JPH0550422A - Cutting method by means of multiwire saw - Google Patents

Abstract

PURPOSE:To prevent crack and break from occurring on a surplus portion of the end of a work when a fragile material is cut by a multiwire saw. CONSTITUTION:A work 6 is fixed onto a steel base 9 mounted on a work push-up base of a wire saw through a dummy plate 8. A reinforcing member 13 is bonded to the end surface of the work 6 to cut the work 6. When a force is exerted outwardly on a surplus portion 6-2 of the end of the work during a cutting operation, said portion 6-2 is supported by the member 13. Consequently, even if the thickness of the surplus portion 6-2 on either end of the work 6 is made thin, crack and break will not occur on the portion 6-2 and the number of product wafers that can be obtained from one work 6 increases, resulting in lowered cutting cost and reduced material cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-wire saw for cutting brittle materials such as semiconductor materials and ceramics into a large number of thin wafers by wires and abrasive grains (hereinafter, simply referred to as "wire saw" for convenience of description), The present invention relates to a cutting method for preventing breakage of an object to be cut (hereinafter referred to as "workpiece") during cutting to reduce cutting cost and material cost.

[0002]

2. Description of the Related Art A wire saw presses a work against a row of wires having a predetermined pitch, and pours a working liquid containing abrasive grains (hereinafter referred to as "abrasive liquid") to move the wire and the work relative to each other.
It is a device that cuts a large number of wafers by a grinding action.
FIG. 4 shows an example of a cutting part of a general wire saw,
A wire row 5 having a predetermined pitch is formed by winding one wire 4 around a large number of ring-shaped grooves engraved at a predetermined pitch on the outer peripheral surfaces of three groove rollers 1, 2 and 3 rotatably held. Then, let this wire row travel back and forth or in one direction,
While the polishing liquid 7 is applied to the work 6, the work push-up base 10 is gradually raised and cut. A dummy plate 8 made of a brittle material such as ceramics or glass is adhered to the work 6, and the dummy plate 8 is adhered to a steel base 9 which is detachably attached to the work push-up base 10 with a tightening screw 11. Has been done.

FIGS. 5A and 5B show a state in which the wire array 5 is cut to near the center of the thickness of the dummy plate 8. FIG. 5A is a perspective view and FIG. 5B is a partially enlarged front view. At this stage, the work 6 is cut into the work surplus portions 6-2 at both ends and a large number of product wafers 6-1 having a predetermined width t ₁ . Abrasive grains are filled in the groove 12 formed by cutting the wire 4.
Here, as a method of collecting the wafer 6-1, for example, while the wire row 5 is traveling at a low speed, the work push-up base 10 is lowered to separate the wire row 5 and the work 6, and the fixing bolt 11 is used.
Can be removed by loosening the base 9 to remove the base 9 from the push-up base 10, and then the base 9 of the dummy plate 8 can be sequentially folded from the extra length portion 6-2 at one end.

[0004]

By the way, when trying to collect as many product wafers 6-1 as possible from one work 6, the thickness t ₂ of the extra length portions 6-2 at both ends is thin. Become.
When the work 6 is a brittle material and the product wafer 6-1 has a large cross-sectional area, if the t ₂ is thin, the extra length portion 6-2 may be broken during cutting. FIG. 6 shows forces acting in the thickness direction of the extra length portion 6-2 and the product wafer 6-1 during cutting. That is, in the part where the wire 4 is running, the abrasive grains in the groove 12 run along with the movement of the wire 4 and grind the work, so that the force f ₁ acts in the horizontal direction. Further, a horizontal force f ₂ acting on the side surface of the groove 12 as a resultant force of the pressure of the filled polishing liquid also acts. It is considered that f ₁ is constant regardless of the depth of the groove 12, but f ₂ increases as the groove 12 becomes deeper. Since both f ₁ and f ₂ act on both sides of the product wafer 6-1, the product wafer 6-1 is not cracked by f ₁ and f ₂ . On the other hand, since the extra length portion 6-2 receives f ₁ and f ₂ from only one side, the extra length portion 6-2 may be broken at the portion indicated by the arrow a in FIG. Once cracks occur, the groove 12 at the end
Since the pressure of the polishing liquid acting on the product wafer 6-1 at the edge becomes zero, the product wafer 6-1 at the edge has a force f from only one side.
You will receive ₂ . The product wafer by the f ₂ 6-
When cracks occur in No. 1, product wafers 6 are successively produced in a chain reaction.
-1 will crack and the damage will spread. Then, not only the product wafer 6-1 becomes uncollectible, but also the man-hours required for the cutting up to that point are wasted, and in some cases, the broken pieces of the work are scattered and the wire saw may be damaged. Incidentally, the crack as described above may occur not only in the multi-wire saw but also in the multi-blade saw,
This is a common problem when a large number of pieces are cut at the same time by using a polishing liquid.

In order to solve the above-mentioned problems in a multi-wire saw, the present invention is capable of collecting as many product wafers as possible from a single material work, even if the extra length of the end portion is thinned, while cutting. In addition, the present invention intends to propose a cutting method capable of cutting the surplus length portion and the product wafer without cracking.

[0006]

A cutting method using a multi-wire saw according to the present invention is a means for preventing cracking of a surplus length portion of a work due to an outward force acting on the surplus length portion during cutting. It aims to give a force that can counter the force in the direction to the end surface of the work, the gist of which is
It is a method of placing a reinforcing member on the end surface of the work and cutting it.
Further, it is a method in which a face plate provided so as to be separable at a position facing the end face of the work is brought into contact with the end face of the work to cut.

[0007]

The reinforcing member and the face plate are provided to prevent the surplus portion of the work from breaking outward during cutting. The reinforcing member is directly bonded to the work, or a dummy material bonded to the work, or The work base can be attached to a steel base attached to the work lifting base with a tightening screw by an adhesive means, and the face plate can be attached to the steel base using a magnet or the like. The material of the reinforcing member does not have to be the same as that of the workpiece as long as it can bond to the workpiece and has the required rigidity, and the size of the reinforcing member must be sufficient to prevent the extra length of the workpiece from bending outward. If satisfied, the size does not need to cover the entire end surface of the work.

As a means for attaching the face plate, for example, a face plate may be attached to the tip of the rod, the rod may be attached to the bearing base so as to be slidable back and forth, and fixed by a tightening screw or the like. The bearing stand can be provided on the magnet base that attracts the steel base. Using a magnet base makes it easy to attach and detach it from a steel base.

When a reinforcing member is provided on the end face of the work and the work is cut, when an outward force is applied to the extra length portion 6-2 during cutting, the reinforcement member can withstand the force. , The extra length does not break. Further, when the face plate is brought into contact with the work end face to cut the work, when an outward force is applied to the extra length portion 6-2 during cutting, the end face of the extra length portion is supported by the face plate. Therefore, the extra length portion does not break.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an example of a method of arranging a reinforcing member on the end face of a work to prevent breakage of a work surplus portion during cutting. FIG. 1A is a front view, FIG. FIG. 6C is a front view showing a part of a state in which the wire is cut in the middle of the dummy plate, and 13 is a reinforcing member.

That is, FIG. 1 exemplifies a method of cutting the dummy plate 8 by providing a reinforcing member 14 on the dummy plate 8, and the reinforcing member 13 is erected on the end of the dummy plate 8 and is bonded with an adhesive. 6 is attached to the end face 6 '. This reinforcing member 1
The height h of 3 does not have to be the same as the height of the work 6,
In FIG. 1C, the work surplus portion 6-2 can be lowered in a range where it does not break at a position above the upper end surface 13-1 of the reinforcing member 13. Further, the width w and the thickness t of the reinforcing member 13 may be determined in consideration of the rigidity so that the work surplus portion 6-2 is not bent. Of course, it is not limited to a single piece, and several reinforcing members may be used to give necessary rigidity as a whole. The material of the reinforcing member is not particularly limited, but is generally made of aluminum.

Further, the bottom portion 13-2 of the reinforcing member 13 has a larger reinforcing effect when it is adhered to the dummy plate 8. However, if the thickness t of the reinforcing member is large, the bottom portion functions to prevent outward collapse. It is preferable that the bonding between the bottom of the reinforcing member and the dummy plate 8 is omitted, or the area where the adhesive is applied is minimized. This is the product wafer 6-
This is because it is possible to reduce the labor for removing the extra length portion 6-2 to which the reinforcing member 13 is bonded from the dummy plate 8 when collecting 1. On the other hand, when the thickness t of the reinforcing member 13 is small, the reinforcing member bottom portion 13-2 and the dummy plate 8 can be adhered to each other easily because they can be easily separated from the dummy plate 8. The reinforcing member 13 may be provided not only on the dummy plate 8 but also on the steel base 9, as shown in FIG.

FIG. 3 shows an example of a method for preventing the breakage of the surplus work portion during cutting by bringing a face plate into contact with the end face of the work.
Drawing (A) is a front view, Drawing (B) is a side view, Drawing (C) is a side view showing a part of state in the middle of cutting, 14 is a face plate support device, 14-1 is a face plate, 14-2 Is a support rod, 14-
3 is a bearing, 14-4 is a tightening screw, and 14-5 is a magnet base.

That is, according to this method, the support rod 14-2 integrated with the face plate 14-1 is supported by the bearing 14-3 so as to be slidable back and forth, and the face plate 14-1 is brought into contact with the end face 6'of the work 6. Tighten the support rod 14-2 at the closed position.
It is a structure fixed by 4, and the magnet base 14-5
It is made detachable on the steel base 9 via. The face plate 14-1 does not need to have a size that covers the entire end face of the work, and may be of a size that does not cause cracking in the work surplus portion of the portion which is not in contact with the face plate 14-1 during cutting. When setting the face plate 14-1,
The face plate 14-1 is brought into contact with the work end surface 6 ′ so that the pressing force is not generated on the work 6. This is because, if a pressing force is applied to the work 6, the work surplus portion 6-2 is bent inward during cutting, and the product wafer 6-1 may be damaged. The magnet base 14-5 is used for the purpose of simplifying the removal of the face plate supporting device 14 after completion of cutting and facilitating the collection of the product wafer 6-1. Although the material of the face plate 14-1 is not particularly limited, it is generally made of aluminum like the reinforcing member.

Example 1 According to the method shown in FIG. 1, end face dimensions of 240 mm × 240 mm,
A quartz work with a length of 100 mm, with a plane dimension of 240 mm ×
180 mm, 10 mm thick glass dummy plate is bonded, and further, the work end surface and the dummy plate are bonded with an aluminum reinforcing member having a width w = 20 mm, a height h = 200 mm, and a thickness t = 30 mm, and a diameter of 0.2 mm. 2mm of piano wire
The dummy plate is adhered to a steel base on a work push-up base of a wire saw in which 49 wire rows are formed by winding the groove roller at a pitch, and an abrasive grain made of silicon carbide having an average particle diameter of 30 μm is attached to the work processed portion. While dripping the abrasive liquid mixed with, while moving the wire row at a speed of 400 m / min in one direction at a high speed, the work lifting platform is gradually raised, and the thickness t ₂ =
As a result of cutting with an extra length of 1.85 mm left, 48 product wafers with a thickness t ₁ = 1.7 mm could be cut at the same time without cracking in the extra length.

On the other hand, when cutting the same work without using the reinforcing member, the thickness t ₂ of the extra length portion is at least 7 to 8 m in order to prevent cracking of the extra length portion during cutting.
The number of product wafers to be cut is 42.

Example 2 According to the method of FIG. 1, the end face has a diameter of 200 mm and a length of 2
00 mm, the flat surface of the silicon work having a flat surface with a width of 60 mm on the outer surface of the cylinder was measured with a plane dimension 7
It is bonded to a ceramic dummy plate having a thickness of 0 mm × 260 mm and a thickness of 15 mm, and a width w = on the end face of the work and the dummy plate.
An aluminum reinforcing member having a thickness of 10 mm, a thickness of t = 30 mm, and a height of h = 150 mm is adhered, and a piano wire having a diameter of 0.2 mm is wound around a groove roller at a pitch of 1.15 mm to make 173.
The dummy plate is adhered to a steel base on a work push-up base of a wire saw on which a plurality of wire rows is formed, and the same row of the polishing liquid as in Example 1 is dropped onto the work processing section, and the wire row is moved to 500 m.
/ While one direction at a high speed travel at a rate gradually increased the work pushing stand, as a result of cutting, leaving the elongated portion of the thickness t2 = 0.95 mm on both ends, the thickness t ₁ = 0.85 mm
It was possible to cut 172 product wafers at the same time.

On the other hand, when cutting the same work without using the reinforcing member, the thickness t ₂ of the extra length portion is at least 3 to 4 mm in order to prevent cracking of the extra length portion during cutting.
The number of product wafers to be cut was 168.

Example 3 According to the method of FIG. 3, end face dimensions of 200 mm × 200 mm,
A ceramic work piece with a length of 100 mm has a plane dimension of 200.
mm × 100 mm, 10 mm thick glass dummy plate, and 0.2 mm diameter piano wire 1.8
The dummy plate is adhered to the steel base on the work lifting table of the wire saw that is wound around the groove roller at a pitch of 55 mm to form a row of 55 wires, and a supporting device having a face plate with a diameter of 100 mm is fixed to the steel base. Then, with the face plate in contact with the end face of the work, the same polishing liquid as in Example 1 is dropped onto the work processing part, and the wire row is run at a speed of 600 m / min in one direction at a high speed to push up the work. As a result of gradually raising the table and cutting with leaving an extra length portion with a thickness t ₂ = 1.25 mm at both ends, 54 product wafers with a thickness t ₁ = 1.5 mm could be cut at the same time. ..

On the other hand, when cutting without using the face plate, the thickness t ₂ of the extra length portion must be at least 3 to 4 mm in order to prevent cracking of the extra length portion during cutting. There was a limit of 52 product wafers to be cut.

[0021]

As described above, according to the method of the present invention, when cutting a brittle material with a multi-wire saw,
Even if the extra lengths at both ends of the work are set to be thin, it is possible to prevent cracks or breaks in the extra length during cutting, so the number of product wafers that can be taken from one work is increased, and The cutting cost can be reduced. Further, if the number of product wafers is constant, the length of the material work can be reduced, so that the material cost can be reduced. The present invention is not limited to the multi-wire saw, and can be applied to a method of simultaneously cutting a large number of blades such as a multi-blade saw.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment corresponding to claim 1 of the present invention, (A) is a front view, (B) is a side view, and (C) is a side view showing a part of a state in which cutting is completed. is there.

FIG. 2 is a view showing another embodiment corresponding to claim 1 of the present invention, (A) is a front view and (B) is a side view.

FIG. 3 is a view showing an embodiment corresponding to claim 2 of the present invention, (A) is a front view, (B) is a side view, and (C) is a side view showing a part of a state during cutting. is there.

FIG. 4 is a perspective view exemplifying a cutting processing portion of a general multi-wire saw.

5A and 5B are diagrams showing a state of completion of cutting with the same multi-wire saw, in which FIG. 5A is a perspective view and FIG. 5B is a partially enlarged side view.

FIG. 6 is an explanatory diagram of forces acting on a work surplus portion and a product wafer during cutting in the same multi-wire saw.

[Explanation of symbols]

 1, 2 and 3 groove roller 4 wire 5 wire row 6 work 6-1 product wafer 6-2 work surplus portion 8 dummy plate 9 steel base 13 reinforcing member 14 face plate support device 14-1 face plate

Claims (2)

[Claims] 1. A cutting fluid is supplied between a traveling wire and an object to be cut, and the object to be cut is ground into a number of wafers by a grinding action while pressing the object to be cut against a wire row of a predetermined pitch formed by the wire. In the multi-wire saw
A cutting method using a multi-wire saw, which comprises arranging a reinforcing member on an end surface of an object to be cut. 2. A cutting fluid is supplied between a running wire and an object to be cut, and the object to be cut is pressed against a wire row of a predetermined pitch formed by the wire to cut into a large number of wafers by a grinding action. In the multi-wire saw
A method for cutting with a multi-wire saw, characterized in that a face plate provided so as to be separable at a position facing the end surface of the object to be cut is brought into contact with the end surface of the object to be cut.