JP2022093984A - Method of cutting workpiece - Google Patents

Abstract

To provide a method of cutting a workpiece that restrains the occurrence of fragments, chipping and cracks in a slice plate made by cutting of a workpiece.SOLUTION: A workpiece 1 is cut by a multi-wire saw 14 toward one surface from the other surface side to cut parts of the workpiece 1 and a slice table 2. The cutting is finished with a slice plate 1A made by cutting the workpiece 1 still bonded to the slice table 2, and the multi-wire saw 14 is moved toward the other surface side from one surface side of the workpiece 1(1A). A spacer 5 having a thickness that is 20 μm to 30 μm smaller than a diameter dimension of a wire of the multi-wire saw 14 is inserted into a range between the position of 2/6 and the position of 4/6 in terms of a ratio to the total length from the one surface of the workpiece (a plurality of slice plates 1A) bonded to the slice table 2 to the other surface of the workpiece opposite the one surface.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method for cutting a work piece, and in particular, a method for cutting a work piece, for example, using a wire saw to cut a work piece such as a synthetic quartz glass plate used for a large LCD mask substrate. Regarding.

Conventionally, for example, as shown in Patent Document 1, a plate-shaped synthetic quartz glass substrate has been cut out from a workpiece such as a synthetic quartz glass block using a wire saw.
Further, in the field of manufacturing wafer substrates such as silicon substrates and sapphire substrates, as shown in Patent Document 2, the workpiece to be ingot is adhered and fixed to a slice table, and this is set in a cutting machine such as a wire saw. After cutting, the adhesive is peeled off to produce a plate-shaped wafer substrate.

The method for manufacturing the wafer substrate will be described with reference to FIG. 7. First, the ingot 10 which is the workpiece is adhered and fixed to the slice table 11 by using the adhesive 12. Then, normally, the ingot 10 fixed to the slice table 11 is set in a cutting machine 13 such as a wire saw so that the ingot 10 is on the lower side and the slice table 11 is on the upper side.
The wire saw 14 is configured to be wound around three rollers 15 and moved by the rollers 15.

Then, by lowering the ingot 10, the ingot 10 is cut by the moving wire saw 14.
At this time, since the wire saw 14 bends, a part of the slice table 2 is also cut when the cutting end is approaching. After the cutting is completed, the wafer substrate (also referred to as a slice plate) 10A is in a state of hanging from the slice base 11 via the adhesive 12 (see FIG. 8).
Then, a plurality of wafer substrates (slice plates) 10A can be obtained by immersing the wafer substrate (slice plate) 10A hanging on the slice table 11 in a container such as a hot water bath or a solvent bath and peeling off the adhesive 12. ..

Japanese Unexamined Patent Publication No. 2017-160080 Japanese Unexamined Patent Publication No. 2014-96561

As shown in FIG. 8, the slice plate 10A from which the ingot 10 is cut is in a state of being hung from the slice table 11 via the adhesive 12, and then the wire saw 14 from which a part of the slice table 2 is cut is sliced. It is moved downward from the table 11 and removed from the slice plate 10A.

By the way, when cutting a work piece with a wire saw, a slurry containing an abrasive and a water-soluble or oil-based coolant is used.
Therefore, when the wire saw 14 is moved downward from the slice table 11 and removed from the slice plate 10A, as shown in FIG. 8, the slice plates 10A are connected to each other by the surface tension of the slurry adhering between the slice plates 10A. The phenomenon of sticking occurs.
Due to the sticking of the slice plates 10A to each other, stress is generated in the adhesive portion between the upper end portion S of the slice plate 10A and the slice base 11, and there is a problem that the upper end portion S of the slice plate 10A is chipped or cracked.

The present invention has been made to solve the above technical problems, and provides a method for cutting a work piece in which chipping, chipping, and cracks are suppressed in a sliced plate obtained by cutting the work piece. It is the purpose.

The method for cutting a work piece according to the present invention, which has been made to solve the above problems, includes a bonding step of adhering one surface of the work piece to a slice table with an adhesive, and a polishing agent after the bonding step. While supplying the slurry containing the coolant, the work piece is lowered and cut with a multi-wire saw from the other side of the work piece facing the one side of the work piece adhered to the slicing table. In the method of cutting a work piece having a cutting step, the work piece is cut from the other side of the work piece toward one surface with a multi-wire saw, and a part of the work piece and the slicing table is cut. The cutting is completed with the slice plate from which the workpiece has been cut still adhered to the slicing table, and the multi-wire saw is moved from one surface side to the other surface side of the workpiece. , 2/6 position with respect to the total length from the one surface of the workpiece (plurality of slice plates) adhered to the slice table to the other surface of the workpiece facing the one surface. It is characterized in that a spacer having a thickness of 20 μm to 30 μm smaller than the diameter dimension of the wire of the multi-wire saw is inserted within the range of the position of 4/6.

In the method for cutting a workpiece according to the present invention, after cutting a part of the workpiece and a slicing table, a multi-wire saw is directed from one surface side to the other surface side of the workpiece. Is moved, and a spacer is inserted and placed between the slice plates.
Since the spacers are arranged between the slice plates in this way, the sticking between the slice plates due to the surface tension of the slurry adhering between the slice plates is suppressed, and the stress generated at the adhesive portion between the slice plates and the slice table is suppressed. ..
As a result, chipping, chipping, and cracking at the upper end of the slice plate adhered to the slice table can be suppressed.

Further, as the spacer, a spacer having a thickness 20 μm to 30 μm smaller than the diameter dimension of the wire of the multi-wire saw is used. By sandwiching (holding) the spacer between the slice plates, chipping, chipping, and cracking of the slice plates can be suppressed.

On the other hand, when the thickness of the spacer is smaller than the diameter of the wire of the multi-wire saw by more than 30 μm, the spacer is not sandwiched (held) between the slice plates, and there is a problem that the spacer falls off. ..
On the other hand, when the thickness of the spacer is smaller than the diameter of the wire of the multi-wire saw by less than 20 μm, the spacer inserted and arranged may damage the surface of the slice plate.

Further, the spacer is a ratio of the total length from the one surface of the workpiece (plural slice plates) adhered to the slice table to the other surface of the workpiece facing the one surface. It is inserted and placed within the range of 2/6 position and 4/6 position.
By inserting and arranging the spacer within the range of the 2/6 position and the 4/6 position, by inserting and arranging the spacer in the one place, the slice plate due to the surface tension of the slurry. Sticking to each other is suppressed, and stress generated at the bonding portion between the slice plate and the slice table is suppressed.

Here, it is desirable to dissolve the adhesive in a state where the spacer is arranged between the slice plates and peel the slice plates from the slice table.
Since the slice plate is peeled off from the slice table with the spacer arranged between the slice plates, chipping, chipping, and cracking of the slice plate can be suppressed.

According to the present invention, it is possible to obtain a method for cutting a work piece in which chipping, chipping, and cracks are suppressed in a sliced plate obtained by cutting the work piece.

FIG. 1 is a schematic perspective view showing a bonding step of adhering a work piece to a slice table in one embodiment of the work piece cutting method according to the present invention. FIG. 2 is a schematic perspective view showing a cutting process for cutting a work piece in one embodiment of the work piece cutting method according to the present invention. FIG. 3 is a cross-sectional view showing a state in which the workpiece is cut. FIG. 4 is a cross-sectional view showing a state in which a spacer is inserted and arranged between slice plates after the workpiece is cut. 5A and 5B are schematic configuration views of spacers, where FIG. 5A is a front view and FIG. 5B is a side view. FIG. 6 is a schematic perspective view for explaining the insertion position of the spacer. FIG. 7 is a perspective view showing a cutting device for cutting a workpiece. FIG. 8 is a cross-sectional view showing a state in which the slice plates are stuck to each other due to the surface tension of the slurry adhering between the slice plates.

An embodiment of a method for cutting a workpiece according to the present invention will be described with reference to FIGS. 1 to 6.
Examples of the workpiece to which the cutting method according to the present invention can be applied include synthetic quartz glass blocks, sapphire ingots for LEDs, ingots such as SiC and GaN for power semiconductors, and silicon ingot blocks for solar cells. It can be widely applied to workpieces that can be cut using a multi-wire saw.

In this embodiment, a case where a synthetic quartz glass block is used as a workpiece will be described as an example. In this cutting method, a glass plate (sliced plate) is manufactured from synthetic quartz glass blocks through an bonding step, a cutting step, and a peeling step.

(Adhesion process)
First, the bonding process will be described. As shown in FIG. 1, for example, an acrylic adhesive 3 is interposed between the work table 4 and the carbon material slicing table 2, and the work table 4 and the carbon material slicing table 2 are adhered to each other.
Then, for example, an acrylic adhesive 3 is interposed between the carbon material slicing table 2 and the synthetic quartz glass block (ingot) 1, and the ingot 1 is adhered to the slicing table 2.
By obtaining this bonding step, the synthetic quartz glass block (ingot) 1 which is a workpiece, the slice table 2 and the work table 4 are integrated.

Although the carbon material slicing table has been described as an example of the slicing table, the present invention is not limited to the carbon material slicing table, and for example, a glass plate, a ceramic material, or the like can be used.
Further, although the acrylic adhesive has been described as an example of the adhesive, the present invention is not limited to the acrylic adhesive, and for example, an epoxy resin adhesive can be used.

(Cutting process)
Next, the cutting process will be described.
In this cutting step, as shown in FIG. 2, a cutting machine is used to cut the synthetic quartz glass block (ingot) 1 fixed to the slice table 2 so that the synthetic quartz glass block 1 is on the lower side and the slice table 2 is on the upper side. Set to 13.
As the cutting machine 13, as shown in FIG. 7, a commonly used multi-wire saw in which an extra-fine wire 14 is wound around a plurality of rollers 15 at a constant pitch can be used. The invention is not particularly limited to this.

Then, as shown by the arrow in FIG. 2, the synthetic quartz glass block (ingot) 1 is cut by the moving multi-wire saw 14 by lowering the synthetic quartz glass block (ingot) 1. For the cutting, a slurry containing an abrasive and a water-soluble or oil-based coolant is used.
At this time, the synthetic quartz glass block (ingot) 1 is lowered, completely passed through the synthetic quartz glass block (ingot) 1, and cut to a part of the slice table 2 (see FIG. 3). This is because the wire saw 14 bends, so that a part of the slice table 2 is cut in order to completely cut the synthetic quartz glass block (ingot) 1.
Then, after the cutting is completed, the plurality of slice plates 1A are in a state of hanging from the slice table 2 via the adhesive 3 as shown in FIG.

Then, as shown by the arrow in FIG. 3, the wire saw 14 is moved downward from the slicing table 11 and removed from the lower end of the slicing plate 1A.
At this time, as shown in FIG. 8, the sliced plates after cutting stick to each other due to the surface tension of the slurry adhering between the slice plates, and stress is generated in the bonded portion of the slice plate with the slice table, and the upper end portion of the slice plate is formed. In addition, there is a risk of chipping or cracking.
Therefore, as shown in FIG. 4, when the wire saw 14 is removed from the lower end of the slice plate 10A, the spacer 5 is inserted and arranged between the slice plates 1A to prevent the slice plates 1A from sticking to each other.

The spacer 5 may be any as long as it can be inserted and placed between the slice plates 1A, but the spacer 5 has a hardness that allows the thickness to be accurate (difficult to wear), is easy to insert, and can be used repeatedly. Is desirable, and thin plates made of SUS, iron, aluminum, titanium or resin are suitable. Among them, SUS, which has good thickness accuracy, excellent wear resistance, and is inexpensive, is most preferable.
For example, as shown in FIG. 5, a long plate-shaped spacer 5 having a thickness t and a length L can be used.
Specifically, the length L is determined in consideration of the length inserted between the slice plates 1A, and when the spacers are inserted and arranged between the slice plates 1A, the spacers do not protrude from the slice plates 1A. Any length is fine. Further, the thickness t is preferably determined according to the wire diameter because the cutting allowance (slice plate gap after cutting) changes depending on the wire diameter, and is 20 μm to 30 μm, which is larger than the diameter dimension of the wire of the multi-wire saw. It has a small size, preferably 40 mm to 100 mm.

If the thickness t of the spacer 5 is too thick, the gap between the slice plates may be widened when the spacer 5 is inserted, stress may be generated on the adhesive surface, and chipping or cracks may occur. In addition, there is a problem that the surface of the slice plate is scratched.
On the other hand, when the thickness t of the spacer 5 is thin, there arises a problem that the spacer cannot be held in a fixed position (it is not sandwiched by the slice plate).

Further, as shown in FIG. 6, the spacer 5 is a ratio of the total length T from one surface of the synthetic quartz glass block (ingot) 1 adhered to the slice table 2 to the other surface facing the one surface. Then, insert and place it within the range of 2/6 position and 4/6 position.
Spacers 5 may be inserted and arranged at a plurality of locations in the gap between the slice plates 1A, but if the number of slice plates 5 is large, it takes time to insert and arrange the spacers 5, which is preferable because workability is poor. do not have.
When the spacer 5 is inserted and placed within the range of the 2/6 position and the 4/6 position, the sticking between the slice plates 1A can be suppressed at this one place, so that the insertion and placement work can be performed. preferable.

(Peeling process)
After the cutting step, the slice plate 1A is peeled from the slice table 2 to obtain a slice plate.
In this peeling step, the slice plate 1A hanging from the slice table 2 via the adhesive 5 is placed in a holder, and the holder is immersed in a container such as a hot water bath or a solvent bath.
Then, the adhesive is melted and the slice plate 1A is peeled off from the slice table 2. Then, by peeling off the adhesive and pulling up the holder from the container, a plurality of slice plates are obtained.

The method for cutting the workpiece according to the present invention will be further described with reference to Examples and Comparative Examples.
(Example 1)
Synthetic quartz glass blocks, which are workpieces, are processed with a multi-wire saw, using a slurry containing silicon carbide abrasive grains and coolant, with an iron wire having a wire diameter of 0.32 mm, a linear speed of 80 m / sec, and a cutting speed of 20. By cutting under the condition of 0.0 mm / hour, 10 plate-shaped synthetic quartz glass substrates (sliced plates) having a thickness of 10.30 mm, a length of 525 mm, and a width of 805 mm were obtained.
After cutting, remove the multi-wire saw and insert a spacer with a thickness of 0.295 mm, a width of 13 mm, and a length of 75 mm at one place at the middle point of the cutting length (3/6 position) of each slice plate to a depth of about 50 mm. Inserted and placed. Then, the chipping of the slice plate and the occurrence rate of cracks were evaluated. The results are shown in Table 1.

(Example 2)
The evaluation was carried out in the same manner as in Example 1 above except that the thickness of the spacer was 0.290 mm and the position where the spacer was inserted and placed was 2/6 of the cutting length of each slice plate. The rate of chipping and cracking of sliced plates was evaluated. The results are shown in Table 1.
(Example 3)
The evaluation was carried out in the same manner as in Example 1 above except that the thickness of the spacer was 0.300 mm and the position where the spacer was inserted and placed was 4/6 of the cutting length of each slice plate. The rate of chipping and cracking of sliced plates was evaluated. The results are shown in Table 1.

(Comparative Example 1)
In the same manner as in Example 1, it was cut with a multi-wire saw to obtain 10 plate-shaped synthetic quartz glass substrates (sliced plates) having a thickness of 10.30 mm, a length of 525 mm, and a width of 805 mm.
After that, unlike Example 1, no spacer was inserted. Then, the chipping and crack occurrence rate were evaluated. The results are shown in Table 1.

As shown in Table 1, the occurrence rate of chipping and cracks was 8.1% when the spacer was not inserted, whereas it was 3.7% when the spacer was inserted, and the chipping and crack occurrence rate decreased. Was confirmed.

(Comparative Example 2), (Comparative Example 3)
As shown in FIG. 6, the insertion position of the spacer was changed to the 1/6 position (Comparative Example 2) and the 5/6 position (Comparative Example 3), and the chipping of the slice plate and the occurrence rate of cracks were evaluated. .. The results are shown in Table 1. As shown in Table 1, at the 1/6 position and the 5/6 position, the slice plate was not chipped and the crack prevention effect was not obtained.

(Comparative Example 4)
Next, in the same manner as in Example 1, the synthetic quartz glass block was cut to obtain 10 plate-shaped synthetic quartz glass substrates (sliced plates), and then the multi-wire saw was pulled out to obtain a thickness of 0.31 mm. A spacer having a width of 13 mm and a length of 75 mm was inserted and placed at one place at the midpoint of the cutting length (position of 3/6) of each slice plate to a depth of about 50 mm. Then, the chipping of the slice plate and the occurrence rate of cracks were evaluated.
That is, the thickness of the spacer was set to 0.31 mm, which is 10 μm smaller than the wire diameter. However, although this spacer could be inserted between slice plates, the experiment was discontinued because it was in a tight state during insertion and there was a risk of chipping, cracks and scratches due to insertion.

(Comparative Example 5)
Next, in the same manner as in Example 1, the synthetic quartz glass block was cut to obtain 10 plate-shaped synthetic quartz glass substrates (sliced plates), and then the multi-wire saw was pulled out to obtain a thickness of 0.28 mm. A spacer having a width of 13 mm and a length of 75 mm was inserted and placed at one place at the midpoint of the cutting length (position of 3/6) of each slice plate to a depth of about 50 mm. Then, the chipping of the slice plate and the occurrence rate of cracks were evaluated.
That is, the thickness of the spacer was set to 0.28 mm, which is 40 μm smaller than the wire diameter. However, the experiment was discontinued because the spacer slipped off and could be held in the 3/6 position.

1 Synthetic quartz glass block (workpiece)
1A Slice plate 2 Slice stand 3 Adhesive 4 Work table 5 Spacer

Claims (2)

After the bonding step of adhering one surface of the work piece to the slice table with an adhesive and the bonding step, the work piece is lowered and adhered to the slice table while supplying a slurry containing an abrasive and a coolant. In a method for cutting a workpiece, which comprises a cutting step of cutting with a multi-wire saw from the other surface side of the workpiece facing the one surface of the workpiece.
The work piece is cut from the other side to one side with a multi-wire saw to cut a part of the work piece and the slicing table, and at the same time.
The cutting is completed with the slice plate from which the workpiece has been cut still adhered to the slicing table.
The multi-wire saw is moved from one surface side of the workpiece to the other surface side, and from the one surface of the workpiece (plurality of slice plates) adhered to the slice table, the one The thickness is 20 μm to 30 μm smaller than the diameter dimension of the wire of the multi-wire saw within the range of 2/6 position and 4/6 position as a ratio to the total length to the other surface of the workpiece facing the surface. A method for cutting a workpiece, which comprises inserting a wire spacer. The method for cutting a workpiece according to claim 1, wherein the adhesive is melted in a state where the spacer is arranged between the slice plates, and the slice plates are peeled off from the slice table.

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