JP3804723B2 - Modification method of main roller and guide roller of wire saw device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for modifying a main roller and a guide roller used in a wire saw device used in a process of slicing a semiconductor silicon single crystal ingot (hereinafter, sometimes simply referred to as an ingot), and a modified main roller and guide. Concerning Laura.
[0002]
[Related technologies]
Conventionally, a wire saw device as shown in FIG. 1 has been used as a workpiece cutting device for cutting or slicing a workpiece, for example, a semiconductor silicon single crystal ingot, into a wafer.
[0003]
In FIG. 1, the wire saw device 12 is configured by arranging three main rollers 14, 16, and 18 in parallel with each other at respective vertex positions of the triangle and rotatably, and between these main rollers 14, 16, and 18. One wire 20 made of a special piano wire having a wire diameter of about 0.08 to 0.25 mm is spirally wound at a predetermined pitch to form a wire row. A plurality of the main rollers may be disposed, and the number of the main rollers is not particularly limited, but three or four illustrated are usually used.
[0004]
Each main roller 14, 16, 18 is provided with a groove for winding the wire 20. FIG. 2 shows the groove 14 a of the main roller 14. FIG. 4A shows the shape of the groove 14a when the main roller 14 is new. In this case, the groove pitch e of the new groove 14a is constant as shown. On the other hand, FIG. 4B shows the groove 14a when the main roller 14 has reached the end of its life. In this case, the groove pitch of the groove 14a that has reached the end of life is not constant as shown.
[0005]
A work W such as a cylindrical semiconductor silicon ingot held by a work holder 22 is located between the upper two main rollers 14 and 16, that is, in a cutting region and above the main rollers 14 and 16. It is set. The work W moves up and down together with the work holder 22 when the work holder 22 is moved up and down by driving means (not shown).
[0006]
The lower main roller 18 is a drive main roller, and this is rotated forward and backward by a drive motor 24.
[0007]
Above the main rollers 14, 16, a nozzle 28 is installed to eject abrasive slurry 26 made by suspending fine abrasive grains with an oily or water-soluble coolant. A slurry reservoir 30 is provided between the main rollers 14 and 16 and receives the slurry 26 ejected from the nozzle 28. The slurry 26 is stored in a slurry tank (not shown).
[0008]
The wire 20 spirally wound between the plurality of main rollers 14, 16, 18 is moved while reciprocating from the wire sending side to the wire receiving side. A guide roller 32 guides the wire wound around the main rollers 14, 16, and 18 on the wire sending side and the receiving side.
[0009]
A plurality of wafers can be cut out simultaneously by pressing the workpiece W to the wire 20 moving in this manner at a predetermined feed rate and supplying the slurry 26 to the pressing portion. And since this wire saw apparatus 12 can cut | disconnect many wafers simultaneously, it replaces with the conventional inner peripheral blade slicer etc., and is used abundantly.
[0010]
Currently, in the slicing processing of a semiconductor silicon single crystal ingot, a wire saw device is generally introduced as an ingot slicing device as the diameter becomes larger, such as φ200 mm and φ300 mm.
[0011]
In this wire saw apparatus, studies are made on abrasive grains, coolant, wires, main rollers, guide rollers, and the like for the purpose of improving productivity and stable operation.
[0012]
For example, for the wire, the wire storage dose is increased and the replacement frequency is decreased, or in the main roller and guide roller, a metal roller coated with polytetrafluoroethylene from a high-density polyethylene, It has been attempted to shorten the replacement time required for replacement of the main roller by changing to hard urethane resin and improving the life of the main roller and guide roller.
[0013]
Even if the ingot is cut using such a hard urethane resin main roller and guide roller, the waviness (cross-sectional shape) value of the cut wafer or the warp value that is the essential quality of the cut wafer is shown in FIG. a) As shown in (b), the groove shape of the main roller tends to fluctuate with time, which tends to deteriorate with the life of the hard urethane resin. On the other hand, even if it is a new main roller and a guide roller, there may exist a thing which shows a bad tendency from the use initial stage.
[0014]
Because of this tendency, for the first time, it is necessary to replace the main roller made of hard urethane resin from the viewpoint of the management of the warped value of the cut wafer. Increased burden on replacement work is a problem.
[0015]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problems of the prior art, and by stabilizing the quality of the hard urethane resin that is the material of the main roller, the life of the main roller and the guide roller made of hard urethane is extended. An object of the present invention is to provide a method for modifying a main roller and a guide roller and a modified main roller and guide roller in a wire saw device that can be made constant and free from variations.
[0016]
[Means for Solving the Problems]
In order to solve the above-described problems, a method for modifying a main roller and a guide roller of a wire saw device according to the present invention is a wire saw device having a main roller and a guide roller, and the main roller and the guide roller are made of a hard urethane resin. Then, after grinding the respective main rollers and guide rollers made of hard urethane resin to give a predetermined dimensional accuracy, the final finish is applied to the surfaces of the main rollers and guide rollers made of hard urethane resin. and facilities cold oxygen plasma treatment, and the low-temperature oxygen plasma treatment are due to glow discharge vacuum oxygen gas, the pressure range of the oxygen gas in the plasma generating unit is an 0.01~0.5torr The treatment temperature is 10 to 40 ° C., and the treatment time is 1 to 2 minutes .
[0017]
The hard urethane resin main roller and guide roller are each subjected to final grinding and grooving and dimensional accuracy, and then subjected to low-temperature oxygen plasma treatment as a final finish. It is applied to the surface of the guide roller.
[0018]
The low-temperature oxygen plasma treatment is based on glow discharge in reduced-pressure oxygen gas, the pressure range of the oxygen gas in the plasma generation part is 0.01 to 0.5 torr, the treatment temperature is 10 to 40 ° C., Processing time is performed on the conditions for 1-2 minutes.
[0019]
As described above, the main roller and the guide roller made of hard urethane resin subjected to the low-temperature oxygen plasma treatment have a uniform surface and less variation, and stably cut the ingot by the wire saw device. It becomes possible.
[0020]
【Example】
Examples of the present invention will be described below.
[0021]
Production Example 1
The main roller and guide roller processed to a predetermined dimensional accuracy by grinding were placed in a chamber and subjected to a low-temperature oxygen plasma treatment. This low-temperature oxygen plasma treatment depends on glow discharge in reduced-pressure oxygen gas, the pressure range of oxygen gas is 0.01 to 0.5 torr, the treatment temperature is 10 to 40 ° C., and the treatment time is 1 ~ 2 minutes.
[0022]
Example 1
As a result of slicing a φ200 mm ingot using the wire saw device shown in FIG. 1 incorporating a main roller subjected to low-temperature oxygen plasma treatment under the conditions of Production Example 1, it was possible to cut 120 ingots.
[0023]
Comparative Example 1
For comparison, when a slicing of φ200 mm ingot was performed using a main roller made of a hard urethane resin that was simply ground and not subjected to low-temperature oxygen plasma treatment, only 60 ingots were cut on average from 10 to 100 ingots It was not obtained.
[0024]
Therefore, it was confirmed that the main roller made of hard urethane resin subjected to the low-temperature oxygen plasma treatment of the present invention has a life approximately twice that of the conventional main roller made of hard urethane resin.
[0025]
Example 2
Further, when slicing a φ200 mm ingot using the wire saw apparatus shown in FIG. 1 in which a guide roller made of hard urethane resin subjected to low-temperature oxygen plasma treatment under the conditions of Production Example 1 was incorporated, one groove was obtained. / 4 ingot could be cut.
[0026]
Comparative Example 2
On the other hand, with a conventional guide roller made of hard urethane resin, the groove state of the guide roller must be confirmed every time one ingot is cut with an average of about 1 groove / 1 ingot.
[0027]
【The invention's effect】
As described above, according to the present invention, the workability is improved by extending the life of the main roller and the guide roller, and in addition, the waviness (cross-sectional shape) value of the cut wafer or the essential of the cut wafer is obtained. The warp value, which is the quality, can be stabilized for a long time, and the life of the main roller and guide roller can be extended, leading to a significant effect of reducing the cost of ingot cutting work by the wire saw device. be able to.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a wire saw device.
FIGS. 2A and 2B are partial cross-sectional views showing the groove shape of the main roller. FIG. 2A shows the groove shape of a new main roller, and FIG. 2B shows the groove shape of the main roller that has reached the end of its life.
[Explanation of symbols]
12: wire saw device, 14, 16, 18: main roller, 20: wire, 14a: groove, 22: work holder, 24: drive motor, 26: abrasive slurry, 28: nozzle, 30: slurry reservoir, 32: Guide roller, W: Workpiece.

Claims (2)

In a wire saw apparatus having a main roller and a guide roller, the main roller and the guide roller are made of a hard urethane resin, and each of the hard urethane resin main roller and the guide roller is ground to have a predetermined dimensional accuracy. after issuing the, and facilities low temperature oxygen plasma treatment to the surface of the rigid urethane resin main roller and the guide roller as a finishing touch, and the low-temperature oxygen plasma treatment is due to glow discharge vacuum oxygen gas The pressure range of the oxygen gas in the plasma generation part is 0.01 to 0.5 torr, the processing temperature is 10 to 40 ° C., and the processing time is 1 to 2 minutes. Reforming method for main roller and guide roller. A main roller and a guide roller made of hard urethane resin in a wire saw device, wherein the main roller and the guide roller are modified by the method according to claim 1.

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