 56 arranged radially through the first plate 57 and the second plate 58, respectively, and these clamp pins 56 press against each cylinder 31 of the six vacuum chucks 30. Clamp the piston 34 in each cylinder 31 by pressing on the side of the piston 34 in each cylinder 31.

Note that when the clamp is finished, the first plate 57
and the inclination of the second plate 58 approaches horizontal,
The amount of movement of the plates 57, 58 on the clamp pin latching side is minute compared to the amount of movement of the plates 57, 58 on the ring latching side, and a large pressing force acts on the clamp pin 56 due to this boosting mechanism. Further, the first piston 52, the first ring 54, the first plate 57 and the second piston 53, the second ring 55, and the second plate 57 each operate independently, and each has three clamps. Since it has a double structure in which the piston 34 of the vacuum chuck 30 is clamped via the pin 56, the clamping can be ensured.

〔Effect of the invention〕

As explained above, according to the method and apparatus for cutting columnar material according to the present invention, it is not necessary to attach the slice base to the columnar material with adhesive or the like, and the material cost of the slice base itself can be reduced. Adhesion and peeling (disposal) processes can be reduced. Furthermore, when holding the cut end face of the columnar material by suction, the suction pad can be applied to the end face without any gaps and in such a way that no unnecessary external force is applied to the end face from the suction pad side. No defects such as cracks will occur until the cutting is completed, even when cutting extremely thin wafers or particularly brittle materials such as GaAs.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a cutting device for columnar material according to the present invention, and FIG. 2 is a diagram used to explain a cutting method using the cutting device for columnar material according to the present invention.
FIG. 3 is a plan view of a collection tray used in the cutting apparatus for columnar material according to the present invention, and FIGS. 4 and 5 are sectional views taken along line A-A and B-B in FIG. 3, respectively.
6 is a sectional view taken along line C-C in FIG. 5, FIG. 7 is a diagram used to show the vacuum tubes etc. connected to each vacuum chuck, 9 and 9 are enlarged views of the vacuum chuck shown in FIG. 4, FIG. 10 is an enlarged view of the clamp device shown in FIG. 4, and FIG. 11 is an enlarged view of the vacuum chuck shown in FIG.
FIG. 2 is a cross-sectional view taken along line D-D in FIG. DESCRIPTION OF SYMBOLS 10... Column material (ingot), 12... Inner peripheral blade, 20... Index slider, 24... Collection plate, 26... Arm, 28... Cutting feed table, 3
0... Vacuum chuck, 31... Cylinder, 32
... Pad support ball, 34... Piston, 35... Suction pad, 35A... Porous pad, 50... Clamp device.

Claims (1)

[Scope of Claims] 1. The proximal end side of the columnar material is fixed, and a plurality of cylinders are arranged facing the cut side end surface of the columnar material, and the piston of each cylinder is connected via a spherical bearing. A suction pad that performs vacuum suction is provided, and before the start of cutting the columnar material, the plurality of cylinders are operated to press each suction pad against the end surface of the columnar material, and then the pressing force of the suction pad by the cylinder is applied. After being released, the piston of each cylinder is fixed so that it cannot move forward or backward with each suction pad adsorbed to the end surface of the columnar material, and the columnar material is cut by a rotating blade. How to cut columnar material. 2. A cutting device for columnar material that rotates a blade to cut a columnar material whose base end side is fixed, comprising: a plurality of cylinders disposed opposite to the cutting side end surface of the fixed columnar material; , a piston slidably disposed within each cylinder; a suction pad disposed on the piston via a spherical bearing; a reduced pressure suction means for generating suction force on the suction pad; and the plurality of pistons. and a clamping means for fixing each of the cylinders so that they cannot move forward or backward, and the piston of each cylinder is fixed with the suction pad adsorbed to the end surface of the columnar material. Device. 3. The apparatus for cutting columnar material according to claim 2, wherein the plurality of cylinders are air cylinders arranged on a movable collection tray. 4. The cutting device for columnar material according to claim 2, wherein a vacuum rod having a pad support ball is installed at one end of the piston, and the suction pad is supported by the pad support ball so as to be tiltable in all directions. . 5. The cutting device for columnar material according to claim 4, wherein a hole for a vacuum rod is formed in the center of the vacuum rod and the pad support ball. 6. The piston in which the vacuum rod is installed has a vacuum hole in the side of the piston that communicates with the hole of the vacuum rod, and each vacuum hole of the plurality of pistons communicates with each other through a vacuum tube. A cutting device for columnar materials. 7. The cutting device for columnar material according to claim 2, wherein a bellofram is disposed between the suction pad and the cylinder. 8. The cutting device for columnar material according to claim 7, wherein the piston has a vent hole formed therethrough to maintain the same pressure at the upper and lower portions of the piston. 9. The cutting device for columnar material according to claim 2, wherein the suction pad has a porous pad with a flat top end provided at its tip.