JPH07314436A - Wire saw device - Google Patents

Abstract

PURPOSE:To enhance a sliced wafer in slicing speed and parallelism between both top and rear surfaces thereof and easily extract a wire from a cutting groove of a sliced work by a method wherein the wire is obliquely run, and a work is pressed against the oblique part of the running wire with the supply of cutting liquid to be cut. CONSTITUTION:A wire 2 is obliquely run, and a work 45a is pressed against the oblique part of the running wire 2 to be sliced with the supply of cutting liquid containing abrasive grains. At the start of cutting, the wire 2 comes into contact with a corner of the rectangular work 45a with a remarkably short contact length. Therefore, a cutting resistance is very small, and the wire 2 is remarkably easily cut into the corner of the work 45a at a predetermined interval. The cutting liquid is supplied into the center of the work 45a deep in the cutting groove of the work 45a together with the wire 2 running in a slant direction. Cut powder of the work 45a smoothly flows out of the cutting groove of the work 45a together with the cutting liquid. Since the cut powder never stagnates in the cutting groove, the wire 2 can be easily extracted therefrom.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel wire saw device for slicing a workpiece, for example, a prismatic ingot, to form a wafer for semiconductor integrated circuits, solar cells and the like.

[0002]

2. Description of the Related Art A wafer is obtained by cutting a silicon single crystal into thin slices and grinding the surface. Single crystal silicon wafers are widely used in various applications, for example, as a raw material for solar cells and as a raw material for various integrated circuits. The diameter of the single crystal silicon wafer is gradually increasing with the improvement of the single crystal pulling technique.

In a conventional ingot slice, a wire (62) is run as shown in FIG. 6, and the ingot (66) is run while supplying a cutting fluid (67) containing abrasive grains.
A general method is to press and slice. In this method, a wire (62) is suspended at regular intervals on a processing head roller (61) provided corresponding to each vertex of a triangle, and a lifting device (63) such as a cylinder provided below the wire (62). ), The ingot (66) is pressed against the horizontal running portion of the wire (62) from below, and the cutting fluid (67) is discharged from the cutting fluid supply section (65) to ingot (66). ) Is supplied to the kerf (64) and is cut.

Cutting fluid supply unit (65) along with running of wire (62)
The ingot (66) is gradually cut by the cutting fluid (67) containing abrasive grains supplied from. Ingot (6
When 6) is completely cut from the upper end to the lower end, lower the lifting device (63) and insert the wire (6) from the notch (64) of the ingot (66).
2) is detached and the ingot (64) is taken out, but when pushing the ingot (66) from below the wire (62), the width of the wire (62) stretched over the ingot (66). The cutting powder is filled in the numerous kerfs (64) formed by the solidification process, and even if the lifting device (63) is pulled down, the resistance from the kerf (64) of the ingot (66) causes the wire (62) cannot be removed. If you try to force the wire (62) out of the kerf (64), the sliced ingot (66)
In some cases, the wafer may be damaged, and the push-up method from the bottom up causes the wire
Cut (62) and insert wire (6) through the notch (64) in the ingot (66).
I try to pull out 2).

When the wire (62) is cut, the next ingot (6
The wire (62) must be rewound around the processing head roller (61) during the cutting operation of 6), but this wire winding operation is a time-consuming operation.
After cutting the wire (62) every time the (66) is cut, pulling out the wire (62) from the groove (64) of the ingot (66) and removing the ingot (66) from the lifting device (63). However, if the work of winding the new wire (62) around the processing head roller (61) again is repeated, there is a problem that the workability of ingot cutting is significantly reduced.

In addition, in the ingot push-up cutting method, the cutting fluid (67) easily collects at the bottom of the kerf (64), which means that cutting powder also easily collects at the bottom. The cutting powder adheres to the abrasive grains and kills the sharpness, which reduces the cutting speed and tends to be supplied with new cutting fluid.
The width of the groove becomes wider, and the width of the kerf (64) where cutting powder tends to accumulate tends to be narrower in the central part of the kerf, and the cut wafer tends to have a biconvex lens shape. There was also the problem of being bad.

[0007] An even bigger problem is the ingot (66).
If the shape is prismatic, the wire (62) will come into contact with the entire length of the upper surface of the ingot (66) at the start of cutting, and the wire (2) will not be bite at the start of cutting and the wire (2) will fly. was there.

[0008]

The problems to be solved by the present invention are as follows.
A cutting fluid containing abrasive grains is supplied together with the wire to the center of the kerf of the work piece, effectively cutting the work piece and promptly discharging from the kerf after cutting the work piece. , Improve the cutting speed of both front and back surfaces of the cut wafer, increase the parallelism of both front and back surfaces, make it easier to pull out the wire from the cut groove of the cut workpiece, cut the prismatic workpiece In this case, the wire should not fly at the start of cutting.

[0009]

A wire saw device (A) according to claim 1 runs a wire (2) in a tilting direction, and a workpiece (45a) is run at a tilted running portion of the wire (2). Move the cutting part (1) and the attached prismatic work piece (45a) toward the inclined traveling part of the wire (2), and move the work piece (45a) from the corner of the work piece (45a). The moving device (30) that cuts the wire (2) at the inclined traveling part of the wire (2) and the cutting fluid (3
It is characterized in that it is configured with a cutting fluid supply part (35) for supplying 5a).

According to this, the wire (2) is caused to travel while being inclined, and the workpiece (45a) is pressed against the inclined portion of the traveling wire (2) while supplying the cutting fluid (35a) containing abrasive grains. The wire (2) contacts the corner of the prismatic work piece (45a) at the beginning of cutting, and the contact length is extremely short.Therefore, the cutting resistance is very small. The wires (2) bite into the corners of the prismatic work piece (45a) at predetermined intervals very easily. After that, the wire (2) does not fly at the start of cutting because it is cut along the biting part.

The supply of the cutting fluid (35a) is started immediately before or at the same time as the start of cutting. The cutting fluid (35a) is supplied along with the wire (2) traveling in an oblique direction to the kerf () of the workpiece (45a). 45 b)
Deep into the center of the workpiece (45a),
The work piece (45a) is cut. The cutting powder of the work piece (45a) cut by the abrasive grains in the cutting fluid (35a) flows out smoothly from the kerf (45a) of the work piece (45a) together with the cutting fluid (35a). (Four
5 a) It does not accumulate inside. Therefore, after cutting the work piece (45a) from one side surface to the other side surface, the work piece moving device (30) is operated to pull out the work piece (45a) in the horizontal direction. Since the amount of cutting powder remaining in the groove (64) is small, it does not become a resistance when the wire (2) is taken out, and the wire (2) can be easily detached from the cutting groove (64).

In addition, the cutting fluid (35a) supplied to the kerf (45a) of the work piece (45a) is sufficiently moved to the central portion of the work piece (45a) as the wire (2) runs in the vertical direction. To be supplied to
The cutting amount of the cutting groove (64) in the inside is not so much reduced as compared with the peripheral portion, and the parallelism between the front and back surfaces of the cut wafer is improved as compared with the conventional example.

The traveling direction of the wire (2) can be adjusted by traveling from diagonally above to diagonally downward, conversely traveling diagonally from below to diagonally above, and by reciprocating and making a difference in the feed amount. In some cases, the workpiece (45a) may be gradually fed out in the same direction as shown in FIGS.
There are cases where cutting is performed from the upper corner of a) and where cutting is performed from the lower corner.

When traveling diagonally from the upper side to the lower side, it is only necessary to supply the cutting fluid (35a) to the workpiece (45a) from above.
As the (2) runs, the cutting fluid (3
5a) arrives, but when running vertically from diagonally below to diagonally above, the wire (2) runs against the downward direction of the cutting fluid (35a), so the cutting groove (45a) of the cutting fluid (35a) runs. The retention time of the cutting fluid (35a) in the vicinity of the wire (2) in () becomes long and the cutting is effectively performed. Most of the cutting powder generated by cutting is cutting fluid.
(35a) and the wire (2) are separated from the running part, and the groove (45
It will flow down from b) and the cutting performance of the abrasive grains will not be impaired.

Here, in the case of FIG. 5, since the kerf (45 a) is formed obliquely downward, the cutting fluid containing a large amount of cutting powder.
Compared with the case shown in Fig. 6 (the groove (35a) is formed so as to face obliquely upward), (35a) is more likely to flow out, and by combining it with the traveling direction of the wire (2). Each has a characteristic cutting capability.

[0016]

The present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows the winding state of the wire (2) of the cutting portion (1) and its drive system in the first embodiment. In the present embodiment, the object to be processed (45a) is like a single crystal ingot, and its shape is substantially prismatic.

The wire (2) is wound around a pair of reels (3) and (4) in an aligned state, and a pair of spring (or weighted) dancer rollers (5) (6) and tension rollers are provided between them.
(7) Through (8), the processing head roller with three guide grooves provided at the apex position of the triangle when viewed from the front (10) (11) (1
It is wound multiple times on 2). Processing head roller (1
The configuration of the first embodiment of (0), (11) and (12) is as shown in FIG. In the case of the structure in which the processing head roller (10) is provided, as shown in FIG. 6, in the opposite case, that is, one processing head roller (10) is provided in the middle lower part of the upper pair of processing head rollers (11) (12). In the case of the structure provided, as shown in FIG. 4, the structure in which the two are rotated by 90 °, that is, one processing head on the intermediate side of the pair of upper and lower processing head rollers (11, 12) In some cases, the structure is such that a roller (10) is provided. Here, in the cutting portion (1), a portion where the wire (2) travels obliquely serves as a cutting place of the workpiece (45a).

The workpiece (45a) is attached to the workpiece mount (29) of the workpiece moving device (30) for moving the workpiece mount (29) in the horizontal direction. The work piece (45a) is in contact with the cutting position of the wire (2) with a predetermined force through the abrasive grains contained in (35a), and the work piece (45a) is cut by the relative movement of both. It is designed to be followed.

The supply-side reel (3) is connected to the supply-side torque motor (1
4) is driven while slightly resisting the wire (2) in the feeding direction, and the winding reel (4) is driven in the winding direction by the winding torque motor (15). To be done. Incidentally, a traverse mechanism (not shown) is attached to these reels (3) and (4), and as a result of this action, the wire (2) is always in an aligned winding state, and the reel (3)
It is wrapped around the outer circumference of (4) or unwound.

On the other hand, the pair of tension rollers (7) and (8) are
It is designed to be driven by a drive motor (9).
That is, the rotation of the drive motor (9) is transmitted through the intermediate shaft (16) and the pair of gears (17) and (18) as one rotation transmission path to the input shaft of the first differential gear mechanism (21) ( 19) and further transmitted to one tension roller (7) via the output shaft (20).

As the other rotation transmission path, the timing belt (23) branches in the middle and the transmission is transmitted to the other tension roller (8) through the intermediate shaft (24). Further, the rotation of the intermediate shaft (16) is passed through the timing belt (25),
It is transmitted to the input shaft (26) of the second differential gear mechanism (22),
Differential gear mechanism (22) output shaft (27) and timing belt
It is transmitted to the drive shaft of each processing head roller (10), (11) and (12) via (28). The first differential gear mechanism (21) and the second differential gear mechanism (22) both have control shafts (31) and (32) as a third shaft, and the reversible parts are respectively provided at those parts. It is connected to a rotatable tension control motor (33) and a phase control motor (34).

The feature of the first embodiment of the present invention shown in FIG. 1 is that the portion of the wire (2) for cutting the workpiece (45a) runs obliquely as described above. That is the point. The wire (2) may be run diagonally from top to bottom as indicated by solid lines in FIGS. 5 and 6, or conversely, from bottom to top as indicated by broken lines. Or it may be reciprocated.
When reciprocating, the cutting conditions of the pair of left and right diagonally running parts are the same, so the work piece (4
5a) can be cut. In the first embodiment, a case where the wire (2) is run from diagonally above to diagonally below and the rectangular workpiece (45a) is cut from the lower corner as shown in FIG. 5 will be described as an example.

Reference numeral (40) is an intermittent rotation device installed on the side of the cutting part (1), which is provided around the rotating column (43) and which moves the workpiece (3).
(0) are projected radially at 90 ° intervals, and the rotating cylinder (43)
It is designed to rotate at an angle of 90 °. The intermittent rotation mechanism of the intermittent rotation device (40) has a known structure, and a drive mechanism using a barrel cam, for example, can be considered. A horizontal arm (32) is attached to the tip of the workpiece moving device (30) so as to project horizontally from the tip and to be retracted into the tip, and a base ( 42)
Is installed.

The workpiece (45a) is fixed to the workpiece mount (29) mounted on the base (42) with an adhesive, and the base (4a)
The dovetail groove (42) of 2) is inserted into the dovetail groove of the workpiece mount (29) to mount the workpiece mount (29) on the base (42). The base (42) and the workpiece mounting base (29) are fixed by pressing the dovetail ridges (42a) against the dovetail groove by, for example, a cylinder (not shown).

FIG. 2 is a schematic front sectional view of FIG. 1, showing a cutting portion (1).
Is housed in the wire saw body device (a), and the intermittent rotation device (40) is installed adjacent to the cutting part (1). A preliminary cleaning device (b) and a main cleaning device (c) are installed at the stop positions of the respective workpiece moving devices (30) of the intermittent rotation device (40). The preliminary cleaning device (b) and the main cleaning device (c) have basically the same structure. According to Fig. 2, the preliminary cleaning device (b)
This cleaning device (c) includes a cleaning liquid storage tank (46) that stores the cleaning liquid (41), a pump (38) and a filter (39) connected to the cleaning liquid storage tank (46), and a workpiece ( 45b) cleaning solution
It is composed of a shower nozzle (36) and (37) for showering (41), and these are a preliminary cleaning device (b) and a main cleaning device (c).
It is stored in the hanger. The preliminary cleaning device (b) and the main cleaning device (c) are independent of each other and can be moved.

Next, the operation of the present invention will be described. In Fig. 3, the base is installed in the attachment / detachment zone (D) of the intermittent rotation device (40).
Remove the work piece mount (29) with the work piece (45b) (= washed cutting ingot) attached to (42) from the base (42), and then cut the work piece (45a) (= before cutting) The work piece mounting base (29) equipped with the ingot (1) is mounted on the base (42). When the intermittent rotation device (40) is activated in this state and rotated 90 °, the work piece (45a) mounted in the attachment / detachment zone (D) is removed from the attachment / detachment zone (D).
Rotate 90 ° from (D) to the position of the cutting zone (A) and stop.

During this time, the drive motor (9) is operating,
The wire (2) travels around the processing head rollers (10), (11) and (12). By operating the work piece moving device (30) which coincides with the cutting zone (A), the work piece (45a) is traveling diagonally from the processing head roller (11) to the wire (12) ( Press the corner of the square workpiece (45a) against 2), and at the same time, at the contact part between the workpiece (45a) and the wire (2), supply the cutting fluid (35).
The cutting fluid (35a) is supplied from the cutting fluid (35a), and the workpiece (45a) is cut by the abrasive grains contained in the cutting fluid (35a).

At the start of cutting, the contact length between the wire (2) and the corner of the rectangular work piece (45a) is very small, so the wire (2) is easily cut into the corner at a predetermined interval. There is no such thing as going in and the wire (2) flying.

As the cutting progresses, as shown in FIG. 5, the cutting fluid (35a) is supplied to the inside of the cut groove (45a) along the wire (2) and the workpiece (45a). To cut off effectively. The cutting powder generated by the cutting flows downward along the running groove (45a) of the workpiece (45a) because the cutting groove (45a) is diagonally downward, Promptly cut (4
Go out of 5a).

Since the abrasive grains in the cutting fluid (35a) are transmitted to the wire (2) and enter the inside of the cut groove (45a) as described above, the change in the cutting speed between the peripheral portion and the inside is small. Therefore, the parallelism between the front and back surfaces of the cut wafer is remarkably improved as compared with the conventional one.

The work piece (45a) is cut in this manner. In this case, the square work piece (45a) is obliquely cut.
Since a) is cut, it is necessary to increase the thickness of the work piece mounting base (29). When the cutting of the work piece (45a) is completed, the work piece moving device (30) is operated in the retracting direction to pull out the work piece (35b) from the wire (2). In this case, the cutting powder flowed down from the kerf (45a) and was not accumulated much in the kerf (45a), so the wire (2) smoothly moved from the kerf (45a).
Can be pulled out. The processed object (45b) is in a muddy state covered with the cutting fluid (35a) containing a large amount of cutting powder.

When the cutting work is completed, the intermittent rotation device (40)
Is operated to transfer the cut-completed workpiece (45b) from the position of the cutting zone (A) to the position of the preliminary cleaning zone (B) by 90 °. A pre-cleaning device (b) is installed here, and the pumping pump (38) is activated by sensing that the processed workpiece (45b) has been transferred into the pre-cleaning device (b), The shower nozzle
It is sprayed from (36) onto the processed workpiece (35b), and the mud-like cutting fluid containing cutting powder and abrasive grains is roughly washed off.

The workpiece (45a) newly transferred from the attachment / detachment zone (D) is cut by the same operation as described above. When this workpiece (45a) is cut at the position of the cutting zone (A), the intermittent rotation device (40) is operated to rotate it further by 90 °. As a result, the workpiece (45b) preliminarily cleaned in the preliminary cleaning zone (B) is transferred to the main cleaning zone (C),
The workpiece (45b) cut in the subsequent cutting zone (A) is transferred to the preliminary cleaning device (B).

The prewashed workpiece (45b) transferred to the main washing zone (C) has a clean washing liquid as a shower nozzle.
It will be sprayed from (37) and cleanly washed.
In this way, the cleaned and processed workpiece (45b) that has been main-cleaned in the main cleaning liquid zone (E) waits for the completion of cutting of the workpiece (45a) newly supplied to the cutting zone (A), and then intermittently Rotating device (40)
By 90 °, and moves from the main cleaning zone (C) to the attachment / detachment zone (D). Work piece mount with work piece (45b) that has been cleaned by the worker when moved to the attachment / detachment zone (D)
(29) is removed from the base (42), the workpiece mount (29) with the workpiece (45a) before machining is attached to the base (42), and the next cutting start preparation is made. . In this way the intermittent rotation device (40)
By rotating the 360 °
Pre-cleaning → main cleaning → removal of the work piece "is automatically performed, and the work piece (45b) that has been beautifully cleaned and completely cleaned in the attachment / detachment zone (D) can be obtained. It can be kept at.

Further, only one work piece (45a) to be cut may be mounted on the work piece mounting base (29) as shown in FIG. It is possible to install two or more.

Next, description will be made on a case where the wire (2) travels from diagonally downward to diagonally upward as shown by the broken line in FIG. In this case, the cutting fluid supply part (35) is the work piece (45a)
It may be installed above, or below or sideways, and it is desirable that the cutting fluid (35a) is effectively poured into the cutting portion. The cutting fluid (35a) containing abrasive grains supplied to the cutting fluid supply section (35) is supplied to the cutting part of the workpiece (45a), and the wire (2) is moved along with the diagonal movement of the wire (2). ) And will be drawn into the cut groove (45 a).

The running direction of the wire (2) may be one direction from diagonally above to diagonally below (or diagonally below to diagonally above), or it may be intermittently moved while gradually changing its traveling direction. You may do it.

Further, as shown in FIG. 6, a rectangular work piece (45a)
You may make it cut | disconnect by the wire (2) from the lower corner part. In this case, unlike the case of FIG. 5, the cutting groove (45) is directed obliquely upward, and the outflow rate of the cutting fluid (35) is slowed down.

[0039]

As described above, according to the present invention, the wire is run in the tilt direction, and the workpiece is cut at the tilt running portion of the wire while supplying the cutting fluid. Since the contact length is extremely short because it contacts with the wire, the cutting resistance is very small and the wire bites into the corner of the prismatic work piece at a predetermined interval very easily,
After that, it will be cut along the bite part, so the wire will not fly at the start of cutting.
Further, as described above, the wire is slanted to travel, and while the cutting fluid containing abrasive grains is supplied, the workpiece is pressed against the slanted traveling portion of the traveling wire to be sliced, so the cutting fluid is slanted in an oblique direction. It penetrates into the central part of the kerf of the work piece together with the wire that travels. The cutting powder generated by cutting the abrasive grains in the cutting fluid smoothly flows out from the kerf of the workpiece together with the cutting fluid, and does not collect in the kerf. Therefore, a small amount of cutting powder remains in the kerf, which does not serve as resistance when the wire is taken out, and the wire (2) can be easily separated from the kerf. In addition to this, since the cutting fluid is sufficiently supplied to the central part of the kerf of the work piece as described above, the cutting amount of the kerf in the inside did not decrease so much as compared with the peripheral part and was cut out. There is an advantage that the parallelism between the front and back surfaces of the wafer is improved as compared with the conventional example.

[Brief description of drawings]

FIG. 1 is a perspective view showing an internal mechanical structure of an embodiment of a wire saw device used in the present invention.

FIG. 2 is a front sectional view showing a schematic configuration of the wire saw device of FIG.

FIG. 3 is a plan view showing a schematic configuration of the wire saw device of FIG.

FIG. 4 is a front sectional view showing a schematic configuration of another wire saw device of the present invention.

FIG. 5 is a cross-sectional view of a main part when a wire is run diagonally from top to bottom in the present invention and is cut from the lower corner of a rectangular workpiece.

FIG. 6 is a cross-sectional view of a main part when a wire is run diagonally from top to bottom in the present invention and is cut from the upper corner of a square work piece.

FIG. 7 is a sectional view of a main part of a conventional example.

[Explanation of symbols]

 (1)… Cutting part (2)… Wire (30)… Moving device (35 a)… Cutting fluid (35a)… Cutting fluid (45a)… Workpiece

Claims (3)

[Claims] 1. A wire is run in an inclined direction,
A cutting part that makes the workpiece in the inclined traveling part of the wire,
A moving device that moves the mounted prismatic workpiece toward the inclined traveling portion of the wire and cuts the workpiece from the corner of the workpiece at the inclined traveling portion of the wire; A wire saw device comprising a cutting fluid supply section for supplying cutting fluid to the cutting section. 2. The running direction of the wire is configured so as to be directed obliquely from above to below, and the cutting fluid supply section supplies the cutting fluid from above the workpiece to the cutting section of the workpiece by the wire. Claim 1 characterized by the above-mentioned.
Wire saw device described in 3. The running direction of the wire is configured so as to be directed obliquely downward to upward, and the cutting fluid supply unit supplies the cutting fluid laterally or downwardly to the cutting portion of the workpiece by the wire. Claim 1 characterized in that
The wire saw device according to.