JPH04169204A - Cutting method and apparatus by multiwire saw - Google Patents

Abstract

PURPOSE:To recover wafers in an extremely efficient manner by supporting and fixing the dummy material bonded to a work by a holder of a recessed and protruding system of fits and cutting the work in such a state that the holder is fixed to a work push-up stand until the dummy material is perfectly cut and subsequently pulling out wafers from the holder. CONSTITUTION:The dummy material 18 bonded to a work 6 is supported on a holder 15 of a recessed and protruding system of fits to be fixed thereto in a freely detachable manner by screws 11 and the holder 15 is cut by wires 4 up to a position perfectly cutting the dummy material under the work 6. By this method, the cut pieces of the dummy material bonded to wafers 6-1 are fitted in the holder 15 and, therefore, the wafer 6-1 having the cut pieces bonded thereto can be taken out of the holder 15. As mentioned above, the mounting of the work 6 and the recovery of the wafers 6-1 can be performed in an extremely efficient manner.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a multi-wire saw for cutting brittle materials such as semiconductor materials, magnetic materials, and ceramics into a large number of thin wafers using wires. The present invention relates to a cutting method and an apparatus for making it possible to take out a wafer easily, quickly and efficiently after cutting is completed.

Conventional Technology A multi-wire saw used to cut ingots of brittle materials such as semiconductor materials into wafer shapes presses an object to be cut (hereinafter referred to as the "workpiece") against a row of wires hung in multiple rows at a predetermined pitch. This is a device that moves a wire and a workpiece relative to each other while pouring a grinding liquid containing abrasive grains (hereinafter referred to as an abrasive liquid), and cuts the workpiece by grinding action.

Figure 11 shows an example of the cutting section of a general multi-wire saw, in which three groove rollers (1) are rotatably held.
(2) One wire (4) is wound around a large number of grooves carved on the outer peripheral surface of (3), and the wire rows (5) are wound at a predetermined pitch.
) is formed, and while running this wire row, the workpiece lifting table (10) is pushed up while supplying abrasive liquid from the nozzle (7) to the contact area between the workpiece (6) and the wire row (5),
In this method, the workpiece (6) is gradually cut by a grinding action, and the workpiece (6) is attached to the base (9) with an adhesive via a dummy plate (8).

That is, a dummy plate (
8) and attach this dummy board to the base (9) with adhesive.
The base (9) is attached to the workpiece lifting platform (10
) is removably attached with a screw (11).

When using an adhesive as a means of fixing the workpiece, it goes without saying that the adhesive must have adhesive strength that can withstand the grinding force caused by the running of the wire row (5), and epoxy-based adhesives are usually used. , wax, etc. are used.

FIG. 12 (AXB) is an enlarged view of the cutting section of the wire saw, and the pushing up of the workpiece (6) continues until the wire row (5) cuts into the dummy plate (8). ) is cut into a number of wafers (6-1). Moreover, at this time, the wire row (5) is located in the middle of the dummy plate (8) as shown in FIG. 12(B), and the abrasive grains (12) are present between the cut wafers. It is in a full state.

The cut wafer (6-1) is taken out using a wire saw, and conventional methods for taking it out include the following methods.

The first method is to cut the wire row (5) shown in FIG. 12(A) on both sides of the workpiece (6), loosen the screws (11), and push the base (9) onto the push-up table (10). In this method, the wires (4) remaining in the workpiece (6) are pulled out one by one.

The second method is to remove the wire (4) from the workpiece (6) by running the wire (4) while keeping the push-up table (10) stopped, and remove the base (9) from the push-up table (10). It is.

The third method is to start from the state shown in FIG.
) while running at low speed, lower the push platform (10),
This is a method in which the wire row (5) is pulled out above the workpiece (6) and then the base (9) is removed from the push-up table (10).

A fourth method is to wash and remove abrasive grains (12) stuck between wafers while leaving the wire array (5) in the dummy plate (8), as shown in Japanese Patent Application Laid-Open No. 12576/1983. death,
This is a method in which the wafers (6-1) are broken off one by one from the edge using a suction pad.

The fifth method, as shown in Japanese Unexamined Patent Publication No. 182761/1983, is to grip both sides of the workpiece (6) along its entire length in the state shown in FIG. 12(A), and tighten the screws (11
), and while the wire row (5) is traveling, the base (9) is gradually slid by a separate drive device (not shown), and the dummy plate (8) is cut across by the wire row (5). This is a method of taking out all wafers at once.

Problems to be Solved by the Invention However, the first to fifth methods have the following problems.

The first method is convenient when the wire is disposed of after being cut once, but results in a large loss when the wire is only slightly damaged and can be reused. Another problem is that it takes a lot of man-hours to set the wire on the wire saw again.

The second method allows the wire to be reused, but has the disadvantage that winding takes time if there is a large amount of wire remaining at the time the cutting is completed. Also, like the first method, there is a drawback that it takes a lot of man-hours to set the wire on the wire saw again.

The third method has the advantage that the wire row remains in the wire saw, so another workpiece can be cut subsequently, and the wire saw can be operated efficiently, but the workpiece is lowered. During the process, saw marks may be created on the wafer surface.

In other words, there is no problem if the cut surface of the wafer is sufficiently flat and vertical, but if these conditions are not met, the wire row will rub against the cut surface and the workpiece will descend, resulting in saw marks. It is. Depending on the severity of the saw mark, the wafer may have to be discarded.

In the fourth method, although there is no concern about saw marks, if the workpiece is fragile, there is a possibility that the wafer itself may be broken without being broken at the position of the dummy plate. Another drawback is that when there are a large number of wafers, it takes time to take out the wafers.

Note that the first to third methods also require a step of breaking off the work pieces one by one from the group of wafers removed from the wire saw, and like the fourth method, there are problems with wafer breakage and man-hours. Needless to say.

The fifth method is efficient because all the wafers are taken out at once, but there are problems in that the device is complicated and the manufacturing cost is high.

This invention was made in order to solve the above-mentioned problems related to taking out wafers after cutting with a wire saw, and it is possible to very efficiently collect wafers after cutting with a relatively simple means, and to improve the operation of a multi-wire saw. The purpose of this paper is to propose a cutting method and device that can improve the cutting rate.

Means for Solving the Problems The gist of the present invention is to support a dummy material adhered to a workpiece with a holder of a concave-convex fitting method, fix it with screws, etc., and fix the holder to a workpiece lifting table with screws, etc. This is a cutting method in which the wafer is cut until the dummy material is completely cut, and then the wafer with the cut pieces of the dummy material attached is removed from the holder. The boulder is supported by the workpiece and fixed with screws, etc., and cutting is performed with the boulder fixed to the workpiece lifting table. After cutting until the workpiece is completely cut,
This is a cutting method in which the wafer is removed from the holder.

An apparatus for carrying out the method of the present invention includes a concave-convex fitting type holder for supporting a dummy material bonded to a workpiece, and a screw or bolt for fixing the dummy material screwed onto the side surface of the holder, It has a structure that is fixed to the workpiece lifting table with adhesive etc., and also includes a concave-convex fitting type holder that supports the workpiece without a dummy material, and a workpiece fixing device that is fixed to the holder with screws, bolts, etc. It has a face plate, and has a structure in which the holder is fixed onto a workpiece lifting table by adhesive or the like.

In the case of a method in which the dummy material glued to the workpiece is supported by a concave-convex fitting type holder and removably fixed with screws, the workpiece may become unstable due to the force acting on the workpiece during cutting in the direction of wire travel. It doesn't move.

In addition, when the holder is cut to a position where the wire completely cuts the dummy material under the workpiece, the cut pieces of the dummy material glued to the wafer are supported by the holder groove wall, and there is abrasive grain between the wafers. The wafer will not fall over because it is full of gas.

Since the cut pieces of the dummy material adhered to the wafer are only fitted in the holder in a concave and convex manner, the wafer to which the cut pieces of the dummy material are attached can be taken out from the holder. In that case, first loosen the tightening screws, remove the end of the workpiece to which the end of the dummy material is attached, and either collect the remaining wafers all at once or start from the end and use the wafers with the dummy material cut pieces attached. Remove it from the holder.

Since the wire rows fit into the cut grooves of the used holder as they are, the same holder can be used to repeatedly cut the workpiece, making it possible to load the workpiece onto the wire saw and take out the wafer extremely efficiently.

In the case of a method in which the workpiece is directly supported by a concave-convex fitting type holder without using a dummy material, in order to fix both end faces of the workpiece, for example, a face plate is fitted internally into the holder recesses on both sides of the workpiece, and the face plate is While touching both ends of the workpiece, fix it to the holder with screws, etc.

The sides of the workpiece are supported by the side walls of the holder, so
The workpiece will not move unstable due to the force of the wire.

Additionally, if the wire completely cuts the workpiece and cuts into the holder, the edge of the wafer will be supported by the uncut portion of the sidewall of the workholder, and the space between the wafers will be filled with abrasive grains, so the wafer will fall over. Never.

To remove the wafers, after removing the face plate for fixing the workpiece, the wafers are removed from the used holder either all at once or sequentially from the end.

If the same cutting is to be repeated, all that is required is to set a new workpiece in the used holder and attach the face plate, making it possible to load the workpiece and take out the wafer extremely efficiently.

Embodiment Example 1 Figures 1 to 6 show an example of an apparatus for carrying out the cutting method using dummy material in the present invention.
The figure shows the workpiece and dummy material, Figure 2 shows the holder that supports the workpiece with the dummy material using a concave-convex fitting method, Figure 3 shows the assembly of the workpiece with the dummy material and the holder set on a wire saw, and Figure 4 shows Figure 5 shows the state in which the wire has cut into the dummy material under the workpiece to the point where it is completely cut. Figure 5 shows the state in which the wire row has been pulled out from the holder after the wafer has been removed by the wire saw. Figure 6 shows the holder with a split structure and the dummy. Each figure shows the state in which an assembled workpiece with material is set on a wire saw.

In Figure 1, Figure (A) is a front view and Figure (B) is a side view, showing a state in which a dummy material (18) of a desired thickness, which is longer than the workpiece, is adhered to the lower surface of the workpiece (6) with adhesive. show.

The width of the dummy material (18) may be shorter than the width of the workpiece.

The dummy member (18) is made of ceramics, glass, etc. that can be easily cut with a wire saw, similar to the dummy plate (8) of the conventional method described above.

In Figure 2, Figure (A) is a front view of the holder and Figure (B) is a front view of the holder.
) is a side view of the same as above, and the holder (15) is attached to the dummy material (
18) has a recessed portion (15-1) that can be fitted into the recessed portion without a gap, and dummy material fixing screws (16) are screwed into both side end portions.

In this invention, the holder is also cut halfway with the wire, so it is desirable that the holder be made of a material that is easy to cut, such as ceramics or glass, just like the dummy material.

For the screw (16), the dummy material is the concave part (15-1) of the holder.
The purpose of the tightening is to fix it so that it does not move inside, and it is placed at the end to prevent it from being cut by the wire. Note that the method of fixing the dummy material is not limited to this method.
Other means are acceptable as long as they meet the above objectives.

In Fig. 3, the holder (15) is bonded to the base (9) with adhesive, and the base (9) is connected to the workpiece lifting platform (1).
0) is tightened and fixed with a screw (11).

When cutting the workpiece (6), a row of wires (5) stretched at predetermined intervals is run, and cutting is performed while supplying an abrasive liquid as shown in FIG.

A force in the wire advancing direction is applied by the wire row (5) to the workpiece (6) being cut, but the dummy material (18) is fitted into the holder (15) without any gaps, and the screws ( 16), so it will not move unstablely due to the force of the wire row.

In FIG. 4, the cut piece of the dummy material (18) is supported by the uncut portion of the holder side wall, and the wafer (6
-1) Since the gap is filled with abrasive grains, the wafer will not fall over.

When taking out the wafer, after stopping the wire running in the state shown in Figure 4, first loosen the dummy material fixing screws (16) and remove the wafers (6-1) attached to both ends of the dummy material. The remaining wafers are removed from the holder (15), and the wafers to which the cut pieces of dummy material are attached are successively removed from the holder (15) from the end. At this time, since the space between the wafers is filled with abrasive grains, it is possible to take out the wafers in units of several dozen or in batches, which is efficient.

After cutting is completed and all wafers are taken out, the push-up table (10) is lowered to remove the wire array (5) from the used holder (15), as shown in FIG. If the workpiece is to be cut again from this state, the adhesive of the workpiece and dummy material shown in FIG. 1 is attached to the used holder (15) remaining on the base (9).

The holder (15) has a cut groove (15-2) during the first cutting.
) is formed, but since the wire row (5) enters the cut groove (15-2) as it is, there is no problem at all, and the same is true when cutting is repeated. Removal can be performed extremely efficiently.

Although the grooves of the holder (15) are formed in the first cutting, it is also possible to form the same grooves in the holder in advance.

Although the holder (15) shown in FIG. 2 has an integral structure, it does not necessarily have to be an integral structure, and may have a divided structure. Figure 6 shows an example of this, in which the dummy material (18) is supported by being sandwiched between the left and right split holders (15-3).In this case, the split holder (15-3) is attached to the base. After fixing with adhesive to (9), the dummy material (18) is tightened and fixed with screws (16).

Embodiment 2 Figures 7 to 9 illustrate a method of directly supporting and cutting a workpiece with a holder without using a dummy material.
The figure shows a concave-convex fitting type holder that supports a workpiece. Figure (A) is a front view, Figure (B) is a partially cutaway side view, and Figure 8 shows the workpiece and holder assembly set on a wire saw. Figure (A) is a front view, Figure (B) is a side view, Figure 9 is a diagram showing the wire cut to the holder under the workpiece, and Figure (A) is a front view. , Figure (B) is a side view, and Figure 10 is a front view showing a state in which the holder with a split structure is used and is inserted into a wire saw.

That is, the holder (25) directly supports the workpiece (6).
) is a box-shaped item into which a workpiece is fitted without any gaps, and consists of a main body (25-1) with a concave cross-section and a face plate (20) that is fitted into both ends of the main body and can be attached and detached with screws (21). It is configured.

When using this holder to set the workpiece (6) on the wire hiso, as shown in Figure 8, first the workpiece (6)
6) into the holder (25), and attach the face plates (
20) is fitted into the base (9) without any gap and tightened and fixed with the screw (21), and then the bottom surface of the holder (25) is adhesively fixed to the base (9) by a method such as gluing.

When cutting the workpiece, the wire row (5) is made to run and cutting is performed while supplying abrasive liquid, as in the case of FIG. 3 above.

The workpiece (6) being cut has a wire row (5
) Therefore, a force is applied in the wire advancing direction, but the workpiece (6
) is fitted and supported by the holder (25) on both sides without any gaps, so it will not move unstablely due to the force of the wire array.

When the wire row (5) completely cuts the workpiece (6) and cuts into the bottom plate of the holder (25), the wire stops running, but in this state the edge of the wafer (6-1) is cut into the holder (25). Since the wafers are supported by the uncut portions of 25) and the spaces between the wafers are filled with abrasive grains, the wafers do not fall over.

When removing a wafer, first loosen the screws (21) and remove the face plate (20) of the holder, then remove the wafer (
6-1). At that time, since the space between the wafers is filled with abrasive grains, the wafers are processed in units of tens of wafers or -
It can also be taken out in bulk. Note that if it is difficult to take out the wafer due to the viscosity of the abrasive grains, the wafer may be taken out while washing the abrasive grains with a cleaning liquid such as kerosene.

When the wafer removal is completed, as shown in FIG. 5, the push-up table (10) is lowered to remove the wire row (5) from the used holder. When cutting a workpiece again from this state, it is only necessary to insert a new workpiece into the used workpiece holder and attach the face plate, and workpiece mounting can be done extremely efficiently.

Also, in the case of this holder, the grooves to be formed during the first cutting may be formed in advance.

Furthermore, although the work holder mentioned above has an integral structure, the 10th
As shown in the figure, similar to the one shown in FIG.
A divided holder (25-2) is formed, the workpiece (6) is supported by this divided holder, and after gluing the divided holder to the base (9), the face plate (20) is tightened with screws (21). It may be fixed.

In addition, although the above-mentioned Example 1.2 shows a workpiece with a rectangular cross section, it goes without saying that the present invention is not limited to a rectangular cross section and can be applied to any other arbitrary cross-sectional shape. For example, in the case of a workpiece with a circular cross section, a dummy material having a curved surface equivalent to the curvature of the outer peripheral surface of the workpiece may be bonded to the workpiece, and the dummy material may be mounted on a holder. Similarly, if a workpiece with a circular cross section is to be mounted directly on the holder, the workpiece holder of the holder should have a curved surface equivalent to the curvature of the workpiece, and the face plate of the holder should be formed so as to follow the surface of the workpiece holder. .

Example 3 A ceramic dummy material with a width of 70 mm, a length of 250 mm, and a center thickness of 20 mm is adhered to a silicon ingot (work) with a diameter of 150 mm and a length of 205 mm, and the dummy material is placed in a ceramic holder shown in FIG. Fit and fix with screws and attach it to the push-up stand, and the diameter is 0.16 m.
While running a wire row consisting of wires of length 1.05 mm stretched at a pitch of 1.05 mm, an abrasive liquid containing green carporundum #600 abrasive grains was supplied, the push-up table was raised, and the workpiece and dummy material were cut. 1 wafer with a thickness of 0.8 mm
I got 90 pieces. The time required from cutting the workpiece to taking out all the wafers was 8 minutes.

On the other hand, for comparison, the same workpiece was cut using the conventional method of gluing a dummy material to the base. At that time, after cutting the workpiece, the wire stops running when it cuts halfway into the dummy material, and then the abrasive grains between the wafers are washed away with kerosene, and the wafers are cut one by one using a suction pad starting from the edge. I picked it up and broke it off. The time required for this wafer breaking operation was 70 minutes.

Therefore, it can be seen that the method of this invention dramatically improves the efficiency of taking out wafers.

Example 4 A 100 mm square, 210 mm long quartz ingot was fitted into the glass work holder shown in Fig. 7, both ends were fixed with face plates and screws, and wires with a diameter of 0.2 mm were stretched at a pitch of 2 mm. The workpiece was cut using the same abrasive liquid as in Example 3 while running the wire row, and after cutting, the face plate was removed to obtain 100 wafers each having a thickness of 1.7 mm.

The time required to take out all the wafers after cutting the workpiece was 6 minutes.

On the other hand, for comparison, the same workpiece was cut using the conventional method of gluing a dummy material to the workpiece and cutting it. At that time, a glass dummy plate is glued to the base of the workpiece, and when the wire is cut halfway into the dummy plate, the push-up is stopped.
Lower the push platform while slowly running the wire,
After the Y row was separated from the workpiece, the base was removed from the push-up table, and the wafer was broken off in order from the end.

This method requires two hours to remove all wafers, and
In the process of lowering the push-up table, saw marks were generated by the wire on the cut surface of some wafers, and wafers with severe saw marks had to be discarded.

Therefore, it is clear that according to the method of the present invention, not only the number of man-hours for taking out wafers is significantly reduced, but also wafers of good quality can be obtained.

As described in detail, according to the method and apparatus of the invention,
It is possible to extremely efficiently take out a wafer after cutting a workpiece with a multi-wire saw, and it is also possible to repeatedly cut a workpiece with the same work holder, so the operating rate of the multi-wire saw can be significantly improved. In addition, the device has a relatively simple structure and has the advantage that it not only requires low equipment costs but also can be easily applied to existing wire saws, making it extremely effective in wafer manufacturing.

[Brief explanation of drawings]

1 to 6 are diagrams showing an example of the configuration of an apparatus for carrying out the cutting method using a dummy material according to the present invention. FIG. 1 shows an assembled product of a workpiece and a dummy material, and FIG. Figure 2 shows a front view, Figure (B) is a side view, Figure 2 shows a work holder that supports a workpiece with a dummy material using a concave-convex fitting method, Figure (A) is a front view, Figure (B) is a side view, Figure 3 shows the state in which the assembly of the workpiece with dummy material and the holder is set on the wire saw. Figure (A) is a front view, Figure (B) is a side view, and
The figure shows the state in which the wire has cut into the dummy material under the workpiece to the point where it has completely cut.
B) is a side view, FIG. 5 is a diagram showing the wire row removed from the holder after removing the wafer with a wire saw, FIG. 6 is a front view, FIG. 6 is a side view, and FIG. A front view showing a state in which an assembly of a holder with a split structure and a workpiece with a dummy material is inserted into a wire saw, and FIGS. This is an example of a method for supporting and cutting a workpiece with a holder. Figure 7 shows a concave-convex fitting type holder that supports a workpiece. Figure (A) is a front view, and Figure (B) is a partially cutaway side view. , Figure 8 shows the state in which the workpiece and holder assembly is set on a wire saw, where Figure (A) is a front view and Figure (B) is a front view.
) is a side view, Figure 9 is a diagram showing the state in which the wire has been cut to the holder under the workpiece, Figure (A) is a front view, Figure (B) is
is a side view, FIG. 10 is a front view showing a state in which a holder with a split structure is used as a wire saw, FIG. 11 is a perspective view illustrating the cutting section of a general multi-wire saw, and FIG. Figure (A) is an enlarged perspective view showing the state in which the wire row has been cut to the dummy plate, and Figure (B) is an enlarged side view showing the wafer part. It is a diagram. 1.2.3...Groove roller 4...Wire 5/wire row 6...Work 6-1...Wafer
9...Base 10...Pushing stand
11... Base fixing screw 15. 25... Work holder 18... Dummy material 20... Face plate Applicant Sumitomo Metal Industries Ltd. Figure 1 (A) CB) Figure 2 Figure 3 Figure %4 Figure 5 Figure 6 Figure 8 Figure 9 Teeth Figure 12 (A)

Claims (1)

[Scope of Claims] 1. A processing liquid containing abrasive grains is supplied between a traveling wire and an object to be cut, and a large number of wafers are In a multi-wire saw for cutting the workpiece, the dummy material glued to the object to be cut was supported by a concave-convex fitting type holder and fixed with screws, etc., and the holder was fixed to a table for pushing up the workpiece with screws, etc. A cutting method using a multi-wire saw, characterized in that the dummy material and the holder are cut with the wire, and the dummy material with the wafer attached thereto is removed from the holder. 2. In a multi-wire saw that supplies a machining fluid containing abrasive grains between a traveling wire and an object to be cut, and cuts the object into a large number of wafers by a grinding action while pressing the object against a wire row of a predetermined pitch formed by the wire. , the object to be cut is supported by a concave-convex fitting type holder and fixed with screws, etc., cutting is performed with the holder fixed to a table for pushing up the object to be cut, and further cutting is made to the holder with the wire. A cutting method using a multi-wire saw, which is characterized by removing the wafer from the holder after cutting. 3 In a multi-wire saw that supplies a machining liquid containing abrasive grains between a traveling wire and an object to be cut, and cuts the object into a large number of wafers by a grinding action while pressing the object against a wire row of a predetermined pitch formed by the wire. , a concave-convex fitting type holder that supports a dummy material adhered to the object to be cut, and a screw or bolt for fixing the dummy material screwed to the side surface of the holder, and the holder is adhesively fixed to a table for pushing up the object to be cut. A cutting device using a multi-wire saw, which is characterized by having a structure in which: 4 In a multi-wire saw that supplies a machining fluid containing abrasive grains between a traveling wire and an object to be cut, and cuts the object into a large number of wafers by a grinding action while pressing the object against a wire row of a predetermined pitch formed by the wire. , a structure comprising a concave-convex fitting type holder for supporting the object to be cut, and a face plate for fixing the object to be cut, which is fixed to the holder with screws or bolts, and the holder is adhesively fixed to a table for pushing up the object to be cut. A cutting device using a multi-wire saw.