JPH10151559A - Wire for wire saw and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire for a wire saw capable of carrying out smooth slicing only by pouring water on a slicing part and free to use several times without using it up for one time by fundamentally changing a conventional slicing method and holding abrasive grains on a surface and inside of the wire itself and to provide its manufacturing method. SOLUTION: Held polytetrafluoroethylene (B) is sintered and a tetrafluoroethylene-perfluoroalkylvinylether copolymer (C) is molten by dispersing polytetrafluoroethylene (B) as an essential component, dispersing the tetrafluoroalkylvinylether copolymer (C) as an optional component and holding abrasive grains (D) as an essential component on a heat-resisting high strength fiber multiflament thread (A) and thereafter, applying shearing force and heat treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire for a wire saw for slicing a hard and brittle material such as a single crystal ingot and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, slicing of a single crystal ingot such as a silicon ingot has been performed using an outer peripheral edge or an inner peripheral edge of a disk or a ring-shaped disk, but the diameter of the ingot is, for example, 8 inches or more. When it becomes larger, smooth slicing becomes difficult. Therefore, a wire saw has been used for slicing a large-diameter ingot.

As a wire for a wire saw, a metal wire (especially a piano wire) is exclusively used, and slicing is performed while a working liquid composed of oil in which abrasive grains such as diamond are dispersed is adhered to the wire.

[0004] Since the use of oil as a dispersion medium has various disadvantages in terms of post-treatment, the use of an aqueous dispersion medium as a dispersion medium has been studied.

For example, JP-A-3-181598 discloses a thickening agent comprising a base oil (1) selected from polyethylene glycol, polypropylene glycol or polyoxyethylene-oxypropylene, a polyalkylene glycol derivative or a high molecular weight polysaccharide. Agent (2) and water
A medium containing (3) is used. JP-A-4-2168
In Japanese Patent Publication No. 97, a water-soluble processing liquid containing glycols (1), a water-soluble thickener (2) and water (3) as essential components is used. In JP-A-4-218594,
A water-soluble working fluid comprising a glycol (1), a water-soluble thickener (2) and water (3) is used.

A recently disclosed Japanese Patent Application Laid-Open No. 8-126953 discloses that a large number of wires that are wound around a plurality of rotationally driven multi-groove pulleys and move between the pulleys are pressed against a work (workpiece). In a wire saw for cutting or grooving a workpiece with the wire, the wire has a core wire made of polyethylene, nylon, polyester, or the like, or a glass fiber made of these materials.
A wire saw made of a material reinforced with carbon fibers and having abrasive grains fixed to the outer periphery of the core wire and a method of manufacturing a wire for the wire saw are shown.

In the description of the prior art in this publication, the configuration and use of wires and abrasive grains in a conventional wire saw cutting apparatus include (a) bonding abrasive grains such as carborundum to the outer periphery of a piano wire. (B) Free abrasive grains that are cut by lapping while supplying a slurry in which the abrasive grains are mixed with a special oil or aqueous agent while the wire is in contact with the workpiece. There is a description that there are two types of methods.

[0008]

However, in the system using an aqueous dispersion medium as the dispersion medium, the amount of the abrasive particles attached to the metal wire is reduced, so that it is difficult to perform the slicing operation. In particular, when the proportion of water increases, the slicing operation becomes extremely difficult.

[0009] Therefore, the above-mentioned JP-A-3-181598, JP-A-4-216897, and JP-A-4-218.
In Japanese Patent No. 594, a water-soluble thickener is used in combination to prevent the sedimentation of the paint in the water-soluble working fluid or to secure the amount of abrasive particles attached to the wire. In addition to the physical and microbiological contamination of ingots, the use of phenol has a new problem in that wastewater treatment requires an enormous amount of equipment.

The above-mentioned Japanese Patent Application Laid-Open No. Hei 8-1269 recently published
In the invention of JP-A-53-53, the core wire is composed of a material made of polyethylene, nylon, polyester, or the like, or a material reinforced with glass fiber or carbon fiber. Abrasive particles are fixed. "
Although the cutting process is performed while injecting a coolant made of simple water into the cutting portion by using the above, the abrasive grains are fixed using a synthetic resin adhesive, so that the trouble of wastewater treatment is reduced. In addition to the problem, since the abrasive grains are fixed to the outer periphery of the core wire, there is a limit that the abrasive grains are consumed by one operation and can be used only once. Also, since the core wire is made of general-purpose synthetic fiber, the wire may be cut unexpectedly during the cutting operation, or the wire may be partially cut even if it is not cut, and the cut surface will not be beautiful There is.

Under such a background, the present invention fundamentally revises the conventional slicing method so that abrasive grains are carried on the surface and inside of the wire itself, and smooth slicing is achieved simply by pouring water into the slicing portion. Can do
Moreover, it is an object of the present invention to provide a wire for a wire saw that can be used several times without using up at one time, and a method for manufacturing the same.

[0012]

The wire for a wire saw according to the present invention is a heat-resistant high-strength fiber multifilament yarn (A).
In addition, polytetrafluoroethylene (B) as an essential component
, A tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (C) as an optional component, and abrasive grains (D) as an essential component are supported, and the supported polytetrafluoroethylene (B) is sintered. It is characterized by having.

The method for producing a wire for a wire saw according to the present invention comprises:
A heat-resistant high-strength fiber multifilament yarn (A) is prepared by dispersing polytetrafluoroethylene (B) as an essential component and tetrafluoroethylene- as an optional component.
After supporting the dispersion of the perfluoroalkyl vinyl ether copolymer (C) and the abrasive grains (D) as an essential component, applying a shearing force, and then performing a heat treatment, the polytetrafluorocarbon ethylene
(B) and melting the tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (C).

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In this specification, “slicing” is a concept that includes not only slicing in a narrow sense but also grooving and simple cutting.

Heat resistant high strength fiber multifilament yarn
(A) includes metal fibers (stainless steel fibers, shape memory alloys, etc.), ceramic fibers, glass fibers, carbon fibers, polyparaphenylene benzobisoxazole fibers, aramid fibers, polyetheretherketone fibers,
Examples include multifilament yarns made of polyamide imide fibers, polyimide fibers, polybenzimidazole fibers, liquid crystal polyester fibers, and the like, and two or more fibers can be used in combination. Among these, liquid crystal spun fibers of polyparaphenylenebenzobisoxazole, which are particularly excellent in heat resistance and high strength, are particularly important. The heat resistance means that it can withstand the sintering temperature of polytetrafluoroethylene (B).

In order to obtain a constant wire diameter, it is desirable that the heat-resistant high-strength multifilament yarn (A) is twisted. When a strong twist has already been applied, the twist is slightly loosened if necessary. The thickness of the heat-resistant high-strength multifilament yarn (A) is desirably as thin as possible as long as it has a predetermined strength. Since the current wire diameter is about 0.2mm,
Even in the present invention, the diameter at the stage of forming a wire is set to this level even if it is large, but it is easy to set it to about 0.15 mm.For example, if the above-mentioned polybenzobisoxazole fiber is used, for example, 0.05 mm The wire diameter can be made much smaller, such as to the extent.

The heat-resistant high-strength multifilament yarn (A) includes a dispersion of polytetrafluoroethylene (B), a dispersion of tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (C), and abrasive grains. (D). Among them, the component (C) is an optional component, and it is particularly desirable to use the component (C) together.

The dispersion of the polytetrafluoroethylene (B) and the dispersion of the tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (C) are in a desired amount with respect to the heat-resistant high-strength multifilament yarn (A). An appropriate concentration is set so that the above (B) and (C) can be carried smoothly, and further, the abrasive grains (C) can be carried smoothly. (B)
The dispersion of (C) and the dispersion of (C) are both commercially available from various companies, so that the concentration may be adjusted if necessary.

As the abrasive grains (D), diamond is suitably used, and carborundum, alumina and the like can also be used. In addition, various other abrasive grains conventionally used for wire saws can also be used.

Heat resistant high strength fiber multifilament yarn
When the total amount of (B) and (C) is 100% by weight, the ratio of (B) is 2 to 100%.
% By weight (preferably 5 to 99% by weight, especially 10 to 95% by weight, more preferably 30 to 70% by weight), and the proportion of (C) is 98%.
To 0% by weight (preferably 95 to 1% by weight, especially 90 to 5% by weight).
% By weight, even 70 to 30% by weight), and (D)
Is 10 to the total amount of (B), (C) and (D).
It is preferably 80% by weight (particularly 30 to 70% by weight). In such a range, the intended purpose is achieved.

Heat resistant high strength fiber multifilament yarn
After supporting the above components (B), (C) and (D) on (A), a shearing force is applied, followed by a heat treatment.
The supported polytetrafluoroethylene (B) is sintered and the tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (C) is melted. Passing the wire through alcohol before or after the application of the shearing force makes the anchorage of the dispersion more favorable. By the above operation, the target wire saw wire is manufactured.

In order to apply a shearing force, for example, a method is adopted in which the heat-resistant high-strength multifilament yarn (A) after being supported is passed through a narrow overflow portion so as to be squeezed.

The temperature of the heat treatment is suitably about 350 to 400 ° C., and may be higher than that in a short time.

The wire for a wire saw thus obtained can be suitably used as a wire for slicing a single crystal ingot such as a silicon ingot, a gallium-arsenic ingot, and a gallium-phosphorous ingot. Further, the present invention can be used not only for a single crystal ingot but also as a wire for a wire saw for slicing a polycrystalline ingot and various hard and brittle materials (semiconductor material, magnetic material, ceramics, glass, etc.).

<Action> Polytetrafluoroethylene (B)
When the shearing force is applied to the dispersion, the dispersion becomes extremely fine, so that the abrasive grains (D) are not scattered by being entangled with the fiberized polytetrafluoroethylene (B). However, since polytetrafluoroethylene (B) has poor adhesion to the heat-resistant high-strength multifilament yarn (A), it may not be sufficient alone. In such a case, if the tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (C) is used in combination, the tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (C) becomes a heat-resistant high-strength fiber multifilament yarn ( The adhesive strength to both (A) and polytetrafluoroethylene (B) is excellent, so that polytetrafluoroethylene (B) and abrasive grains (D) entangled with it are also heat-resistant high-strength multifilament yarns (A ) Will be carried with the necessary adhesive force. And polytetrafluoroethylene
(B) is finally sintered and becomes strong and exhibits slipperiness.When the obtained wire is used as a wire for a wire saw and subjected to a slicing operation, the wire smoothly contacts the ingot and is carried. Slicing is achieved by the abrasive grains (D). In addition, not only the polytetrafluoroethylene (B) is sintered, but the tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (C) melts, so that the twist of the heat-resistant high-strength multifilament yarn (A) returns. The wire diameter does not change. In the slicing operation, smooth slicing can be performed simply by pouring water into the slicing portion, and it is possible to use the wire several times without using up the wire once.

As described above, in the present invention, since the abrasive grains (D) are carried on the surface and inside of the wire itself, smooth slicing can be performed simply by using water, and the abrasive grains for the wire can be incorporated. It is released from the control of the supply of the working fluid, and can be used several times repeatedly. In the wastewater treatment, the abrasive can be discharged simply by collecting the abrasive as needed. Therefore, the present invention is extremely advantageous industrially.

[0027]

The present invention will be further described with reference to the following examples.

Embodiment 1 FIG. 1 is a process diagram schematically showing an example of a method for manufacturing a wire for a wire saw according to the present invention.

Heat resistant high strength fiber multifilament yarn
(A) as 0.15mm thick stainless steel thread, thickness
Polyparaphenylene benzobisoxazole fiber multifilament yarn with 0.10mm and 0.06mm thickness, 0.15mm thickness
Of aramid fiber multifilament yarn and polyetheretherketone fiber multifilament yarn having a thickness of 0.15 mm.

As a dispersion of polytetrafluoroethylene (B), a dispersion having a resin concentration of 60% by weight was prepared. A dispersion having a resin content of 50% by weight was prepared as a dispersion of the tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (C).

Further, as abrasive grains (D), diamond fine particles conventionally used as abrasive grains for wire saws were prepared.

The dispersion of polytetrafluoroethylene (B), the dispersion of tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (C), and the abrasive (D) are referred to as (B) and (C). ) Is 100% by weight, the proportion of (B) is 50% by weight,
The proportion of (C) is 50% by weight, and the proportion of (D) is
A treatment liquid was prepared by mixing the components (B), (C) and (D) at a ratio of 50% by weight with respect to the total amount. That is, the weight ratio of (B), (C), and (D) in the processing solution is 25:
25:50.

This treatment liquid is placed in a tank and placed under gentle stirring, and the bath is heat-resistant and high-strength multifilament yarn.
(A), the yarn (A) is impregnated with the treatment liquid, then, if necessary, once passed through alcohol, and then subjected to a shearing force through a squeezing roll, and further introduced into a dryer to be dried. , Wound up. Then, the wound wire is heated in a firing furnace at a temperature of 370 ° C. to sinter the supported polytetrafluoroethylene (B) and to convert the tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (C). Melted.

As a result, a desired wire saw wire was obtained. When slicing a silicon ingot using this wire by a conventional method, smooth slicing could be achieved simply by pouring water into the slicing portion. Several repetitions were possible.

[0035]

According to the wire saw wire of the present invention, since the surface and the inside of the abrasive grains (D) are carried on the wire itself, smooth slicing can be performed simply by pouring water into the slicing portion. This makes it possible to release the control of the supply of the abrasive-containing working fluid to the wire, to allow repeated use several times, and to discharge the wastewater only by collecting the abrasive if necessary. Therefore,
The present invention is extremely advantageous industrially.

[Brief description of the drawings]

FIG. 1 is a process diagram schematically showing an example of a method for manufacturing a wire for a wire saw according to the present invention.

[Explanation of symbols]

(A) ... heat-resistant high-strength fiber multifilament yarn, (B) ... polytetrafluoroethylene, (C) ... tetrafluoroethylene-perfluoroalkylvinyl ether copolymer, (D) ... abrasive

Claims (5)

[Claims] 1. A heat-resistant high-strength multifilament yarn.
(A) has polytetrafluoroethylene as an essential component
(B), a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (C) as an optional component, and abrasive grains (D) as an essential component are supported, and the supported polytetrafluoroethylene (B) is A wire for a wire saw, which is sintered. 2. When the total amount of (B) and (C) is 100% by weight, the proportion of (B) is 2 to 100% by weight, the proportion of (C) is 98 to 0% by weight, and The proportion of (D) is (B),
The wire for a wire saw according to claim 1, wherein the amount is 10 to 80% by weight based on the total amount of (C) and (D). 3. When the total amount of (B) and (C) is 100% by weight, the proportion of (B) is 5 to 95% by weight and the proportion of (C) is 95 to 5% by weight. 3. The wire for a wire saw according to 2. 4. The wire for a wire saw according to claim 1, which is a wire for slicing a single crystal ingot. 5. A heat-resistant high-strength fiber multifilament yarn.
(A) has polytetrafluoroethylene as an essential component
After supporting the dispersion of (B), the dispersion of the tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (C) as an optional component, and the abrasive grains (D) as an essential component, a shearing force is applied, Then, by performing a heat treatment, the supported polytetrafluoroethylene (B) is sintered and the tetrafluoroethylene-perfluoroalkylvinyl ether copolymer (C) is melted to produce a wire for a wire saw. Law.