JP5452124B2 - Main roller for wire saw and wire saw - Google Patents

Description

  The present invention relates to a main roller for a wire saw and a wire saw.

In general, a wire saw that cuts an object to be cut with a wire fed by a main roller is used for manufacturing a semiconductor wafer (hereinafter simply referred to as a wafer). In such a wire saw, if the main roller is used for a long period of time, it is scraped off by the wire, so that work such as replacement of the main roller itself is required. Therefore, in order to reduce such work and improve productivity, a method for extending the life of the main roller has been studied (for example, see Patent Document 1).
In Patent Document 1, the main roller is made of a hard polyurethane resin, and the surface of the main roller is subjected to low-temperature oxygen plasma treatment to extend the life of the main roller.

JP-A-11-262853

By the way, as shown in FIG. 6 (A), the wire saw used in the configuration as in Patent Document 1 is formed of a stainless steel core 81 and a resin layer that is formed in a cylindrical shape by a polyurethane resin or the like and is covered with the metal core 81. 82 may be used. The wall thickness dimension E1 of the resin layer 82 is a wall thickness dimension (hereinafter referred to as a usable dimension) that can be used in a resin layer of a general main roller, and an area that cannot be used. It is set to a value (hereinafter referred to as a general set dimension value) that is a sum of the thickness dimensions (hereinafter referred to as unusable dimensions). In addition, the usable dimension is generally 5 mm to 10 mm.
Further, the wire 7 is pressed against the groove 821 provided in the resin layer 82. The wire 7 is provided in a spiral shape so that the three main rollers 8 are combined into one. For this reason, a pressing force acting in an oblique direction (direction indicated by arrow Y1) acts on the resin layer 82 with respect to the cylindrical axial direction (left-right direction in FIG. 6A).

However, when the wall thickness dimension E1 of the resin layer 82 is set to the general set dimension value, the resin layer 82 is obliquely crushed and deformed by the pressing force of the wire 7 as shown in FIG. Thus, there is a possibility that the period (life) until the quality of the wafer obtained by cutting deteriorates will be shortened.
Therefore, as shown in FIG. 7A, if the main roller 9 in which the core 81 is provided with a resin layer 92 thinner than the resin layer 82 (thickness dimension E2 is smaller than the thickness dimension E1), As shown in FIG. 7B, the deformation amount of the resin layer 92 is reduced and the life can be extended.
However, in the configuration as shown in FIG. 7A, the gap between the bottom of the groove 921 and the cored bar 81 is reduced, and even in a state where a wafer having a good quality can be obtained, the cored bar 81 as well as the resin layer 92 is cut by the wire 7. There is a risk that it will be.

  The objective of this invention is providing the main roller for wire saws which can aim at lifetime improvement easily, and a wire saw.

A main roller for a wire saw according to the present invention is a main roller for a wire saw that cuts an object to be cut with a wire, and is formed in a substantially cylindrical shape by a columnar or cylindrical roller base member and a material including a resin material. wherein comprising an inner resin containing layer covering the outer peripheral surface of the roller base member, and an outer resin layer is formed in a substantially cylindrical shape covering the outer peripheral surface of the inner resin layer containing and the wire is pressed against a resin material, a Te, The outer resin layer is formed to be softer than the inner resin-containing layer.

Here, as the object to be cut, any object that can be cut, such as a semiconductor single crystal ingot, crystal, glass, ceramics, quartz, or magnetic material, can be used. In addition, the roller base member may be made of metal such as stainless steel or resin. Furthermore, examples of the material used for the inner resin-containing layer include polyurethane, resin, glass fiber, and carbon fiber. Moreover, a polyurethane can be illustrated as a material used for an outer side resin layer.
According to the present invention, the outer resin layer that is softer than the inner resin-containing layer is provided on the outer peripheral surface of the inner resin-containing layer that covers the roller base member. The outer resin layer can be made thinner than the conventional resin layer while keeping the diameter dimension substantially the same. Therefore, since the deformation amount of the outer resin layer due to the pressing of the wire can be reduced, it is possible to lengthen the period during which the cutting object can be cut without degrading the quality. Even if the outer resin layer is shaved with a wire, the inner resin-containing layer is only shaved next, so that the roller base member can be prevented from being scraped and damaged.

In the main roller for a wire saw according to the present invention, it is preferable that the outer resin layer is provided so as to cover the end surface in the axial direction of the substantially cylindrical shape in the inner resin-containing layer.
Here, when exposed to the axial end face of the inner resin layer containing, will swell the inner resin-containing layer by slurry polishing liquid supplied during operation of the wire saw will touch the inner resin layer containing The life of the main roller may not be extended.
In contrast, in the present invention, by covering the axial end face of the inner resin layer containing an outer resin layer, it is possible to prevent the polishing liquid touches the inner resin containing layer, to prolong the life of the main roller Can do.

In the main roller for a wire saw of the present invention, the inner resin-containing layer is preferably formed of an inner resin-containing layer material mainly composed of glass fiber or carbon fiber.
According to this invention, since the main component of the inner resin layer containing a glass fiber or carbon fiber, compared to the configuration in which the main component resin such as polyurethane or resins, to increase the hardness of the inner resin layer containing it Can do. Accordingly, the inner resin-containing layer can be prevented from being scraped, and the roller base member can be prevented from being damaged.

In the main roller for a wire saw according to the present invention, it is preferable that the inner resin-containing layer is formed by spirally winding the tape-shaped inner resin-containing layer material around the roller base member.
According to the present invention, the tape-shaped inner resin-containing layer material is spirally wound around the roller base member, whereby the strength of the inner resin-containing layer can be increased and the roller base member can be prevented from being damaged.

In the main roller for a wire saw of the present invention, the inner resin-containing layer is preferably formed of polyurethane or resin.
According to this invention, for example, the inner resin-containing layer can be formed by an easy process of pouring polyurethane or resin into a mold provided around the roller base member and hardening it.

In the main roller for a wire saw of the present invention, the outer resin layer is preferably formed of polyurethane.
According to this invention, for example, the outer resin layer can be formed by an easy process in which polyurethane is poured into a mold provided around the inner resin-containing layer and hardened.

The wire saw according to the present invention includes the above-mentioned main roller for a wire saw.
According to the present invention, the life of the wire saw can be extended.

It is a mimetic diagram showing a schematic structure of a wire saw concerning a 1st embodiment of the present invention. It is a fragmentary sectional view of the main roller in the 1st and 2nd embodiments. It is a graph which shows the relationship between the hardness of the polyurethane by the hardness meter of Asker A in the said 1st Embodiment, and Young's modulus. It is explanatory drawing of the effect | action of the main roller in the said 1st Embodiment, (A) is sectional drawing which shows the state before a deformation | transformation of an outer layer, (B) is sectional drawing which shows the state after a deformation | transformation of an outer layer. is there. It is a perspective view which shows the manufacturing method of the inner layer in the said 2nd Embodiment. It is explanatory drawing of the effect | action of the conventional main roller, (A) is sectional drawing which shows the state before a deformation | transformation of the resin layer, (B) is sectional drawing which shows the state after a deformation | transformation of the resin layer. It is explanatory drawing of the effect | action of the other conventional main roller, (A) is sectional drawing which shows the state before a deformation | transformation of a resin layer, (B) is sectional drawing which shows the state after a deformation | transformation of the resin layer.

An embodiment of the present invention will be described with reference to the drawings.
[First Embodiment]
[Configuration of wire saw]
First, the configuration of the wire saw according to the first embodiment will be described. FIG. 1 is a schematic diagram showing a schematic configuration of a wire saw.
As shown in FIG. 1, a wire saw 1 is an apparatus for manufacturing a substantially disc-shaped semiconductor wafer (not shown) by cutting a single crystal ingot T as an object to be cut. The wire saw 1 is provided with a total of three main rollers 2 arranged in two on substantially the same horizontal plane, and one in the lower part between these two. Around these three main rollers 2, a wire 7 is wound spirally along the axial direction (perpendicular to the plane of FIG. 1). On both ends of the wire 7, wire reels 4 for feeding and winding the wire 7 through two guide rollers 3 are provided. Further, above the two upper main rollers 2 (hereinafter referred to as the upper main roller 2 as appropriate), nozzles 5 for supplying slurry-like abrasive liquid G to an intermediate position between the two upper main rollers 2 are respectively provided. Is provided.
The wire saw 1 rotates the main roller 2 and the guide roller 3 in the same direction, and winds the wire 7 fed out by one wire reel 4 by the other wire reel 4 between the two upper main rollers 2. By moving the single crystal ingot T downward while supplying the abrasive liquid G, the single crystal ingot T is cut to manufacture a semiconductor wafer.

[Configuration of main roller]
Next, a detailed configuration of the main roller 2 will be described. FIG. 2 is a partial cross-sectional view of the main roller.
As shown in FIG. 2, the main roller 2 includes a metal core 21 as a cylindrical roller base member made of stainless steel.
The main roller 2 includes an inner layer 22 provided to cover the cored bar 21. The inner layer 22 is formed in a cylindrical shape from polyurethane, for example, and is provided so as to cover the outer peripheral surface 211 of the core metal 21. The inner layer 22 is set to have a hardness of 97 degrees according to the Asker A hardness meter (hereinafter referred to as Asker A hardness meter) defined in the Japan Rubber Association Standard (SRIS).

  The main roller 2 includes an outer layer 23 provided to cover the inner layer 22. The outer layer 23 is formed in a cylindrical shape by polyurethane, for example, similarly to the inner layer 22, covers the outer peripheral surface 221 of the inner layer 22 and the end surfaces 222 at both axial ends of the inner layer 22, and is axially Are provided so that both end sides thereof are in close contact with the outer peripheral surface 211 of the cored bar 21. The outer layer 23 has a thickness D1 that can be used, and the hardness by the Asker A hardness meter is set to 90 degrees. Further, grooves 232 (see FIG. 4A) on which the wire 7 is pressed are provided at predetermined intervals on the outer peripheral surface 231 of the outer layer 23.

Here, the hardness of the inner layer 22 and the outer layer 23 is not limited to the above-described hardness, and may be any value as long as the outer layer 23 satisfies the condition that the outer layer 23 is softer than the inner layer 22. It is preferable that the hardness is 90 degrees to 95 degrees, and the hardness of the inner layer 22 is 95 degrees or more.
Here, the hardness of the polyurethane by the Asker A hardness meter and the Young's modulus have the relationship shown in FIG. That is, the outer layer 23 preferably has a Young's modulus of 215 GPa to 452 GPa, and the inner layer 22 preferably has a Young's modulus of 452 GPa to 1000 GPa.
When the Young's modulus of the outer layer 23 is less than 215 GPa, there is a problem that the deflection is large and stable high-speed operation is difficult due to low steel properties.
Examples of the method for forming the inner layer 22 and the outer layer 23 include a method in which polyurethane is poured into a mold provided around the cored bar 21 and the inner layer 22 and hardened.
The inner layer 22 has a thickness of 18 mm, and the outer layer 23 has a thickness of 12 mm. That is, the ratio of the thickness dimension between the inner layer 22 and the outer layer 23 is set to 6: 4.

[Operation of main roller]
Next, the operation of the main roller 2 will be described.
Here, a case where the following three conditions are satisfied will be described as an example.
The wall thickness dimension D2 of the inner layer 22 is substantially the same as the wall thickness dimension E2 of the resin layer 92 of the main roller 9 of the conventional example shown in FIG.
The total wall thickness D3 of the wall thickness D1 and the wall thickness D2 is substantially the same as the wall thickness E1 of the resin layer 82 of the main roller 8 of the conventional example shown in FIG.
The hardness of the outer layer 23 is substantially the same as the hardness of the resin layers 82 and 92.
4A and 4B are explanatory views of the operation of the main roller, in which FIG. 4A is a cross-sectional view showing a state before the outer layer is deformed, and FIG. 4B is a cross-sectional view showing a state after the outer layer is deformed.

As shown in FIG. 4A, a pressing force in the direction of arrow Y <b> 1 by the wire 7 acts on the groove 232 of the outer layer 23 of the main roller 2. And by this pressing force, as shown in FIG.4 (B), the outer side layer 23 is crushed diagonally and deform | transforms.
At this time, the total thickness D3 of the main roller 2 is substantially the same as the thickness E1 of the main roller 8, but the deformation amount of the outer layer 23 is smaller than that of the resin layer 82 and substantially the same as the resin layer 92. become. Further, since the inner layer 22 is harder than the outer layer 23, the deformation amount of the inner layer 22 that follows the deformation of the outer layer 23 can be minimized.

[Effects of First Embodiment]
In the first embodiment as described above, the following operational effects can be obtained.
(1) The main roller 2 includes an inner layer 22 that covers the outer peripheral surface 211 of the core metal 21, and an outer layer 23 that covers the inner layer 22 and is softer than the inner layer 22.
For this reason, since the outer layer 23 can be made thinner than the resin layer 82 while keeping the total thickness D3 of the main roller 2 substantially the same as the thickness E1 of the main roller 8, the deformation due to the pressing force of the wire 7 can be reduced. Therefore, the period during which the single crystal ingot T can be cut without degrading the quality can be lengthened. Moreover, since the inner layer 22 is provided between the core metal 21 and the outer layer 23, even if the outer layer 23 is shaved with the wire 7, the period until the core metal 21 is shaved can be lengthened. Breakage of the cored bar 21 can be suppressed.
Furthermore, since the above-described effect can be obtained while keeping the total thickness D3 of the main roller 2 substantially equal to that of the conventional art, the development to the conventional wire saw can be easily achieved. Further, in the conventional main roller 8, when the resin layer 82 is scraped by the usable dimension and its life is reached, it is necessary to remove the part corresponding to the unusable dimension and replace the entire resin layer 82. In the embodiment, when the outer layer 23 has been cut to a usable size and has reached the end of its life, it is only necessary to press-fit the outer layer 23 while leaving the inner layer 22, so that the maintenance cost of the main roller 2 can be reduced. .

  (2) The outer layer 23 is provided so as to cover the end surface 222 of the inner layer 22. For this reason, it is possible to prevent the abrasive fluid G from touching the inner layer 22 and to extend the life of the main roller 8.

[Second Embodiment]
Next, as a second embodiment, a main roller 2A used instead of the main roller 2 of the wire saw 1 of the first embodiment will be described.
[Configuration of main roller]
As shown in FIG. 2, the main roller 2A of the second embodiment has the same configuration as the main roller 2 except that an inner layer 22A is provided instead of the inner layer 22 of the main roller 2 of the first embodiment. Have.
Then, as shown in FIG. 5, the inner layer 22A has a thickness dimension of 18 mm by repeatedly winding a glass fiber tape 223A as a tape-shaped inner layer material on the outer peripheral surface 211 of the core metal 21 in a spiral manner. It is formed in a cylindrical shape. The glass fiber tape 223A is formed into a tape shape having a thickness dimension of 0.03 mm to 0.2 mm and a width dimension of 30 mm to 500 mm smaller than the inner layer 22A by impregnating glass fiber, which is the main component, with urethane. ing. The inner layer 22A is formed to be harder than the outer layer 23 whose hardness by a Rockwell M scale hardness meter (hereinafter referred to as a Rockwell M hardness meter) is set to 115 HRM and whose hardness by an Asker A hardness meter is 90 degrees. Has been.
That is, when the hardness of the inner layer 22A and the outer layer 23 is measured by an Asker A hardness meter that measures the hardness based on the amount of elastic deformation, the hardness of the outer layer 23 that is elastically deformed by the pushing force of the push needle is appropriately set. Although it can be measured, the hardness of the inner layer 22A that is not elastically deformed by the indentation force cannot be measured. On the other hand, when the hardness of the inner layer 22A and the outer layer 23 is measured by the Rockwell M hardness meter that measures the hardness based on the amount of plastic deformation, the hardness of the inner layer 22A that is plastically deformed by a test load can be appropriately measured. However, it is impossible to measure the hardness of the outer layer 23 that is elastically deformed without being plastically deformed by a test load.
From the above, it can be said that the inner layer 22A is harder than the outer layer 23 (the outer layer 23 is softer than the inner layer 22A).
The hardness of the inner layer 22A is preferably 115HRM to 120HRM as measured by a Rockwell M hardness tester.

[Effects of Second Embodiment]
In the second embodiment as described above, the following operational effects can be obtained in addition to the operational effects similar to (1) and (2) of the first embodiment.
(3) Since the inner layer 22A is formed of the glass fiber tape 223A, the hardness can be increased as compared with the inner layer 22 of the first embodiment made of polyurethane, and the core bar 21 can be prevented from being damaged.

  (4) The inner layer 22A is formed by spirally winding a tape-like glass fiber tape 223A. For this reason, the strength of the inner layer 22A can be increased, and the core bar 21 can be prevented from being damaged.

[Other Embodiments]
It should be noted that the present invention is not limited to the above embodiment, and various improvements and design changes can be made without departing from the scope of the present invention.
That is, the end surface 222 may be exposed without covering the end surface 222 of the inner layer 22 with the outer layer 23.
In the second embodiment, the inner layer 22 </ b> A may be formed by winding a glass fiber tape having the same width as the inner layer 22 </ b> A without moving in the axial direction of the cored bar 21.

Next, examples of the present invention will be described.
In this example, the relationship between the outer diameter dimension of the main roller and the main roller life (the number of lots when the main roller reaches the end of its life) was examined.

〔experimental method〕
First, a wire saw having the following configuration having the same configuration as the wire saw 1 of the above embodiment was prepared.
{Wire saw}
Komatsu NTC Corporation MWM-454B
{wire}
Japan Fine Steel Co., Ltd. 0.14 mm Saw Wire In addition, a main roller having the following specifications consisting of a single resin layer as shown in FIG. 6 (A) was prepared.
{Core}
Carbon steel for machine structure Diameter 135mm
{Resin layer}
Ester polyurethane, ether polyurethane

Then, using a main roller having a different outer diameter size, a process of cutting a single crystal ingot having a diameter size of 200 mm to a total length of 450 mm per cut while supplying the abrasive liquid # 2500 as one lot, Examined.
When the Warp value was less than Cpk1.33, it was determined that the main roller had reached the end of its life. Moreover, the case where the main roller life was 50 lots or less was defined as the short life.
The results are shown in Table 1 below.

As shown in Table 1, it was found that the smaller the thickness of the resin layer, the lower the probability of occurrence of short life, that is, the longer the life of the main roller.
Therefore, as in the present invention, the outer layer is made thinner than the resin layer while keeping the total thickness of the inner layer and the outer layer of the main roller substantially the same as the resin layer thickness of the conventional main roller. Thus, it was confirmed that the amount of deformation due to the pressing force of the wire can be reduced and the life of the main roller can be extended.

DESCRIPTION OF SYMBOLS 1 ... Wire saw 2, 2A ... Main roller 7 ... Wire 21 ... Core metal as roller base member 22, 22A ... Inner layer 23 ... Outer layer 223A ... Glass fiber tape as material for inner layer T ... Single as cut object Crystal ingot

Claims (7)

A main roller for a wire saw for cutting an object to be cut with a wire,
A cylindrical or cylindrical roller base member;
An inner resin-containing layer that is formed in a substantially cylindrical shape by a material including a resin material and covers the outer peripheral surface of the roller base member;
Comprising an outer resin layer is formed in a substantially cylindrical shape covering the outer peripheral surface of the inner resin layer containing and the wire is pressed against the resin material,
The main roller for a wire saw, wherein the outer resin layer is formed softer than the inner resin-containing layer. A main roller for a wire saw according to claim 1,
The main roller for a wire saw, wherein the outer resin layer is provided so as to cover the substantially cylindrical axial end surface of the inner resin-containing layer. A main roller for a wire saw according to claim 1 or 2,
The main roller for a wire saw, wherein the inner resin-containing layer is made of an inner resin-containing layer material mainly composed of glass fiber or carbon fiber. A main roller for a wire saw according to claim 3,
The main roller for a wire saw, wherein the inner resin-containing layer is formed by spirally winding a tape-like material for the inner resin-containing layer around the roller base member. A main roller for a wire saw according to claim 1 or 2,
The main roller for a wire saw, wherein the inner resin-containing layer is made of polyurethane or resin. A main roller for a wire saw according to any one of claims 1 to 5,
The main roller for a wire saw, wherein the outer resin layer is made of polyurethane.   The wire saw provided with the main roller for wire saws in any one of Claims 1-6.

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