JPH09262829A - Wire saw device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower generation of cracking of a wafer in cutting by a wire saw, by providing a means which prevents an excess slurry spilled from a slurry supply part between a slurry supply part for cutting and a work from sprinkling on the work. SOLUTION: Baffleplates 80A and 80B are mounted on the side of a slurry supply parts 50A and 50B and baffleplates 82A and 82A with respect to a wire 12 are respectively mounted on the opposite side of the slurry supply parts 50A and 50B. Thus, an excess slurry spilled from slurry supply nozzles 50A or 50B to the wire 12 is effectively prevented from scattering and sprinkling on the work by the baffleplates 80A and 80B. That is, the scattering slurry is prevented from sprinkling on an approximately wafer shaped work cut and the work cut does not crack.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire saw for cutting a cylindrical or rectangular work of brittle material such as a semiconductor ingot to form a wafer.

[0002]

2. Description of the Related Art A wire saw is a wire wound in a spiral shape between a plurality of rollers and arranged in parallel with each other in a row at a constant pitch. The wire saw is a cylindrical work such as a semiconductor ingot or a synthetic quartz ingot. While pressing the rectangular work, and supplying a working fluid containing abrasive grains between the work and the wire (hereinafter referred to as cutting slurry or simply slurry), the wire is moved in the line direction to form the work into a wafer. A large number (for example, several hundreds) of wafers having a certain thickness can be cut at the same time.

[0003]

However, in the cutting of the work by the wire saw, the slurry is supplied from the slurry supply unit, for example, the nozzle, and the slurry is supplied to the cutting work unit of the work in a state of viscous adhesion to the wire. However, in order to increase the cutting speed, it is preferable to supply a large amount of slurry.However, when cutting is performed with a large amount of slurry supplied, the cracking of the wafer occurs especially immediately before the cutting of the work is completed. There is a problem that it becomes easier.

The present invention has been made in view of the above points, and an object of the present invention is to provide a wire saw device which reduces the occurrence of cracks in the wafer when the wafer is cut by the wire saw.

[0005]

In order to achieve the above object, the invention described in claim 1 of the present invention is, in a wire saw device, supplied from a slurry supply section between a cutting slurry supply section and a work. It is characterized in that means for preventing excessive slurry from being sprinkled on the work is provided.
As described above, by providing the means for preventing the excessive slurry from splashing on the work, it is possible to prevent the work portion already cut during the cutting from vibrating and causing the wafer to crack.

A baffle plate is effective as a means for preventing the excess slurry from being sprinkled on the work (claim 2), and prevents the excess slurry from being sprinkled on the work. Means for the wire on the same side as the slurry supply part (claim 3) or on the wire for the opposite side to the slurry supply part (claim 4),
It is desirable that it is provided on both sides of the wire (claim 5).

Further, the means for preventing the excessive slurry from being sprinkled on the work is preferably provided so as to come into contact with the wire, in order to completely prevent the slurry from being sprinkled on the work ( (Claim 6), and preferably, it is provided so that its position and installation height can be changed (Claim 7). When the height of the means for preventing the excess slurry from splashing on the work is at least twice the outer diameter of the work, the slurry is prevented from splashing over the entire range of movement of the work during cutting. It is possible (claim 8).

Hereinafter, the present invention will be described in more detail. The present inventors investigated and examined the cause of wafer cracking during work cutting with a wire saw device, and as a result, in cutting the work with a wire saw, slurry was supplied from a slurry supply nozzle, and the slurry was viscously attached to the wire. Although it is supplied to the cutting processing part of the work in a state, it is preferable to supply a large amount of slurry in order to increase the cutting speed, but when cutting is performed under these conditions, part of the supplied slurry is part of the work. It was found that the phenomenon of scattering from the wire occurs before reaching the cutting processing part of. Most of the scattered slurry hits the work and the supporting member that supports the work, but when the scattered slurry is sprinkled on the part where the cutting of the work has already ended, vibration occurs at the part where the cutting ends, especially, Immediately before the cutting of the work was completed, it was discovered that the vibration of the part where the cutting was completed increased, resulting in the cracking of the wafer, and the excess slurry was sprinkled on the work using the baffle plate. The present invention has been completed by confirming that prevention is effective in reducing the occurrence of cracks.

[0009]

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto. Here, FIG. 1 is a schematic view of a wire saw, and FIG. 2 is a schematic view showing a cross section of the wire saw in the embodiment of the present invention. In addition, FIG. 3 is a schematic view showing how the polishing slurry is scattered when the work is cut by a conventional wire saw. FIG. 4 is a schematic view showing how the polishing slurry is scattered when the work is cut by the wire saw of the present invention.

First, FIG. 1 is a schematic view showing a schematic structure of a wire saw. In this wire saw, the wire 12 wound around two wire winding drums 22 and 32 driven by torque motors 24 and 34, respectively, is spirally wound between three rollers 10A, 10B and 10C. And the wires 12 are parallel to each other at a constant pitch between the two rollers 10A and 10B,
The work is cut at this part. Further, the wire 12 can be moved at a predetermined speed by rotationally driving the roller 10C by the drive motor 7 connected to the lower roller 10C, for example. Then, when the wire 12 is wound from the wire winding drum 22 to the other wire winding drum 32 or in the opposite direction at a predetermined linear velocity via the tension adjusting mechanisms 20 and 30, a cutting slurry (not shown) While the slurry is supplied from the supply device to the work cutting portion via the wire 12, the work 40 held by the work holder 42 is pressed against the work cutting portion between the two rollers 10A and 10B, whereby the work 40 Is disconnected.

FIG. 2 is a schematic sectional view showing an embodiment of the present invention when the wire saw of FIG. 1 is viewed from the direction A.
The cutting slurry 62 stored in the slurry tank 60 is pressurized by the pump 66, supplied to the wire 12 from the slurry supply nozzle 50A or 50B through the slurry supply pipe 64, and is used for cutting the work 40. The slurry scattered from the cutting portion of the work 40 and the wire 12 is collected at the bottom of the wire saw cover 70 and collected in the slurry tank 60 by the slurry collecting pipe 72.
A circulation system is formed again through the slurry supply pipe 64 to be supplied to the cutting portion of the work 40.

The cutting slurry is composed of two rollers 10A.
And the slurry supply nozzle 50 directly above the center line of 10B
A is supplied from A and 50B, but when the wire 12 is sent from the roller 10A to the roller 10B when cutting the work, the slurry is supplied from the slurry supply nozzle 50A, and when it is sent in the opposite direction, the slurry is supplied. It is supplied from the supply nozzle 50B. The slurry supply nozzles 50A and 50B have a large number of nozzles arranged in the longitudinal direction of the roller 10A or 10B.
The slurry flow is curtain-shaped.

Roller 10A or 10B and work 4
Between 0 and 0, the slurry supply unit 50 for the wire
Baffle plates 80A and 80B are provided on the same side as A and 50B, and baffle plates 82A and 82B are provided on the opposite side to the slurry supply unit, respectively, and slurry supply nozzle 50A or 50B is provided.
The excess slurry supplied from the wire 12 to the wire 12 scatters on the work and is effectively prevented from being sprinkled by the baffle plate.

FIG. 3 is a schematic view showing how the slurry is scattered when cutting a work with a conventional wire saw. A part of the slurry supplied to the wire 12 from the slurry supply nozzle 50A or 50B immediately above the roller 10A or 10B adheres to the wire 12 to reach the work cutting portion, but excess slurry is scattered slurry 5
2 and sprinkles on the work 40 or the work holder 42. When the cutting of the work 40 progresses and approaches the end of cutting, if the scattered slurry 52 is sprinkled on the cut wafer-shaped cut work, the vibration of the cut work becomes large, which causes cracking. On the other hand, by providing the baffle plate according to the present invention, the baffle plates 80A, 80B, 82A and 82B completely prevent the scattered slurry 52 from being sprinkled on the work 40 as shown in FIG.

The baffles are preferably provided on both sides of the wire as shown in FIG. 4, but as shown in 80A and 80B, only on the same side of the wire as the slurry supply section, or 8
It is also possible to provide it only on the side opposite to the slurry supply part with respect to the wire like 2A and 82B. In this case, while the work 40 is being cut, the scattered slurry 52 is completely dispersed in the work 4.
In order to prevent the baffle from swinging to 0, it is preferable to install the baffle plate at least over a range in which the work 40 moves, that is, at least twice the outer diameter thereof.

The baffles 80A, 80B, 82A, 8
2B is preferably provided so as to contact the wire 12. This is to completely prevent the scattered slurry 52 from being splashed on the work 40. Further, it is preferable that the baffle plate is detachably provided so that the position and height of the baffle plate can be changed in consideration of the adjustment of the slurry scattering prevention state and the convenience of setting the wire. The position of the baffle plate may be manually changed, or may be automatically changed using a motor so as to move in association with the work as the cutting of the work 40 progresses. It is also possible to form a groove in the portion of the baffle plate that comes into contact with the wire in accordance with the pitch of the wire, and this groove can be formed by partially cutting the baffle plate with a wire saw. it can.

The material of the baffle is preferably a hard resin, and relatively inexpensive polyvinyl chloride, polyethylene,
Polypropylene or the like can be used. Polyimide sinter, polyether ether ketone (P
Engineering plastics such as EEK), polyacetal, polyethylene terephthalate (PET), polyamide, and polyamide-imide can be used. Further, the baffle plate is preferably transparent so that the cutting state can be visually confirmed.

[0018]

EXAMPLES Examples of the present invention and comparative examples will be described below. (Example) Using a wire saw of the present invention in which baffles made of vinyl chloride are provided on both sides of the wire, the diameter is about 200 mm.
The semiconductor silicon single crystal ingot was cut. Wire speed of 500m / min, slurry flow rate of 120
Approximately 250 cutting of 10 ingots at 1 / min
0 wafers were cut out. The crack occurrence rate at this time was 0.5%.

(Comparative Example) The baffle plate was removed from the wire saw used in the example, and the diameter was about 20 in the same manner as in the example.
A 0 mm semiconductor silicon single crystal ingot was cut. Five ingots were cut to cut out about 1000 wafers. The crack occurrence rate at this time was 3.5%.

In the comparative example, the crack generation rate was 3.5%, while in the example, it was greatly reduced to 0.5%, and the cutting yield and productivity were improved.

The present invention is not limited to the above embodiment. The above embodiment is an exemplification, and has substantially the same configuration as the technical idea described in the scope of the claims of the present invention. It is included in the technical scope of the invention.

For example, in the above embodiment, the case where the baffle plate is used as the means for preventing the excessive slurry from splashing on the work has been described as an example, but the present invention is not limited to this. Any shape may be used as long as it can prevent the excessive slurry from splashing on the work.

[0023]

As described above, the wire saw of the present invention is provided with a means for preventing an excessive slurry from being sprinkled on the work between the cutting slurry supply section and the work, thereby making Wafer crack occurrence rate is reduced and cutting yield and productivity can be improved. Therefore, the utility value of the present invention in industry is extremely high.

[Brief description of drawings]

FIG. 1 is a schematic view of a wire saw.

FIG. 2 is a schematic view showing a cross section of the wire saw of the present invention.

FIG. 3 is a schematic view showing how the polishing slurry is scattered when a work is cut by a conventional wire saw.

FIG. 4 is a schematic view showing how the polishing slurry is scattered when cutting a work with the wire saw of the present invention.

[Explanation of symbols]

 7 ... Drive motor, 10A, 10B, 10C ... Roller, 12 ... Wire 20, 30 ... Tension adjusting mechanism, 22, 32 ... Wire winding drum, 24, 34 ... Torque motor, 40 ... Cylindrical work, 42 ... Work holder , 50A, 50B ... Slurry supply nozzle, 52 ... Scattered slurry, 60 ... Slurry tank, 62 ... Slurry, 64 ... Slurry supply pipe, 66 ... Slurry pump, 70 ... Wire saw cover, 72 ... Slurry recovery pipe, 80A, 80B, 82A, 82B ... Baffle plates.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kohei Sotoyama Odaira, Saigomura, Nishishirakawa-gun, Fukushima Odaira 150 Shin-Etsu Semiconductor Co., Ltd. Shirakawa factory

Claims (8)

[Claims] 1. The wire saw device is provided with a means for preventing the excess slurry supplied from the slurry supply section from being sprinkled on the work between the cutting slurry supply section and the work. Wire saw device. 2. The wire saw device according to claim 1, wherein the means for preventing the excessive slurry from splashing on the work is a baffle plate. 3. The means for preventing the excess slurry from being sprinkled on the work is provided on the same side of the wire as the slurry supply section.
Alternatively, the wire saw device according to claim 2. 4. The means for preventing the excessive slurry from being sprinkled on the work, the means being provided on the side opposite to the slurry supply section with respect to the wire. The wire saw device according to any one of claims. 5. The device according to claim 1, wherein means for preventing the excess slurry from splashing on the work is provided on both sides of the wire. The described wire saw device. 6. The method according to claim 1, wherein a means for preventing the excess slurry from splashing on the work is provided so as to come into contact with the wire.
The wire saw device according to any one of 1. 7. The means for preventing the excessive slurry from splashing on the work is provided so that its position and installation height can be changed.
The wire saw device according to claim 6. 8. The height of the means for preventing the excessive slurry from splashing on the work is at least twice the outer diameter of the work or more, according to any one of claims 1 to 7. The wire saw device according to one item.