TWI861261B - How to restart the operation of the wire saw - Google Patents

Abstract

The present invention provides a method for restarting the operation of a wire saw. When restarting the cutting of a workpiece that is broken in the middle due to an abnormality such as a wire break, the wire breakage will not occur due to the wire pulling the workpiece. The present invention is a method for restarting the operation of a wire saw, wherein a fixed abrasive saw wire with abrasive fixed on its surface is hung on a multi-groove drum to form a saw wire array, the fixed abrasive saw wire is moved back and forth along an axial direction, and a workpiece is relatively pushed against the saw wire array to feed, and the workpiece is cut into a wafer shape. During the operation of the wire saw, when the cutting of the workpiece is interrupted halfway through the workpiece, the method restarts the cutting of the workpiece. The method is characterized in that the fixed abrasive saw wire, which has worn away the abrasive, is arranged at the feed position of the workpiece where the cutting of the workpiece is interrupted, and the cutting of the workpiece is restarted.

Description

How to restart the operation of the wire saw

The present invention relates to cutting of workpieces by wire sawing, and more particularly to a method for restarting the operation of the wire saw when cutting is interrupted.

Conventionally, a wire saw is known as a means for cutting wafers from a silicon wafer or a compound semiconductor wafer. In such a wire saw, for example, a free abrasive type, a plurality of saw wires are wound around a plurality of drums to form a saw wire array, and the saw wires are driven at high speed in an axial direction, and a cutting fluid is appropriately supplied and a workpiece is fed by the saw wire array, so that the workpiece is cut at the position of each saw wire, thereby cutting a plurality of wafers at the same time (Patent Document 1).

Here, an example of a general wire saw is shown in Fig. 2. As shown in Fig. 2, this wire saw 201 is mainly composed of the following: a saw wire 202 (high-tension steel wire) for cutting a workpiece W; a grooved drum 103 around which the saw wire 202 is wound; a tension adjustment mechanism 104 for adjusting the tension of the saw wire 202; a mechanism 105 for feeding the workpiece W to be cut downward; and a mechanism 206 for supplying cutting fluid during cutting.

The saw wire 202 is unwound from the saw wire reel 107 on one side, passes through a traverser 108, a pulley 109, and a tension adjustment mechanism 104, is wound around the grooved drum 103 about 300 to 500 times, and is then taken up by the saw wire reel 107' through the tension adjustment mechanism 104', a pulley 109', and a traverser 108' on the other side.

The grooved roller 103 is a roller in which polyurethane resin is pressed into the periphery of a steel cylinder and grooves are cut on the surface of the roller at a substantially constant pitch. The saw wire 202 wound around the grooved roller can be driven by the grooved roller drive motor 110 in a unidirectional manner or in a reciprocating manner along the axis at a predetermined period.

The saw wire reels 107, 107' are rotationally driven by the saw wire reel drive motors 111, 111'. The tension applied to the saw wire 202 can be adjusted by controlling the speeds of the grooved drum drive motor 110 and the saw wire reel drive motors 111, 111' respectively.

2 feeds the workpiece W downwardly. The mechanism 105 shown in FIG. 3 has a workpiece holding mechanism 114 composed of a workpiece holding portion 112 and a workpiece plate 113 . The workpiece plate 113 is bonded to the workpiece W via a joining member (beam) 120 attached to the workpiece W.

When the workpiece W is cut, the workpiece W is held and relatively pressed down by the mechanism 105 for feeding the workpiece W downward, and is relatively fed toward the saw line formed by the saw wire 202 wound around the grooved drum 103.

This wire saw 201 is used, and the tension adjustment mechanism 104, 104' is used to apply appropriate tension to the saw wire 202, and the saw wire reel drives the motor 111, 111' to make the saw wire 202 move back and forth along the axis, and the cutting fluid supplied by the cutting fluid supply mechanism 206 is supplied to the mechanism 105 that feeds the workpiece W downward to feed the workpiece to cut the workpiece.

However, although the steel wire used in the wire saw is resistant to wear and tension, and the grooved drum uses a resin drum with a predetermined hardness to prevent damage to the wire, the wire may sometimes break during cutting of the workpiece due to wear and fatigue over time, and the workpiece cannot be cut any further.

In this case, it is known that the following method is performed: after the saw wire is separated from the workpiece cut, the broken wire is connected to the new wire. After that, the connected wire is sent to the saw wire reel 107' on the recovery side, each row of the saw wire is correspondingly engaged with each cut of the workpiece, and the saw wire row is arranged at the workpiece feed position when the wire is broken, and the cutting of the workpiece is restarted.

On the other hand, there is also a known method for cutting a workpiece, which is shown in FIG. 1 , in which a fixed abrasive saw wire 402 having diamond abrasives or the like fixed to the saw wire surface is used instead of a cutting fluid containing an abrasive. This method has been put into practical use to a certain extent for cutting small diameter ingots with a diameter of less than 150 mm.

In the cutting performed with the fixed abrasive saw wire 402, the fixed abrasive saw wire 402 is installed as shown in FIG1 instead of the steel wire saw wire 202 in the general wire saw 201 shown in FIG2. In addition, the following wire saw 101 is used: it includes a cooling liquid supply mechanism 106, and the cutting liquid supplied in the general wire saw 201 shown in FIG2 is replaced with a cooling liquid such as cooling water that does not contain an abrasive in the wire saw 101 shown in FIG1. In the cutting performed with the fixed abrasive saw wire 402, the general wire saw can be used directly.

Fixed abrasive saw wires may also break, and the following method must be performed in the same manner as free abrasive saw wires: the saw wire is separated from the workpiece cut, and the broken part is connected to the new wire, and the connected part is reeled to the saw wire reel 107' on the recovery side, and each row of the saw wire is correspondingly engaged with each cut of the workpiece, and the saw wire row is arranged at the workpiece feed position when the wire is broken, and the cutting of the workpiece is restarted. [Prior technical literature] [Patent literature]

Patent document 1: Japanese Patent Application Publication No. 9-262826

(Invent the problem you want to solve)

In the case of using the above-mentioned free abrasive wire saw, as shown in FIG4 (a), a clearance of the same width as the free abrasive G is formed between the saw wire 202 and the workpiece W, so it is relatively easy to correspond the rows of the saw wire to the cuts of the workpiece, and to arrange the saw wire rows at the workpiece feed position when the wire is broken. However, as shown in FIG4 (b), in the case of using the above-mentioned fixed abrasive wire saw, since there is no clearance between the fixed abrasive saw wire 402 and the workpiece W, there is the following problem: it is difficult to correspond the rows of the saw wire to the cuts of the workpiece.

In addition, if the saw wire and the workpiece are pulled too much, the saw wire may break. If the saw wire breaks, the saw wire must be reconnected and the fixed abrasive saw wire must be rewound, resulting in a huge loss.

The present invention is made in view of the above-mentioned problems, and aims to provide a method for restarting the operation of a wire saw, in which, when a wire saw with a fixed abrasive saw wire is used to cut a workpiece, even if the cutting of the workpiece is interrupted halfway due to an abnormality such as a wire break, the wire can be returned to the cutting position of the workpiece, and the wire breakage does not occur when the wire is set to the feed position. (Solution to the problem)

In order to achieve the above-mentioned purpose, the present invention provides a method for restarting the operation of a wire saw, wherein a fixed abrasive saw wire with abrasive fixed on its surface is hung on a multi-groove drum to form a saw wire array, the fixed abrasive saw wire is moved back and forth along an axial direction, and a workpiece is relatively pushed against the saw wire array to feed, and during the operation of the wire saw to cut the workpiece into a wafer shape, after the cutting of the workpiece is interrupted halfway through the workpiece, the cutting of the workpiece is restarted. The method is characterized in that the fixed abrasive saw wire, which has worn away the abrasive, is arranged at the feed position of the workpiece where the cutting of the workpiece is interrupted, and the cutting of the workpiece is restarted.

In the wire saw operation restart method of the present invention, since a gap can be formed between the workpiece and the saw wire by causing the abrasive of the fixed abrasive saw wire to wear, it is easy to engage each row of the saw wire with each cut of the workpiece, and the saw wire can be prevented from breaking when the saw wire is set to the feed position.

Furthermore, at this time, it is appropriate to set the diameter of the core wire of the aforementioned fixed abrasive saw wire as R, the diameter of the new wire, i.e., the aforementioned fixed abrasive saw wire, as R1, and the diameter of the saw wire after the aforementioned abrasive has been worn as R2, and then the aforementioned fixed abrasive saw wire that has been worn by the aforementioned abrasive, which satisfies R≦R2≦R+(R1-R)x0.1, is arranged at the feed position of the aforementioned workpiece where the cutting of the aforementioned workpiece is interrupted, and the cutting of the aforementioned workpiece is restarted.

According to this method, since a gap can be formed between the workpiece and the saw wire by causing the abrasive of the fixed abrasive saw wire to wear, it is easier to make each row of the saw wire correspond to each cut of the workpiece, and the saw wire breakage can be further suppressed. When the saw wire row is arranged at the workpiece feeding position when the wire breaks, it will not contact and pull the workpiece, which can suppress the generation of saw marks, damage and warp quality on the cut surface of the workpiece.

Furthermore, at this time, when the saw wire diameter of the fixed abrasive saw wire after the abrasive has been worn away is set to R3, the fixed abrasive saw wire after the abrasive has been worn away and R3 satisfies R2＜R3≦R2+（R1-R）x0.5 is preferably arranged at a position between the fixed abrasive saw wire after the abrasive has been worn away and R2 and the supplied new wire, and the cutting of the workpiece is restarted.

According to this method, since a gap can be formed between the workpiece and the saw wire by causing the abrasive of the fixed abrasive saw wire to wear, it is easier to make each row of the saw wire correspond to each cut of the workpiece when the saw wire is set to the feed position, and the saw wire breakage can be further suppressed. When the saw wire row is arranged at the workpiece feed position when the wire breaks, it will not contact the workpiece and cause pulling, which suppresses the generation of saw marks, damage and warp quality on the cut surface of the workpiece. In addition, because the change in the diameter of the saw wire is small, the load applied to the saw wire will not increase sharply during feed, so the wire breakage can be prevented at the time of cutting restart.

Furthermore, at this time, the grinding stone is preferably pushed relative to the fixed abrasive saw wire to wear the abrasive.

According to this method, the fixed abrasive on the surface of the fixed abrasive saw wire can be effectively removed, making it easier to return the saw wire to the cutting position of the workpiece. Therefore, it is easier to control the saw wire diameter so that the wire will not break again when the operation is restarted, and it can further prevent the saw wire from pulling the workpiece and causing saw marks, damage to the workpiece quality, and saw wire breakage.

In addition, at this time, the aforementioned grindstone should preferably be WA (White Alundum) grindstone.

This type of grinding stone can effectively remove the fixed abrasive on the surface of the fixed abrasive saw wire, making it easier to return the saw wire to the cutting position of the workpiece. Therefore, it is easier to control the saw wire diameter so that the wire will not break again when the operation is restarted, and it can further prevent the workpiece from pulling the saw wire and causing saw marks, damage to the workpiece quality, and saw wire breakage. (Effect of the invention)

As mentioned above, because the abrasive of the fixed abrasive saw wire is worn away, a gap can be formed between the workpiece and the saw wire, so it is easier to make each row of the saw wire correspond to each cut of the workpiece, and the saw wire can be further suppressed from breaking when the saw wire is set to the feed position. When the saw wire row is arranged at the workpiece feed position when the wire breaks, it will not contact the workpiece and cause pulling, which can suppress the generation of saw marks, damage and warp quality on the cut surface of the workpiece. In addition, because the change in the saw wire diameter is small, the load applied to the saw wire will not increase sharply during feeding, so it can also prevent the wire from breaking when the cutting is restarted.

(Preferred form of implementing the invention)

The present invention is described in detail below, but the present invention is not limited thereto.

As described above, when using a fixed abrasive wire saw, since there is no gap between the fixed abrasive saw wire 402 and the workpiece W, it is difficult to make each row of the saw wire correspond to each cut of the workpiece when the saw wire is set to the feed position, so a method is sought to prevent the saw wire from breaking.

The inventor of the present invention has repeatedly examined the above-mentioned problems and found a method for restarting the operation of a wire saw that can suppress the occurrence of saw wire breakage when the saw wire is set to a feed position, thereby completing the present invention. The method is a method in which a fixed abrasive saw wire having an abrasive fixed on its surface is hung around a multi-groove drum to form a saw wire array, the fixed abrasive saw wire moves back and forth along an axial direction, and a workpiece is relatively pushed against the saw wire array to feed the workpiece. During the operation of the wire saw for cutting the workpiece into a wafer shape, the cutting of the workpiece is interrupted halfway through the workpiece, and then the cutting of the workpiece is restarted. The method is characterized in that the fixed abrasive saw wire, which has worn away the abrasive, is arranged at the feed position of the workpiece where the cutting of the workpiece is interrupted.

The following is explained with reference to the diagram.

In the case of using a free abrasive wire saw, as shown in FIG4 (a), since a clearance of the width of the free abrasive G is formed between the saw wire 202 and the workpiece W, it is relatively easy to make each row of the saw wire correspond to each cut of the workpiece, and the saw wire row is arranged at the workpiece feed position when the wire is broken. However, in the case of using the above-mentioned fixed abrasive wire saw, as shown in FIG4 (b), since no clearance is generated between the fixed abrasive saw wire 402 and the workpiece W, each row of the saw wire can be made to correspond to each cut of the workpiece.

Therefore, the inventor of the present case has discovered a method for restarting the operation of a wire saw, wherein a fixed abrasive saw wire with abrasive fixed on its surface is hung on a multi-grooved drum to form a saw wire array, the fixed abrasive saw wire is moved back and forth along an axial direction, and a workpiece is relatively pushed against the saw wire array to feed, and during the operation of the wire saw for cutting the workpiece into a wafer shape, after the cutting of the workpiece is interrupted halfway through the workpiece, the cutting of the workpiece is restarted. The method is characterized in that the fixed abrasive saw wire, which has worn away the abrasive, is arranged at the feed position of the workpiece where the cutting of the workpiece was interrupted, and the cutting of the workpiece is restarted.

In the wire saw operation restart method of the present invention, since a gap is formed between the workpiece and the saw wire by causing the abrasive of the fixed abrasive saw wire to be worn, it is easy to engage each row of the saw wire with each cut of the workpiece, and the saw wire can be prevented from breaking when the saw wire is set to the feed position.

Furthermore, the inventors of this case have found that when the diameter of the core wire of the fixed abrasive saw wire is set to R, the diameter of the new wire, i.e., the fixed abrasive saw wire, is set to R1, and the diameter of the saw wire after the abrasive is worn is set to R2, by placing the fixed abrasive saw wire that has been worn by the abrasive and R2 satisfies R≦R2≦R+(R1-R)x0.1 at the feed position of the workpiece that interrupts the cutting of the workpiece, the saw wire breakage can be further suppressed. Moreover, the saw wire will not come into contact with the workpiece and be pulled, and the generation of saw marks, damage, warp quality, etc. on the cut surface of the workpiece can be suppressed.

Further investigation revealed that there were no problems until the machine was positioned at the workpiece feed position, but sometimes the wire would break again immediately after the machine was restarted.

After investigating the broken wire, it was found that the wire broke at the time when the fixed abrasive saw wire was worn to meet the diameter of R2 and the boundary of the new wire passed through the workpiece. Therefore, the inventor of this case speculated that when the diameter of the fixed abrasive saw wire was greatly different from that of the new wire, the feed of the workpiece before and after the drop part became larger, and the load on the saw wire increased sharply, causing the wire breakage.

Therefore, the inventors of the present case have discovered a method for restarting the operation of a wire saw as a method for preventing the wire from being disconnected again when restarting the operation. The method is to set the saw wire diameter after the abrasive wear of the fixed abrasive saw wire different from R2 to R3, and then arrange the fixed abrasive saw wire that has been worn out with R3 satisfying R2＜R3≦R2+（R1-R）x0.5 at a position between the fixed abrasive saw wire that has been worn out with R2 and the supplied new wire, so as to restart the cutting of the workpiece.

According to this method, since the saw wire diameter increases in the order of R2=＞R3=＞new wire when the saw wire passes through the workpiece, the change in the saw wire diameter is smaller than the case where the saw wire is engaged in the order of R2=＞new wire. The load applied to the saw wire during feed will not increase sharply, which can prevent the saw wire from breaking.

In order to wear the fixed abrasive saw wire, it is preferable to push the grindstone relatively against the fixed abrasive saw wire. In addition, the grindstone is preferably a WA (White Alundum) grindstone.

If this operation restart method is used, the fixed abrasive on the surface of the fixed abrasive saw wire can be effectively removed, making it easier to return the saw wire to the cutting position of the workpiece. In addition, the saw wire diameter can be easily controlled so that the saw wire will not be disconnected again when setting the saw wire to the feed position or when the operation is restarted. [Example]

Hereinafter, the present invention will be specifically described by using embodiments and comparative examples of the present invention, but the present invention is not limited thereto.

Using the wire saw shown in Figure 1, start cutting a cylindrical workpiece under the common conditions in Table 1, and interrupt the cutting midway. Then, remove the wire from the workpiece cut and reel the wire onto the reel until the unused portion of the wire reaches the workpiece.

[Table 1] Saw wire Core diameter 0.140mm Diamond particle size 10-20μm Saw wire outer diameter 0.174mm Abrasive Attachment Method Nickel electroplating Workpiece Diameter 301mm Length 300mm Saw wire travel conditions during cutting Saw wire tension 25N Saw wire travel speed Maximum 1500m/min. Saw line advance 2114m Saw line setback 2086m Saw wire usage 9000m Workpiece feeding conditions during cutting Workpiece feed speed 0.32mm/min Feed depth 310mm Cooling water Liquid Seed Water + glycol mixture Coolant flow About 150L/min. Coolant temperature 23℃

(Example 1) An attempt was made to use the grindstone in Table 2 to wear the saw wire to the conditions in Table 3, so that each row of the saw wire was engaged with each cut of the workpiece, and the saw wire row was arranged at the workpiece feed position when the cutting was interrupted.

[Table 2] millstone Type WA Number #200

[Table 3] Saw wire core diameter R Saw wire diameter R1 R+(R1-R)x0.1 Saw wire diameter after wear R2 Condition 1 0.14mm 0.174mm 0.1434mm 0.155mm Condition 2 0.145mm Condition 3 0.143mm Condition 4 0.141mm Condition 5 0.140mm

(Comparative example) An attempt was made to prevent the saw wire from being worn and to align each row of the saw wire with each cut of the workpiece, and to arrange the saw wire row at the workpiece feed position when the cutting of the workpiece is interrupted.

The results of Example 1 and the comparative example are shown in Table 4. Saw marks and saw line breakage occurred in the comparative example. For Example 1, no saw line breakage occurred under any conditions, and no saw marks or saw line breakage occurred when conditions 3 to 5 of "R≦R2≦R+(R1-R)×0.1" were satisfied.

[Table 4] Comparison Example Embodiment 1 Condition 1 Condition 2 Condition 3 Condition 4 Condition 5 Saw marks occur have have have without without without The saw wire breaks when positioning towards the incision position have without without without without without

(Example 2) Use the grindstone in Table 2 to wear the saw wire to the conditions in Table 5, and engage each row of the saw wire to each cut of the workpiece, and arrange the saw wire row at the workpiece feed position when the cutting of the workpiece is interrupted, and restart the cutting.

[Table 5] Before saw wire wear treatment After saw wire wear treatment Core diameter R Diameter R1 Diameter R2 R2+(R1-R)x0.5 Diameter R3 Condition 1 0.14mm 0.174mm 0.143mm 0.16mm 0.174mm Condition 2 0.165mm Condition 3 0.16mm Condition 4 0.155mm Condition 5 0.15mm

The results of Example 2 are shown in Table 6. When conditions 3 to 5 of "R2＜R3≦R2+（R1-R）x0.5" are satisfied, disconnection does not occur during operation restart.

[Table 6] Embodiment Condition 1 Condition 2 Condition 3 Condition 4 Condition 5 Disconnection during restart have have without without without

In addition, the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are illustrative only, and those having substantially the same structure and exerting the same function and effect as the technical concept described in the scope of the patent application of the present invention are all included in the technical scope of the present invention.

101: Wire saw (fixed abrasive type) 103: Grooved drum 104,104’: Tension adjustment mechanism 105: Mechanism for feeding the workpiece downward 106: Cooling liquid supply mechanism 107,107’: Saw wire reel 108,108’: Wire guide 109,109’: Pulley 110: Grooved drum drive motor 111,111’: Saw wire reel drive motor 112: Workpiece holding part 113: Workpiece plate 114: Workpiece holding mechanism 120: Joint member (beam) 201: Wire saw (free abrasive type) 202: Saw wire (high-tension steel wire) 206: Cutting fluid supply mechanism 402: Fixed abrasive saw wire W: Workpiece G: Abrasive

FIG1 shows an example of a fixed abrasive wire saw. FIG2 shows an example of a free abrasive wire saw. FIG3 shows a mechanism for feeding a workpiece downward. FIG4 (a) and (b) are cross-sectional views of a workpiece and a saw wire when the saw wire is positioned at a workpiece feed position in order to restart cutting of the workpiece.

101: Wire saw (fixed abrasive type)

103: Grooved drum

104,104’: Tension adjustment mechanism

105: Mechanism for feeding the workpiece downward

106: Cooling liquid supply mechanism

107,107’: Saw reel

108,108’: Wire guide

109,109’: pulley

110: Grooved drum drive motor

111,111’: Saw reel drive motor

402: Fixed abrasive saw wire

W: Workpiece

Claims (4)

A method for restarting the operation of a wire saw is provided, wherein a fixed abrasive saw wire with abrasive fixed on its surface is hung on a multi-groove drum to form a saw wire array, the fixed abrasive saw wire is moved back and forth along an axial direction, and a workpiece is relatively pushed against the saw wire array to feed, and the workpiece is cut into a wafer shape. During the operation of the wire saw, when the cutting of the workpiece is interrupted halfway through the workpiece, the method restarts the cutting of the workpiece. The method is characterized in that the fixed abrasive saw wire, which has worn away the abrasive, The cutting of the workpiece is restarted by placing the saw wire at the feed position of the workpiece where the cutting of the workpiece is interrupted; when the diameter of the core wire of the fixed abrasive saw wire is set to R, the diameter of the new wire, i.e., the fixed abrasive saw wire, is set to R1, and the diameter of the saw wire after the abrasive has been worn is set to R2, the fixed abrasive saw wire that has been worn by the abrasive and R2 satisfies R≦R2≦R+(R1-R)x0.1 is placed at the feed position of the workpiece where the cutting of the workpiece is interrupted, and the cutting of the workpiece is restarted. The method for restarting the operation of a wire saw as claimed in claim 1, wherein when the saw wire diameter after the abrasive of the fixed abrasive saw wire is worn out and is different from R2, the fixed abrasive saw wire that has worn out and whose R3 satisfies R2<R3≦R2+(R1-R)x0.5 is arranged between the fixed abrasive saw wire that has worn out and satisfies R2 and the new wire supplied, and the cutting of the workpiece is restarted. A method for restarting the operation of a wire saw as claimed in claim 1 or 2, wherein the grinding stone is pushed relatively against the fixed abrasive saw wire to wear the abrasive. A method for restarting the operation of a wire saw as claimed in claim 3, wherein a WA (White Alundum) grindstone is used as the grindstone.

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