JPH10138114A - Wire for wire saw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the slice efficiency, and to reduce the slice time by providing a high tensile metallic wire as the stock wire, and carrying abrasive grains made of the material other than the metal such as organic or inorganic material on the surface of the stock wire. SOLUTION: The solution in which the binder 3 consisting of the material other than the metal, e.g. organic material such as polyamide-imide and inorganic material such as glass is melded in the solvent, is mixed, and the abrasive grains 4 are dispersed in the solution. The abrasive dispersed solution is applied to the surface of a stock wire 2 comprising a brass-plated piano wire, and the stock wire 2 is passed through a heating furnace to perform the baking and to manufacture a wire 1 for wire saw. Because the wire 1 for wire saw is of the double abrasive grain system including the abrasive grain 4 on the surface and the abrasive grain in the abrasive grain slurry, the biting performance of the abrasive grain is remarkably improved, and the slice efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wire for a wire saw, and more particularly to a wire for a wire saw used for cutting a semiconductor silicon ingot, a compound semiconductor ingot, a magnetic material, a crystalline lens, and the like.

[0002]

2. Description of the Related Art Conventionally, in order to cut a wafer or a chip as a semiconductor or electronic material from a base material, an inner peripheral cutter, a wire saw, and a part of an outer peripheral cutter are used.

[0003] In recent years, the diameter of silicon wafers has been increasing, but the technical limit of wafer slicing with an inner peripheral cutter is up to 8 "(inch) products, and the profitability of production is 6". The view to the product is influential.

[0004] Compared with the wafer slice by the inner / outer peripheral cutter, the wafer slice by the wire saw is
Since a large number of wafers (50 or more in some cases) can be sliced at the same time, and essentially high throughput can be expected, it is currently being used actively.
It is anticipated that a 12 ″ product, for which demand is expected in the future, will naturally be a wafer slice by a wire saw.

In general, a wire saw is run while pressing a piano wire against an ingot, and a special cutting oil (hereinafter, referred to as an abrasive slurry) in which abrasive grains are dispersed in a lubricating oil is injected into a contact portion of the wire saw to thereby form a base material. A free abrasive slurry injection method for slicing is used.

FIG. 4 is a perspective view of a conventional wire saw device. FIG. 4A shows a reciprocating traveling wire saw device,
FIG. 4B shows a one-way traveling wire saw device.

As shown in FIGS. 4 (a) and 4 (b), in a reciprocating traveling type wire saw device and a one-way traveling type wire saw device, a wire 11 is formed in a groove (see FIG. 4) formed on the surface of sheave wheels 12a, 12b, 12c. (Not shown).

In the case of the reciprocating traveling type wire saw device, the wire saw wire 11 is caused to travel under tension in either direction (the left-right direction in the drawing), and at the same time, is pressed against the ingot 14 to be processed placed on the support base 15. wear. At this time, the wafer is sliced by spraying the abrasive slurry 13 supplied from the abrasive slurry supply means 16 provided at the center of the sheaves 12a, 12b and 12c onto the surface of the ingot 14 to be processed.

In the case of a one-way traveling type wire saw device, the wire saw wire 11 is run under tension in one direction (right direction in the figure) and is moved to the workpiece ingot 14 placed on the support base 15. Press. At this time, in the running direction of the wire saw wire 11, a groove wheel (in the figure, a groove wheel 12
The abrasive slurry 13 supplied from the abrasive slurry supply means 26 provided between c) and the ingot 14 to be processed is applied to the surface of the wire for wire saw 11 to perform wafer slicing.

As described above, in the wire saw device,
In order to use the wire under tension, the wire needs to have a high tensile strength. For this reason, in general, a wire for a wire saw is a piano wire, an expensive special alloy steel wire, or an ultra-high-strength alloy wire whose metal crystal structure is adjusted (Japanese Patent Laid-Open No. 1-222
No. 814) and amorphous alloy wires are used.

At present, in the case of wafer slices using these wire saw wires, it is expected from the viewpoint of production cost that the yield is further improved by reducing the cutting margin. In order to reduce the cutting margin for improving the yield, it is necessary to reduce the wire diameter.

For this reason, various studies have been made to further reduce the diameter of a wire having a diameter of about 0.16 mm, which is conventionally used as a standard, and at the same time, it is desired to further increase the tensile strength level of the wire. ing.

[0013]

However, in the free abrasive slurry injection method, the slicing efficiency is low because the abrasive slurry is not stable in the wire saw.
In addition, the so-called "saw mark" caused by the momentary or partial lack of abrasive slurry (insufficient bite)
As a result, the yield and the production efficiency in the polishing step (mirror polishing step) after the wafer slice are reduced.

In the free abrasive slurry injection method, since the incorporation of abrasive grains is unstable and inefficient, various improvements have been made to improve the slice efficiency. For example, a spiral groove is formed on the surface of an elementary wire (wire) made of a single metal wire or a stranded wire (Japanese Utility Model Application No. 60-21620).
(See Japanese Utility Model Publication No. 61-137421).
On the surface of the elementary wire (wire) consisting of a single metal wire or stranded wire,
Diamond abrasive grains or SiC abrasive grains metal-supported (metal-bonded) by molten metal or plating (trade name; see Wiremond, Sumitomo Electric, March 132, 1988, pp. 118-122) , Etc. have been proposed.

Since the method (1) does not substitute the use of an abrasive slurry, the risk of generation of a “saw mark” is not completely eliminated.

In addition, this method is very expensive because of its complicated manufacturing process, and has not been widely used as a so-called industrial material.

In the case of the method (1), in order to avoid the problem that the wire is expensive and the production cost is high, there is a practical example as a so-called endless wire in which both ends of the wire are connected to form a ring. In addition, there is a problem that the strength of the wire connection portion is insufficient, and the abrasive effect is too strong, and the guides in the wire saw device are greatly worn.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an inexpensive wire saw wire having a high slice yield and a high slice efficiency.

[0019]

In order to solve the above-mentioned problems, a first aspect of the present invention is to use a high-strength metal wire as a wire, and apply abrasive grains on the surface of the wire other than a metal such as an organic material or an inorganic material. Supported by the above material.

According to a second aspect of the present invention, a high tensile strength non-metallic fiber or a fiber bundle thereof or a stranded wire thereof is used as a strand, and abrasive grains are carried on a surface of the strand by a material other than metal such as an organic material or an inorganic material. It was made.

A third aspect of the present invention is the wire for a wire saw according to the first and second aspects, wherein the organic material is a polyamideimide.

According to a fourth aspect of the present invention, there is provided the wire saw according to the first or second aspect, wherein the inorganic material is glass.

According to a fifth aspect of the present invention, the high tensile strength non-metallic fiber is a carbon fiber or a polyaramid fiber.
It is a wire for a wire saw as described.

According to the above construction, the high tensile strength metal wire is used as the element wire, and the abrasive grains are carried on the surface of the element wire by a material other than metal such as an organic material or an inorganic material. A high and inexpensive wire saw wire can be obtained.

[0025]

Embodiments of the present invention will be described below.

FIG. 1 is a cross-sectional view of the wire for a wire saw of the present invention.

As shown in FIG. 1, a wire saw wire 1
Is obtained by coating a binder 3 on the outer periphery of a strand 2 and dispersing abrasive grains 4 in the binder 3.

The wire 2 is not particularly limited, and examples thereof include a high tensile strength metal wire such as a brass-plated piano wire, a special alloy steel wire, an ultra-high strength alloy wire, and an amorphous alloy wire.

The binder 3 is not particularly limited as long as it is a material other than metal, such as an organic material such as a polyamide-imide resin and an inorganic material such as glass.

The abrasive grains 4 are not particularly limited, and include, for example, GC, alumina, silicon carbide and the like.

Next, the manufacturing method of the present invention will be described.

A solution in which the binder 3 is dissolved in a solvent is kneaded, and the abrasive grains 4 are dispersed in the solution.
This abrasive grain dispersion and solution is applied to the surface of a wire 2 made of brass-plated piano wire or the like, and thereafter, the wire 2 is baked by passing it through a heating furnace to produce a wire 1 for a wire saw.

The solvent is not particularly limited, and includes, for example, dimethylphenol.

In the wire for a wire saw of the present invention,
Since the abrasive particles 4 dispersed in a solvent containing the binder 3 are coated and baked on the surface of the strand 2, the solvent is evaporated and disappears at least on the surface of the wire saw wire 1 after baking. A very thin binder 3 is formed on the surface of the wire 1 for a wire saw,
The abrasive grains 4 may be partially exposed from the surface of the binder 3.

Since the abrasive grains 4 are carried on the surface of the wire for wire saw 1, the abrasive grains between the wire for wire saw 1 and an ingot to be processed (hereinafter, referred to as a work) during the wafer slicing using the free abrasive grain method. There is no danger of "saw marks" occurring if the slurry bites in instantaneously or partially.

That is, the wire 1 for a wire saw of the present invention.
Is a double-abrasive method of abrasive grains 4 on the surface and abrasive grains in the abrasive slurry.
The bite of the abrasive grains is remarkably improved, and the slicing efficiency can be improved.

Further, in the wire 1 for a wire saw of the present invention, since the bite of the abrasive grains at the time of wafer slicing is good, the wafer slice can be formed even if the pressing force on the work is not as strong as that of the conventional wire saw wire. It becomes possible. Therefore, the wire tension of the wire for a wire saw can be reduced, and the wire diameter can be reduced. Therefore, the cutting margin of the wafer slice can be reduced, and the yield can be improved.

Furthermore, since the wire 1 for a wire saw of the present invention is a wire with abrasive grains, depending on the material of the work,
Wafer slicing can be performed only with lubricating oil containing no abrasive grains without using an abrasive slurry. In other words, the production, maintenance, and management of the abrasive slurry in the conventional free abrasive grain slicing is unnecessary or greatly reduced, so that the working process at the time of wafer slicing can be simplified and the dirt working environment can be greatly reduced. Can be improved.

It is needless to say that the fixing force of the abrasive grains 4 to the binder 3 can be changed by appropriately selecting the material of the binder 3, and if it is compared with a general grindstone, a hard grindstone or a soft grindstone can be used. A grindstone can be appropriately selected. In addition, by appropriately selecting the size of the abrasive grains 4, optimal slicing can be performed according to the material of the work to be sliced and / or the purpose and conditions of slicing (for example, high-speed cutting or low surface roughness cutting). Needless to say,

Next, another embodiment of the present invention will be described.

In the wire for a wire saw of the present invention,
Although the high-strength metal wire is used as the strand, the wire for a wire saw according to another embodiment uses a high-strength nonmetallic fiber, a fiber bundle thereof, or a stranded wire thereof as the strand.

The high tensile strength non-metallic fiber is not particularly limited, and examples thereof include carbon fiber and polyaramid fiber.

It goes without saying that the wire for a wire saw according to the present embodiment also exerts the same effect as the wire for a wire saw of the present invention, and the material of the strand is the material of the work to be sliced and / or the purpose of the slice.・ Select appropriately according to the conditions.

[0044]

EXAMPLE A solution prepared by dissolving a binder made of a polyamideimide resin in dimethylphenol as a solvent is kneaded, and # 2000 GC abrasive grains are dispersed in the solution. This abrasive grain dispersion solution is 0.16 mm
Apply to the surface of the wire made of φ brass plated piano wire,
Thereafter, the element wire is baked by passing it through a heating furnace to produce a wire for a wire saw.

FIG. 2 shows a photograph of the surface of the wire for a wire saw in the example observed with a scanning electron microscope. The magnification of the microscope in the figure is 500 times, and one division is 6 μm.

As shown in FIG. 2, although the surface of the wire for a wire saw is coated with the binder, it can be seen that the GC abrasive grains are partially exposed from the surface of the binder.

The wire saw wire prepared in this example was set on a general-purpose wire saw device,
30 mmφ gallium arsenide compound semiconductor ingots were sliced at once. At this time, the target thickness of the wafer is 2 m
m.

As a result, the time required to complete a wafer slice using the wire for a wire saw of the present invention is as follows:
It was 50 to 70% when wafer slicing was performed while injecting abrasive slurry using a conventional wire saw wire, confirming improvement in slicing efficiency.

FIG. 3 shows a chart when the surface roughness of a part of the cross section of the wafer sliced with the wire for the wire saw in the embodiment is measured by a roughness measuring instrument. The vertical scale in the figure is the height of the wafer surface (μm; 0.5 μm per scale).
m), and the horizontal scale indicates the radial length of the wafer (mm;
(One scale is 5 mm).

As shown in FIG. 3, the surface roughness of a part of the cross section of the wafer was about 8 to 10 μm at the maximum.
This surface roughness can be further improved by optimizing the abrasive grain size and working conditions.

That is, the time required for slicing the wafer and the surface roughness of the cross section of the wafer are determined by the size and amount of the abrasive grains, the material of the binder, the slicing operation conditions, the material of the work, and the like. Can be further improved by combining.

[0052]

In summary, according to the present invention, the following excellent effects are exhibited.

(1) Since the penetration of the abrasive slurry into the work during wafer slicing is remarkably improved,
The slice efficiency can be improved and the slice time can be reduced.

(2) Since the tension applied to the wire can be reduced to a low level, the wire diameter can be reduced, and the slice yield can be improved.

(3) Depending on the material of the work, the wafer slicing can be performed only with the lubricating oil containing no abrasive grains without using the abrasive slurry, thereby simplifying the work process at the time of wafer slicing. And a dirty working environment can be improved.

(4) By appropriately selecting the abrasive grain size, the binder material, and the like, it is possible to obtain an optimal wire saw wire suitable for the work material, slicing conditions, and slicing purpose.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a wire for a wire saw of the present invention.

FIG. 2 is a photograph obtained by observing the surface of a wire for a wire saw in Example with a scanning electron microscope.

FIG. 3 is a diagram when a surface roughness of a part of a cross section of a wafer sliced with a wire for a wire saw is measured by a roughness measuring instrument in an example.

FIG. 4 is a perspective view of a conventional wire saw device.

[Explanation of symbols]

Reference Signs List 1 wire for wire saw 2 strand 3 binder (material other than metal such as organic material or inorganic material) 4 abrasive

Continued on the front page (72) Inventor Kazunori Suzuki 5-1-1 Hidaka-cho, Hitachi City, Ibaraki Prefecture Power Systems Research Laboratory, Hitachi Cable, Ltd.

Claims (5)

[Claims] 1. A wire for a wire saw, wherein a high tensile strength metal wire is used as a wire, and abrasive grains are carried on a surface of the wire with a material other than a metal such as an organic material or an inorganic material. 2. A high-strength non-metallic fiber or a fiber bundle thereof or a stranded wire thereof is a strand, and abrasive grains are carried on a surface of the strand by a material other than a metal such as an organic material or an inorganic material. And wire for wire saw. 3. The wire for a wire saw according to claim 1, wherein the organic material is a polyamideimide. 4. The method according to claim 1, wherein the inorganic material is glass.
And the wire for a wire saw according to claim 2. 5. The wire for a wire saw according to claim 2, wherein the high tensile strength nonmetallic fiber is a carbon fiber or a polyaramid fiber.