JPH06114828A - Cutting method with wire saw - Google Patents

Abstract

(57) [Summary] [Purpose] To significantly reduce the number of man-hours required to collect sliced pieces after cutting and to prevent damage after cutting. A method of cutting a plurality of slice pieces while supplying a polishing liquid containing abrasive grains to a cutting portion of an object to be cut 5 while running a wire row 3 stretched in parallel, and after cutting the wire, The wire row 3 is run at least on the side where the row 3 enters the object to be cut 5 while supplying the cleaning liquid W that does not contain abrasive grains and flushes the abrasive liquid, and the wire row 3 and the object to be cut 5 The abrasive liquid in the cutting groove is washed and removed in the process of moving the and relative to each other to extract the wire row 3 from the cutting groove of the object to be cut 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting brittle objects such as semiconductor materials, magnetic materials and ceramics into a large number of thin sliced pieces (wafers) with a wire.

[0002]

2. Description of the Related Art A wire saw is used for cutting a brittle object such as a silicon ingot into thin wafers, and a grooved roller arranged at each vertex of a triangle is multiply threaded at a predetermined pitch. It is an apparatus that presses and cuts an object to be cut (workpiece) while running a wire row and supplying a working liquid containing abrasive grains (hereinafter referred to as an abrasive liquid). Besides, this wire saw is generally used for cutting brittle objects such as semiconductor materials, magnetic materials, and ceramics into thin wafers.

FIG. 1 is a perspective view of a typical wire saw as an example thereof. One wire 1 is wound around three rotatably supported grooved rollers 2A, 2B, 2C in order while being circumscribed. Ring-shaped grooves 2a as shown in FIG. 2 are formed on the outer peripheral surfaces of the three grooved rollers 2A, 2B, 2C, and the wire 1 is wound around these grooves 2a and has a predetermined pitch p. The wire row 3 is formed. This wire row 3 is made to travel (specifically, the wires are made to run), and the work 5 is moved by the lifting table 4.
Are sequentially raised, and the work 5 is cut into slice pieces. At this time, at the same time, from the abrasive liquid supply pipes 6A and 6B, the abrasive liquid containing abrasive grains is supplied to the slit nozzles 7A and 7B which are installed close to each other on the left and right of the work 5, and the slit nozzles 7A and 7B are provided with elongated slit holes at the bottom. The polishing liquid is supplied to the wire row 3. The supplied abrasive liquid is drawn into the cut surface of the work 5 by the traveling of the wire row 3, and the grinding and cutting of the work 5 gradually progresses as the lift table 4 rises. The work 5 is bonded to a dummy plate 8 made of a brittle material, and the dummy plate 8 is a base 9
Is glued to. The base 9 is detachably attached to the lifting table 4 with a tightening screw 10.

3 and 4 show the state at the end of cutting. The wire row 3 is cut into the dummy plate 8 to the middle thereof, and the work 5 is completely cut. Also,
The cutting groove 5b between the slice pieces 5a is filled with the abrasive liquid L containing abrasive grains.

Conventionally, a slice piece 5a after cutting is completed
There were roughly two methods for taking out the food.

In the first method, after cutting, in the wire saw device, the dummy plate 8 is sequentially cut from the slice piece 5a on the front side of the work 5 while the wire row 3 is still cut to the dummy plate 8. It is a method of collecting in the device, so to speak, breaking off at the final cut portion of 8.

In this method, since the slice pieces have a high suction force due to the abrasive liquid L in the cutting groove 5b, there is a high risk that the slice pieces 5a will crack when the thin slice pieces 5a are taken out. It was

In contrast to this method, a method of applying a cleaning liquid to the work 5 to wash away the abrasive liquid in the cutting groove 5b was also considered. That is, it is intended to prevent the slice piece 5a from being damaged by weakening the suction force of the abrasive liquid by the cleaning liquid, but the width of the cutting groove is very narrow at most 0.2 to 0.3 mm, and the cleaning liquid is difficult to enter. It was confirmed that a large effect cannot be obtained even when applied to the thin slice piece 5a.

The second method is to move the work 5 in a direction for pulling out the work 5 from the wire row 3 (in the example of FIG. 1, lower the elevating table 4) while the wire row 3 is running, and to move the work piece 5 to the base 9.
This is a so-called outside-device sampling method in which the workpiece 5 is removed and the slice piece 5a is collected outside the device.

According to this outside-device sampling method, the wire array 3
Passes through the cutting groove 5b again, so that the slice pieces 5a, 5
It is intended to facilitate the collection of slice pieces by weakening the suction force between a.

There are the following three methods for collecting the sliced pieces 5a outside the machine in the second method. (1) Similar to the first method, it is a method in which the slice pieces 5a on the front side of the work 5 are sequentially cut off at the final cut portion of the dummy plate 8.

However, even if the suction force between the slice pieces 5a, 5a due to the abrasive liquid is weaker than the in-apparatus sampling method, the suction force does not become zero due to the residual abrasive liquid, and there is a risk of damage to the slice pieces 5a. The nature is high.

(2) A method of heating the base 9 and the dummy plate 8 to reduce the adhesive strength of the adhesive, peeling the work 5 from the dummy plate 8, and then separating the slice pieces 5a from each other. . However, it is impossible to completely prevent the trouble of breakage when the sliced pieces 5a are separated by the residual abrasive liquid.

(3) A method of immersing the work 5 together with the base 9 in a solvent to dissolve and remove the adhesive. However, even with this method, it is difficult to completely remove the residual abrasive liquid from the narrow cutting groove, and it is not possible to reliably prevent the trouble of breakage when separating the slice pieces 5a.

For this kind of problem, several improvements have been proposed. For example, Japanese Patent Laid-Open No. 1-2167
In Japanese Patent Laid-Open No. 59-164164, there is a method in which the cut work is dipped in washing oil and the wire row is pulled out while performing ultrasonic cleaning.
Methods have been proposed for removing the wire rows after washing with washing oil at 30 ° C. or higher.

[0016]

As described above, generally, the width of the groove formed by cutting the wire saw is at most 0.2 to 0.3 m.
It is very narrow with m. Even if ultrasonic cleaning as a conventional technique is applied there, since the width of the cutting groove is narrow, the vibration of the cleaning liquid is difficult to be transmitted to the abrasive grains, and the time required for cleaning increases as the surface area of the sliced piece increases. there were. Also, in the method using oil washing,
It takes time to wash out the abrasive liquid filling the cutting grooves, and it is difficult to apply it when the area of the wafer is large.

Therefore, a main object of the present invention is to efficiently remove the polishing liquid from the cutting groove of the work after cutting and surely prevent damage loss when collecting sliced pieces.

[0018]

Means for Solving the Problems The above-mentioned problems are solved in a method of cutting a plurality of slice pieces while running a row of wires arranged in parallel and supplying an abrasive containing abrasive grains to a cutting portion of an object to be cut. After cutting, the wire row is run while supplying a cleaning liquid that does not contain abrasive grains to the wire row on which the wire row enters at least the object to be cut and that flushes the abrasive liquid, and the wire row and the object to be cut. This can be solved by relatively moving and to extract the wire row from the cutting groove of the object to be cut.

[0019]

The operation of the present invention will be specifically described with reference to FIG.
FIG. 6 is a view showing a state in which the wire row 3 is being extracted from the work 5 by lowering the elevating table 4 after the cutting is completed by the wire saw. As shown in FIG. 5, the running wire 1 is sprayed with the cleaning liquid W before entering the work 5 (on the entrance side). The selection of the cleaning liquid depends on the liquid used for the polishing liquid. If it is oil-based, the washing liquid is preferably washing oil such as kerosene or an organic solvent. As long as it has a low viscosity, it may be the same as the oil itself used in the polishing liquid or water. The cleaning liquid W applied to the wire row 3 is dragged by the wire 1 and enters the cutting groove 5b in the work 5, and the abrasive liquid is washed out from the cutting groove 5b by the movement of the wire 1. During this process, the work 5 is slowly descending, so that the cutting groove 5
The cleaning liquid W is spread all over the inside of b, and all the abrasive liquid L is discharged from the cutting groove 5b.

As a result, at the time of separating the sliced piece inside or outside the apparatus, there is no fear of damage due to the suction force of the residual abrasive liquid. Since the width of the cutting groove 5b is larger than the diameter of the wire 1 and the cleaning liquid W flows around the traveling wire 1, the wire 1 does not come into direct contact with the surface of the slice piece 5a and the slice piece 5a is cut. There is no saw mark on the surface.

[0021]

EXAMPLE FIG. 5 shows an example of an apparatus for carrying out the method of the present invention. The device example of FIG. 5 is basically the same as the device shown in FIGS. 1 and 2, and the same portions are denoted by the same reference numerals and detailed description thereof will be omitted. In the present apparatus example, the cleaning liquid supply pipe 10 is provided adjacent to the abrasive liquid supply pipes 6A and 6B.
A and 10B are provided. FIG. 5 shows a state before the work 5 is completely cut and the elevating table 4 is lowered. The polishing liquid supply from the polishing liquid supply pipes 6A and 6B that has been performed during the cutting is stopped, and instead, the cleaning liquid W is supplied from the cleaning liquid supply pipes 10A and 10B to the slit nozzles 7A and 7B. At this time, by using a switching bubble or the like, the abrasive liquid supply pipes 6A, 6A
The cleaning liquid W may be passed through B. The cleaning liquid W is supplied in the form of a water film that intersects the entire wire row 3 through the elongated slit holes of the slit nozzles 7A and 7B in the direction penetrating the paper surface of FIG. Be brought in. Then, when the wire row 5 starts traveling, the elevating table 4 is sequentially lowered.

After the wire row 3 has been extracted from the work 5, the base 9 and the lift table 4 can be removed and the slice pieces 5a can be sequentially sampled from the outside. At this time, as described above, since the abrasive liquid does not remain in the cutting groove 5b, no damage occurs when the slice piece 5a is sampled.

If the cutting groove 5b is completely cleaned,
It is also possible to omit finishing washing after collecting the slice pieces 5a. Moreover, in the method of the present invention, since the abrasive liquid in the cutting groove 5b has already been removed, even if ultrasonic cleaning is performed after cutting, the time required for it is extremely short.

Further, by supplying the cleaning liquid W to the wire 1, the groove 2a of the grooved roller can be cleaned. The cleaning of the groove 5a means that, for example, when the wire is replaced and wound again on the grooved roller, the wire 1 is closely attached to the bottom of the groove 2a to form the wire row 3 having an accurate pitch. No cleaning operation is required.

When the wire row 3 travels in one direction, for example, in the direction indicated by the arrow A, the cleaning liquid flowing down from the slit nozzle 7a located on the inlet side of the work 5 flows into the grooved roller 2.
The roller grooves are cleaned in the order of c, 2a and 2b, and similarly, the cleaning liquid flowing down from the work 5 from the slit nozzle 7b on the outlet side also cleans the roller grooves of the grooved rollers 2c, 2a and 2b. Of course, if the cleaning of the grooved roller is not necessary, it is not necessary to let the cleaning liquid flow down from the slit nozzle 7b. When the wire row 3 travels back and forth, the slit nozzles 7A, 7A
The cleaning liquid flowing down from B is cut groove 5b and grooved roller 2
The cleaning of the roller groove is alternately performed.

The cleaning liquid W may be supplied only from the slit nozzle 7A.

The effects of the present invention will be described below with reference to examples of the present invention. (Example 1) A work was cut with a wire saw having the same shape as that shown in FIG. A piano wire having a diameter of 0.16 mm was stretched at a pitch of 0.7 mm as a wire row of the wire saw. A quartz ingot having a cross-sectional size of 125 mm × 125 mm and a length of 200 mm was used for the work. The lower side of the work is glued to the glass dummy plate, and the lower side of the dummy plate is
I glued it to the base. The base is fixed to the lifting table by tightening screws.

This wire row was run in one direction at a speed of 400 m / min, and a grinding liquid in which GC # 600 abrasive grains were mixed with lapping oil was made to flow down from the slit nozzle onto the wire row, and 0.4 mm / min was applied. The work was pushed up at a speed and cut into 278 slice pieces having a thickness of 0.45 mm. After cutting, while moving kerosene as a cleaning liquid from the slit nozzle instead of the abrasive liquid, the wire row is run at 400 m / min in one direction, and the lifting platform is lowered at a speed of 5 mm / min to pull out the wire row from the work. It was After that, the work is removed from the lift together with the base, the base and the glass dummy plate are heated on the hot plate to soften the adhesive, and 50 to 70 slice pieces are collectively peeled off from the dummy plate. It was immersed in kerosene, separated into slices, and washed. The time required to process all slice pieces was 2 hours after the completion of cutting, and there was no breakage of the slice pieces.

On the other hand, after cutting, the work is pulled out from the wire row under the same conditions while flowing the polishing liquid from the slit nozzle without flowing down the cleaning liquid, and the slice pieces are peeled off from the dummy plate by the same method to make kerosene. Dip and slice 1
Separate cleaning was performed for each sheet.

In this case, the processing of all slice pieces required 5 hours after the completion of cutting, and the breakage rate of the slice pieces was 6%.

It took 1 hour to clean the grooved roller for wire replacement, but in the case of the method of the present invention,
No cleaning of the grooved roller was necessary.

(Example 2) A work was cut with the same shape as the wire saw shown in FIG. A piano wire having a diameter of 0.16 mm was stretched at a pitch of 0.55 mm as a wire row of the wire saw.

The workpiece has a cross-sectional size of 100 mm × 100.
A polycrystalline silicon ingot having a length of mm and a length of 220 mm was used. The work is adhered to the glass dummy plate on the lower side,
The lower side of the dummy plate was bonded to the base. The base was fixed to the lift with the tightening screw.

This wire row was run in one direction at a speed of 400 m / min, and a grinding liquid containing GC # 1000 abrasive grains mixed with a water-soluble polishing agent was made to flow down from the slit nozzle onto the wire row.
The work is pushed up at a speed of 0.5 mm per minute to obtain a thickness of 0.
The work was cut into 390 35 mm slices. After cutting, run the wire row at 400 m / min in one direction while flowing water as the cleaning fluid from the slit nozzle instead of the abrasive fluid, and lower the elevator table at a speed of 5 mm / min to remove the wire row from the work. It was After that, the work together with the base is removed from the lift, immersed in kerosene in the ultrasonic cleaning tank, ultrasonically cleaned for 10 minutes, and then the base and the glass dummy plate are heated on the hot plate to soften the adhesive. Then, 70 to 100 slice pieces were collected and peeled off from the dummy plate. The abrasive grains were completely removed from one side of the slice, and each slice piece could be easily peeled off. Further, finishing washing was not necessary at all, and the slice pieces were not damaged at all.

On the other hand, after cutting, the work was taken out from the wire row under the same conditions while the abrasive was allowed to flow down from the slit nozzle while the cleaning liquid was not allowed to flow down, and the work was immersed in water for ultrasonic cleaning for 3 hours. Abrasive grains remain in the area close to the dummy plate, and the area ratio of the slice pieces from which the abrasive grains have been removed is about 7
It was 0%. Then, heat the base and the dummy plate on the hot plate to soften the adhesive, collect 70 to 100 slice pieces together, peel off the dummy plate, and soak in water to separate the slice pieces one by one. Washed. The processing time for all slices required 6 hours after heating, and the damage rate of slices was 11% despite careful handling.
Met.

[0036]

As is apparent from the above description, when a brittle object such as a semiconductor material, a magnetic material, or a ceramics is cut into a large number of thin slice pieces by a wire string stretched in parallel, the method of the present invention is used. In this case, the number of man-hours for collecting sliced pieces can be significantly reduced, and the sliced pieces can be reliably prevented from being damaged.

[Brief description of drawings]

FIG. 1 is a perspective view of a wire saw conventionally used.

FIG. 2 is an enlarged view of a main part of a grooved roller in the wire saw shown in FIG.

FIG. 3 is a perspective view showing a state immediately after being cut with a wire saw.

FIG. 4 is an enlarged side view of a work immediately after being cut with a wire saw.

FIG. 5 is a front view of a wire saw according to an example of the present invention.

FIG. 6 is a side view showing a process of extracting a wire row from a work by the method of the present invention.

[Explanation of symbols]

1 ... Wire, 2 ... Grooved roller, 3 ... Wire row, 5 ... Work piece, 5a ... Slice piece, 5b ... Cutting groove, 6 ... Abrasive liquid supply pipe, 7 ... Slit nozzle, 8 ... Dummy plate, 9 ... Elevating table ,
L ... Abrasive liquid, W ... Cleaning liquid.

Claims (1)

[Claims] 1. A plurality of slices are provided by feeding an abrasive liquid containing abrasive grains to a cutting portion of an object to be cut when cutting the object while the wires are stretched in parallel and pressed against the wire to be cut. In the method of cutting into pieces, after the completion of cutting, the wire row is run while supplying a cleaning liquid that does not contain abrasive particles and does not contain abrasive grains in the wire row on which the wire row at least enters the object to be cut, A method for cutting with a wire saw, comprising extracting a wire row from a cutting groove of an object to be cut.