JP2010030000A - Structure of groove roller - Google Patents

Abstract

The present invention relates to a structure of a groove roller provided in a wire saw cutting device for slicing an ingot, and it is possible to reduce the influence on the cutting performance of a decrease in wire diameter due to wear during cutting.
Wire saw cutting in which a wire is spirally wound between groove rollers having a plurality of grooves arranged in parallel so as to sandwich an ingot, and the ingot is sliced while supplying slurry to the reciprocating wire. In the structure of the groove roller 21 provided in the apparatus, the arrangement pitch of the plurality of grooves 22 is reduced toward the downstream side corresponding to the diameter reduction of the wire worn when slicing the ingot. At the same time, the large number of grooves 22 are configured such that the depth decreases as they go downstream.
[Selection] Figure 1

Description

  The present invention relates to a groove roller structure provided in a wire saw cutting device for slicing an ingot.

  In general, a silicon wafer (semiconductor wafer) is obtained by slicing a silicon single crystal ingot into a wafer having a predetermined thickness in a slicing process after cutting and separating the top and tail, followed by processes such as outer diameter grinding and orientation flat processing. The obtained material wafer is manufactured by flattening its surface with high precision through a grinding process, an etching process and a polishing process.

For slicing in the slicing step, cutting with a wire saw cutting device (simply referred to as a wire saw) such as a piano wire is adopted as the diameter of the wafer increases.
For example, as shown in FIG. 3, the wire saw cutting device described in Patent Document 1 includes three groove rollers 1 to 3, one of which is connected to the drive motor 4. The wire 5 that circulates around the groove rollers 1 to 3 is unwound from one wire reel 6 and wound around the other wire reel 7. At this time, the wire 5 advances only in one direction, and the wire There is a reciprocating traveling method in which 5 is wound around one reel 7 while reciprocating between the wire reels 6 and 7. Further, tension is applied to the wire 5 by the tensioner 8 so as to go around the rollers 1 to 3 while being pulled.

  The ingot 9 to be sliced is held by the holder 10 and disposed between the groove rollers 1 and 2, and is sliced into a plurality of wafers by the wire 5 while being lowered together with the holder 10. At this time, the slurry 11 containing abrasive grains is supplied to the wire 5 in order to efficiently perform the slicing operation. The slurry 11 is supplied from the slurry tank 12 through the supply pipe 13 to the wire 5 from the nozzle 14, and then collected by the pan 15 and returned to the slurry tank 12. Further, in order to cool the slurry 11, the slurry 11 is circulated between the heat exchanger 16 and the slurry tank 12. Groove rollers 1 to 3 have grooves formed on the peripheral surface at a predetermined pitch, and the wire 5 enters the grooves. Therefore, the wire 5 travels at a pitch corresponding to the groove pitch between the groove rollers 1 and 2 located on both sides of the ingot 9. A wafer is cut from the ingot 9 with a thickness corresponding to this pitch.

The wire saw cutting method is classified into the one-way traveling method and the reciprocating traveling method as described above from the traveling form of the wire 5.
In the reciprocating traveling method, when the ingot 9 is sliced as shown in FIG. 4A, the wire 5 is reciprocated as shown in FIG. 4B. For example, after the wire 5 is fed out from the groove roller 1 on the new line supply side by 300 m, the wire 5 is caused to travel 200 m in the opposite direction, and then from the groove roller 1 on the new line supply side to the groove roller 2 on the wire recovery side. The wire 5 is sent out by 300 m. By repeating this reciprocating travel, the wire 5 as a whole is sequentially sent from the groove roller 1 to the groove roller 2 at a speed of about 100 m / min.

For this reason, the reciprocating traveling method requires less storage dose to store the wire 5 on the reel 6 than the one-way traveling method, and the ingot is sliced from the advantage that the wafer cut out from the ingot 9 does not become a wedge type. It has become the mainstream of wire saw cutting.
On the other hand, however, the reciprocating method has a drawback that the thickness of the wafer varies between the new wire supply side and the wire recovery side due to the wear of the wire 5. This is because the wire 5 has a larger amount of wear on the wire collection side than on the new line supply side, so the effective diameter of the wire 5 tends to be small and the wafer thickness tends to be large.

  That is, as shown in FIG. 5, when the wire diameter din on the entry side of the supply side roller 1 is compared with the wire diameter dout on the exit side of the collection side roller 2, the wire 5 is compared with the case of unidirectional cutting. The diameter decrease Δd (= din−dout) of itself becomes much larger. Such a decrease in the diameter of the wire 5 affects the thickness variation of the wafer 17 cut out from the ingot 9. The maximum thickness of the wafer W1 cut out from the ingot 9 on the entry side when the ingot is sliced by the wire 5 fed while being guided by the grooves engraved on the groove rollers 1 and 2 with the maximum pitch a to the minimum pitch b. t1 can be calculated as a-din if the cutting allowance by the abrasive grains is ignored, and the maximum thickness t2 of the wafer W2 cut out from the ingot 9 on the exit side can be calculated as b-dout.

Paying attention to this point, Patent Document 1 discloses that the maximum pitch of grooves provided on the new line supply side of each groove roller is a, the minimum pitch of grooves provided on the wire collection side is b, and wears when slicing the ingot. A technique for gradually reducing the pitch of the grooves of each groove roller from the new line supply side toward the collection side so that the wire diameter can be circulated while maintaining the relationship of b = a−Δd, where Δd is the wire diameter decrease. Has been proposed.
JP-A-10-249701

However, if the wire is greatly worn from the new line supply side to the collection side, it is not sufficient to gradually decrease the pitch of the groove rollers from the new line supply side to the collection side.
In other words, the ingot is guided by the grooves of the groove roller and is cut by the portions of the wire that reciprocate in parallel with each other, but by setting the pitch of the groove roller in consideration of the amount of wire wear, Although the thickness of the wafer to be cut can be predetermined, the wear of the wire, that is, the reduction of the diameter of the wire is caused by the ingot coming into contact with each portion of the wire that is parallel to each other and cuts the ingot. Since the position (vertical direction position in FIG. 3) is minutely changed, the cutting is delicately affected.

  FIG. 6 is a schematic diagram for explaining the effect of reducing the wire diameter due to wear during cutting. As shown in FIG. 6, the ingot 9 is parallel to each other and horizontally below each part 5a to 5e of the wire 5 as shown in FIG. Is lowered and cut off. In addition, although each part of the wire 5 is actually arranged in a large number at a pitch corresponding to the thickness of the wafer, only the wire parts 5a to 5e are shown here for convenience, and the reduction of the wire diameter is extremely described. Yes.

  Each of the wire portions 5a to 5e is reciprocated and cut while entering the ingot 9 in its upper half, but when the wire diameter decreases toward the downstream side, as shown in FIG. In the grooves 20a to 20e having a constant groove depth and a constant groove angle, the wire center becomes lower as going to the downstream side, and the upper half of the wire portions 5a to 5e entering the ingot 9 The position in the height direction becomes a lower position as it goes downstream, and the approach depth becomes shallower.

This tendency becomes more prominent in the later stage of cutting in which the wire diameter decreases, and the time difference between the upstream side and the downstream side of the completion of cutting also occurs. That is, even if the cutting is completed on the upstream side, a state in which the cutting is not completed on the downstream side also occurs.
Considering the cutting performance, it is desirable to make the depth of penetration of the upstream and downstream wires into the ingot as uniform as possible.

  The present invention has been devised in view of such a problem, and provides a groove roller structure capable of reducing the influence on the cutting performance of a decrease in wire diameter due to wear during cutting. Objective.

  In order to achieve the above object, the structure of the groove roller of the present invention is such that the wire reciprocally travels by spirally winding a wire between groove rollers having a plurality of grooves arranged in parallel so as to sandwich an ingot. The groove roller structure provided in a wire saw cutting device for slicing the ingot while supplying slurry to the groove, wherein the pitch of the plurality of grooves reduces the diameter of the wire worn when slicing the ingot Corresponding to the minute, the groove is reduced toward the downstream side, and the plurality of grooves are formed to have a depth that decreases toward the downstream side.

The plurality of grooves are V-grooves having a substantially V-shaped cross section, and the double-sided angle of the V-groove is preferably set to be smaller toward the downstream side.
Further, another structure of the groove roller of the present invention is such that a wire is spirally wound between groove rollers having a plurality of grooves arranged in parallel so as to sandwich an ingot, and slurry is applied to the reciprocating wire. The structure of the groove roller provided in a wire saw cutting device for slicing the ingot while being supplied, wherein the arrangement pitch of the plurality of grooves corresponds to the reduced diameter of the wire that is worn when slicing the ingot. The multiple grooves are reduced in size toward the downstream side, and the plurality of grooves are V-grooves having a substantially V-shaped cross section.
The double-sided angle of the groove is characterized by being set smaller as it goes downstream.

  According to the structure of the groove roller of the present invention, the arrangement pitch of a large number of grooves of the groove roller is reduced toward the downstream side corresponding to the diameter reduction of the wire worn when slicing the ingot. The thickness of the wafer formed by slicing is made uniform, and many grooves are formed with a depth that decreases toward the downstream side. Accordingly, the approach depth of the wire that moves forward and backward is made uniform, and each slice portion can be sliced under closer conditions, so that the cutting performance is improved.

  When adopting V-grooves for a large number of grooves of the groove roller, by setting the double-sided angle of the V-groove to be smaller toward the downstream side, it becomes difficult for the diameter-reduced wire to sink into the V-groove, The approaching depth of the wire that moves forwards and backwards is made uniform, so that each slice portion can be sliced under closer conditions, and cutting performance is improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a structure of a groove roller according to an embodiment of the present invention. FIG. 1 is a front view of the groove roller and an enlarged cross-sectional view of a main part thereof, and FIG. 2 is a cross-sectional view of the groove. In addition, since the wire saw cutting device itself concerning this embodiment is comprised similarly to the conventional one, it demonstrates here using FIG.

[Wire saw cutting device]
As shown in FIG. 3, the wire saw cutting device according to the present embodiment includes a plurality (here, three) of groove rollers 1 to 3, one of which is connected to the drive motor 4. The wire 5 that circulates around the groove rollers 1 to 3 is unwound from one wire reel 6 and wound around the other wire reel 7. At this time, the wire 5 advances only in one direction, and the wire There is a reciprocating traveling method in which 5 is wound around one reel 7 while reciprocating between the wire reels 6 and 7. Further, tension is applied to the wire 5 by the tensioner 8 so as to go around the rollers 1 to 3 while being pulled.

The ingot 9 to be sliced is held by the holder 10 and disposed between the groove rollers 1 and 2, and is sliced into a plurality of wafers by the wire 5 while being lowered together with the holder 10. At this time, the slurry 11 containing abrasive grains is supplied to the wire 5 in order to efficiently perform the slicing operation. The slurry 11 is supplied from the slurry tank 12 through the supply pipe 13 to the wire 5 from the nozzle 14, and then collected by the pan 15 and returned to the slurry tank 12. Further, in order to cool the slurry 11, the slurry 11 is circulated between the heat exchanger 16 and the slurry tank 12. Groove rollers 1 to 3 have grooves formed on the peripheral surface at a predetermined pitch, and the wire 5 enters the grooves. Therefore, the wire 5 travels at a pitch corresponding to the groove pitch between the groove rollers 1 and 2 located on both sides of the ingot 9. A wafer is cut from the ingot 9 with a thickness corresponding to this pitch.
Although the wire saw cutting method is classified into the one-way traveling method and the reciprocating traveling method as described above from the traveling form of the wire 5, the reciprocating traveling method is adopted for the wire saw cutting apparatus.

[Groove roller]
As shown in FIG. 1A, the groove roller 21 of the present embodiment applied to the above-described groove rollers 1 to 3 has a large number of grooves 22 on the outer periphery, and guides the wire through these grooves 22. The pitch (interval) at which these grooves 22 are arranged is reduced toward the downstream side corresponding to the diameter reduction of the wire worn when slicing the ingot.

  In other words, the wire diameter din of the most upstream portion of the wire (the wire entering side of the supply side roller 1) and the wire diameter dout of the most downstream portion of the wire (the wire exit side of the collecting side roller 2) of the wire 5 For the diameter reduction Δd (= din−dout), the groove interval (maximum pitch) a at the most upstream part of the wire (the wire entering side of the supply side roller 1) and the most downstream part of the wire (the wire of the collection side roller 2) The pitch of the grooves 22 of each groove roller 21 is the same as in Patent Document 1 so that the wire spacing is maintained while the groove interval (minimum pitch) b on the exit side maintains the relationship b = a−Δd. It is set gradually smaller from the new line supply side to the collection side.

In addition, as shown in FIG. 1B, which is an enlarged view of a main part schematically shown corresponding to each part ae of FIG. 1A, in the case of this groove roller, a large number of grooves 22 (22a-22e). ) Is substantially V in cross section
Each of the V-shaped grooves has a depth D of each groove 22 and an angle α (see FIG. 2) formed by both surfaces of the V-groove 22 as it goes downstream (that is, from the groove 22a to the groove 22e). Is set to be smaller. The grooves 22 are actually arranged in a large number at a pitch corresponding to the thickness of the wafer obtained after slicing, but only the grooves 22a to 22e are shown here for the sake of convenience, and the reduction of the groove depth is extremely described. ing.

  Such setting of the depth D and the V angle α focuses on the fact that the position of the wire 5 in the groove 22 changes because the diameter of the wire 5 decreases toward the downstream side. That is, as already described with reference to FIG. 7, when the depth D and the V angle α are constant, the wire 5 sinks into the groove 22 as the diameter of the wire 5 decreases. In the case of the groove rollers 1 and 2 (see FIG. 3) that directly support the wire 5, the position of the guiding wire 5 in the vertical direction (position of the wire axis) becomes lower toward the downstream side. Since the cutting of the ingot is performed on the upper surface of the wire 5, the position of the upper surface of the wire with respect to the wire axis becomes lower toward the downstream side. In combination, the depth D and the V angle α of the V-groove 22 are set to become smaller toward the downstream side in order to suppress the change of the wire upper surface position for cutting the ingot. It is.

  The event that the diameter of the wire 5 decreases toward the downstream side does not occur at the start of ingot slicing, but progresses as the ingot slice progresses. For example, the wire 5 at the time when about half of the ingot is sliced. In this case, the depth D and the V angle α of the V groove 22 may be set so that the upper surface position of the wire for cutting the ingot is substantially the same on the upstream side and the downstream side. preferable.

[Action and effect]
Since the structure of the groove roller according to the embodiment of the present invention is configured as described above, the arrangement pitch of the plurality of grooves 22 of the groove roller 21 corresponds to the diameter reduction of the wire 5 that wears when slicing the ingot. Correspondingly, the thickness of the wafer formed by slicing is made uniform by being reduced toward the downstream side.

  The numerous grooves 22 are formed so that the depth D decreases toward the downstream side, and the V angle α is also decreased toward the downstream side, and the height of the upper surface position of the wire 5 for cutting the ingot 9 is increased. Since the change between the upstream side and the downstream side is reduced, the penetration depth of the wire 5 that moves in parallel and moves back and forth in parallel to the ingot 9 is made uniform, and slices are sliced under closer conditions. And cutting performance is improved.

[Others]
As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various deformation | transformation is possible in the range which does not deviate from the meaning of this invention.

For example, in the above embodiment, the depth D and the V angle α of the V groove 22 are set so as to decrease as they go downstream, but the depth D and the V angle α of the V groove 22 Only one of them may be set so as to become smaller toward the downstream side.
In addition, the groove 22 is not limited to the V-groove, and a groove having a semicircular cross section may be applied. In this case, the guide position of the wire cannot be adjusted by the V angle α. do it.

It is a figure which shows the structure of the groove roller as one Embodiment of this invention, Comprising: (a) is the front view, (b) is the principal part enlarged view. It is sectional drawing explaining the groove | channel of the groove roller as one Embodiment of this invention. It is a perspective view which shows the wire saw cutting device concerning background art. It is a figure concerning background art, (a) is a schematic perspective view which shows the state which has cut | disconnected the ingot, reciprocatingly moving a wire, (b) is a figure explaining driving | running | working of a wire. It is a figure concerning background art, Comprising: It is explanatory drawing of the state which is carrying out the wire saw cutting | disconnection of the ingot. It is a figure explaining the subject of the present invention, and is a typical sectional view showing a wire position in an ingot at the time of wire saw cutting. It is a figure explaining the subject of this invention, Comprising: It is typical sectional drawing which shows the wire position in the groove | channel of a groove roller.

Explanation of symbols

1 to 3 Groove roller 4 Drive motor 5 Wire 6, 7 Wire reel 8 Tensioner 9 Ingot 10 Holder 11 Slurry 12 Slurry tank 13 Supply pipe 14 Nozzle 15 Pan 16 Heat exchanger 21 Groove roller 22 Groove (V groove)
D Depth of groove 22 α V angle (angle formed by both surfaces of V groove 22)

Claims (3)

It is equipped with a wire saw cutting device that slices the ingot while supplying the slurry to the wire that reciprocally travels by rotating the wire spirally between groove rollers having a plurality of grooves arranged in parallel so as to sandwich the ingot The groove roller structure
The arrangement pitch of the plurality of grooves is reduced toward the downstream side corresponding to the diameter reduction of the wire that is worn when slicing the ingot, and
The groove roller structure is characterized in that a depth of each of the plurality of grooves decreases toward the downstream side. The plurality of grooves are V-grooves having a substantially V-shaped cross section,
The groove roller structure according to claim 1, wherein a double-sided angle of the V groove is set to be smaller toward a downstream side. It is equipped with a wire saw cutting device that slices the ingot while supplying the slurry to the wire that reciprocally travels by rotating the wire spirally between groove rollers having a plurality of grooves arranged in parallel so as to sandwich the ingot The groove roller structure
The arrangement pitch of the plurality of grooves is reduced toward the downstream side corresponding to the diameter reduction of the wire that is worn when slicing the ingot, and
The plurality of grooves are V-grooves having a substantially V-shaped cross section,
The groove roller structure is characterized in that a double-sided angle of the V-groove is set to be smaller toward the downstream side.

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