JPWO2009104222A1 - Wire saw and workpiece cutting method - Google Patents

Abstract

The present invention holds a workpiece via at least a wire that is wound around a plurality of grooved rollers and reciprocates in the axial direction, a nozzle that supplies a slurry, a contact plate, and a work plate that holds the corresponding plate. A wire saw that includes a workpiece feeding device that feeds to a wire while feeding slurry from a nozzle, presses the workpiece held by the workpiece feeding device against the wire, cuts and feeds the workpiece, and cuts the workpiece into a wafer shape. The feeding device has a workpiece holding portion, and provides a wire saw in which the maximum width of the lower end surface of the workpiece holding portion is larger than the width of the workpiece to be cut. This prevents the portion of the workpiece that has been cut into a wafer shape from accelerating by the slurry falling from the side of the workpiece on the side of the workpiece and falling from the side of the workpiece holder, and sliced. A wire saw is provided that can improve the warp of a wafer.

Description

The present invention relates to a wire saw for cutting a large number of wafers from a workpiece (for example, a silicon ingot, a compound semiconductor ingot, etc.) using a wire saw, and a method for cutting the workpiece.

  Conventionally, a wire saw is known as means for cutting a wafer from a silicon ingot or a compound semiconductor ingot. In this wire saw, a plurality of cutting wires are wound around a plurality of rollers to form a wire row, the cutting wires are driven at a high speed in the axial direction, and slurry is appropriately supplied while the wire is being supplied. By cutting and feeding the workpieces to the row, the workpieces are cut at the same time at each wire position (see Japanese Patent Application Laid-Open No. 9-262826).

  More specifically, the entire work piece in a state where the contact plate is bonded to substantially the entire area in the axial direction of the work in a part of the side surface of the work, and the work plate holding the contact plate is held by the work holding unit of the work feeding device. Is cut and fed, and cut by a cutting wire from the side opposite to the contact plate. At this time, a method of pressing the workpiece against the wire row is known by a method of pressing the workpiece against the wire row from above and a method of pressing from below. However, in cutting the semiconductor silicon ingot, the workpiece is wired. The method of pressing the row from above is the mainstream.

Here, FIG. 10 shows an outline of an example of a conventional general wire saw.
As shown in FIG. 10, a wire saw 101 mainly includes a wire 102 for cutting a workpiece, a grooved roller 103 around which the wire 102 is wound, a mechanism 104 for applying tension to the wire 102, and a workpiece to be cut. , And a mechanism 106 for supplying slurry at the time of cutting.

  The wire 102 is fed out from one wire reel 107 and passes through a traverser 108 and a tension applying mechanism 104 including a powder clutch (constant torque motor 109), a dancer roller (dead weight) (not shown), and the like, and a grooved roller 103. In. The wire 102 is wound around the grooved roller 103 about 300 to 400 times, and then wound around the wire reel 107 ′ through the other tension applying mechanism 104 ′.

  Further, the grooved roller 103 is a roller in which polyurethane resin is press-fitted around a steel cylinder and grooves are cut at a constant pitch on the surface thereof, and a wound wire 102 is predetermined by a driving motor 110. It can be driven in the reciprocating direction at a certain cycle.

When the workpiece is cut, the workpiece is pushed down while being held by a workpiece feeding device 105 as shown in FIG. 11 and fed to the wire 102 wound around the grooved roller 103. The workpiece feeding device 105 includes a workpiece holding unit 111 for holding a workpiece, an LM guide 112 for feeding the workpiece downward, and a workpiece feeding main body 113. The workpiece feeding device 105 is controlled by the computer along the LM guide 112. By driving the main body 113, the work held by the work holding part 111 can be sent out at a feed speed programmed in advance.
The workpiece is bonded to the contact plate 114, and the contact plate 114 is held by the work plate 115. Then, the workpiece is held by the workpiece holding unit 111 (in this example, the clamper 116 that holds the workpiece plate 115) via the contact plate 114 and the workpiece plate 115.

  Further, as shown in FIG. 10, a nozzle 117 is provided in the vicinity of the grooved roller 103 and the wound wire 102 so that slurry can be supplied from the slurry tank 118 to the wire 102 at the time of cutting. . A slurry chiller 119 is connected to the slurry tank 118 so that the temperature of the slurry to be supplied can be adjusted.

  Using such a wire saw 101, an appropriate tension is applied to the wire 102 using the wire tension applying mechanism 104, and the workpiece is cut and fed by the workpiece feeding device 105 while the wire 102 is traveling in the reciprocating direction by the driving motor 110. To slice.

However, when a workpiece is cut into a wafer shape using a general conventional wire saw as described above, and the shape of the cut wafer is examined, a large warp has occurred. Warp is one of the important qualities in the cutting of semiconductor wafers, and further reduction is desired as product quality requirements increase.

  Therefore, the inventor conducted a detailed investigation of the shape of the cut wafer. In particular, the deterioration of Warp in the vicinity of both end faces of the workpiece was remarkable. In the second half, we found that the Warp shape was significantly worse.

  In order to investigate the cause of the deterioration of the Warp shape, the state of the workpiece being cut was observed. The slurry is supplied to the workpiece cutting unit by driving the wire in the axial direction at high speed while applying the slurry from above the wire row to the workpiece side position of the wire row. At this time, it was found that most of the slurry adhered to the wire and carried to the vicinity of the workpiece cutting portion collided with the side surface of the workpiece at the cut-in portion of the workpiece and dropped below the workpiece.

  In particular, in a semiconductor silicon ingot, since the workpiece has a cylindrical shape, when the workpiece is cut from the workpiece cutting start portion to the center portion of the workpiece, the slurry that collides with the side surface of the workpiece quickly moves downward from the wire cut portion. Fall. FIG. 12 shows the flow of slurry when the center portion is being cut from the cutting start portion of the workpiece. In addition, in FIG. 12, the example when the wire 102 is running from the left side toward the right side is shown.

  However, when the workpiece is further cut and the portion after the center of the workpiece is cut, the slurry scatters toward the upper side of the workpiece on the side surface of the cylindrical workpiece, and then falls downward, below the wire. It was found that a part of a workpiece cut into a wafer shape vibrates in a direction perpendicular to the wire row (bellows motion).

  Here, FIG. 13 shows a state when the slurry flows into the portion cut by the wire. This is a view of the workpiece side as seen from the direction along the wire row. The slurry that flows into the part cut by the wire loses moisture during movement due to cutting heat, etc., and has a higher viscosity than when it was first supplied to the wire. The portion that has accumulated in the vicinity of the lower end (near the cutting start portion) (see P in FIG. 13) and has already been cut into the wafer shape is likely to stick to each other. On the other hand, in the vicinity of the center of the workpiece (see Q in FIG. 13), the fulcrum is the vicinity of the lower end of the workpiece that is cut into a wafer shape and stuck to each other as described above, and the upper end of the workpiece that has not been cut yet. During the cutting, the bellows moves in a direction perpendicular to the wire row. Moreover, it was found that the amplitude of the bellows movement increases as it approaches the end face side of the workpiece.

  Furthermore, when a further detailed investigation was conducted on the state in which the slurry scattered above the workpiece fell, a part of the slurry scattered above the workpiece was fixed to the workpiece holding part that fixedly supports the workpiece plate above the workpiece, that is, For example, in FIG. 11, it collides with the side surface of the clamper 116, and then flows down along the side surface of the clamper and drops on a specific part of the workpiece.

FIG. 14 shows a state in which the slurry is scattered on the side surface of the clamper which is the work holding unit. As shown in FIG. 14, when the part after the center of the work is cut, the slurry is scattered upward and part of the work reaches the side surface 116 s of the clamper 116.
Here, even if splashed slurry is dropped on a specific part of the workpiece, if the workpiece where the slurry has dropped is still in a block-like state before cutting, the quality of the wafer to be cut is not particularly affected. .
However, as shown in FIG. 15, when the workpiece at the position where the slurry has dropped from the side surface 116s of the clamper 116 as the workpiece holding portion has already been cut into a wafer shape, the dropped slurry is between the wafers. The inventor has discovered that it is easy to enter, thereby causing a bellows motion in the wafer, resulting in a worsening of the Warp of the cut wafer.

  The warp shape deteriorates particularly at the latter half of the cutting position of the workpiece, in the latter half of the cutting, caused by the dripping of the slurry concentrated from the side surface of the clamper to the portion of the workpiece that has already been cut and becomes a wafer. This is because of the bellows movement of the workpiece that has already been cut, and the Warp deteriorates particularly on both end faces of the work because the work bellow movement is larger on both end faces than the center of the work. is there.

  Therefore, the present invention has been made in view of the above-described problems, and is cut into a wafer shape by a slurry that is scattered at the wire cutting portion on the side surface of the workpiece and falls from the side surface of the workpiece holding portion. An object of the present invention is to provide a wire saw capable of preventing a portion of a workpiece from performing bellows movement and improving Warp of a sliced wafer.

In order to achieve the above object, the present invention is bonded to at least a wire wound around a plurality of grooved rollers and reciprocating in the axial direction, a nozzle for supplying slurry to the wire, and a workpiece to be cut. A workpiece feed device that feeds the wire to the wire by pushing down while holding the workpiece through the contact plate that holds the corresponding plate and supplying the slurry to the wire from the nozzle. A wire saw that presses and feeds a workpiece held by a device against a reciprocating wire and cuts the workpiece into a wafer shape,
The work feeding device has a work holding part, and holds the work through the contact plate and the work plate by the work holding part,
A wire saw characterized in that the maximum width of the lower end surface of the work holding portion is larger than the width of the work to be cut in a direction parallel to the wire row of the wire wound around the grooved roller. I will provide a.

  If it is such a wire saw, in the work holding part of the work feeding device that holds the work via the contact plate and the work plate, the maximum width of the lower end surface thereof is the wire row of the wire wound around the grooved roller. Since it is larger than the width of the workpiece to be cut in the parallel direction, it is possible to prevent the slurry scattered from the wire cut-in portion on the side surface of the workpiece from scattering to the side surface of the workpiece holding portion. Even if the workpiece is scattered on the side surface of the workpiece holding portion, the slurry splashed on the side surface of the workpiece holding portion flows down along the side surface of the workpiece holding portion as in the prior art, and the workpiece has already been cut into a wafer shape. It can prevent dripping at the part which became. Therefore, it is possible to suppress the occurrence of the bellows movement of the workpiece due to the dripping of the slurry onto the already cut workpiece, and as a result, it is effective to deteriorate the warp shape of the wafer, particularly in the latter half of the cutting. Therefore, it becomes possible to obtain a slice wafer having a good warp.

At this time, for example, the workpiece holding portion may be a clamper that holds the workpiece plate, and a lower end surface of the workpiece holding portion may be a lower surface of the clamper.
If this is the case, it is possible to prevent the slurry from splashing on the side surface of the clamper from the cut-in part of the wire on the side surface of the workpiece. It can prevent dripping at the location where it became. Therefore, it is possible to suppress the bellows movement of the workpiece and suppress the deterioration of the Warp shape.

  Alternatively, the workpiece holding unit includes a clamper that holds the workpiece plate, and a cover-like or block-like member that is disposed in contact with the clamper on both sides of the wire that cuts into and cuts out the workpiece. The lower end surface of the work holding part may be formed integrally with the lower surface of the clamper and the lower surface of the cover-like or block-like member.

  In this way, the lower end surface of the work holding portion is formed on the lower surface of the clamper and the lower surface of the cover-like or block-like member disposed in contact with the clamper on both the side where the wire cuts into the workpiece and the side where the wire is cut out. Since it is integrally formed, even if the maximum width of the lower surface of the clamper is smaller than the width of the workpiece, the slurry does not scatter to the side surface of the clamper, and the side surface of the cover-like or block-like member Can be prevented from being scattered. Therefore, from these side surfaces, it is possible to prevent the slurry from dripping onto a portion where the workpiece has already been cut and formed into a wafer shape, causing the bellows motion of the workpiece to deteriorate the Warp shape.

  Alternatively, the work holding unit includes a clamper for holding the work plate, and plate-like members disposed below the clamper and on both sides of the wire cutting and cutting sides. And the lower end surface of the said work holding | maintenance part shall be a lower surface of the said plate-shaped member.

  In this way, if the lower end surface of the workpiece holding portion is the lower surface of the plate-like member disposed below the clamper and on both sides of the wire cutting and cutting sides, It is possible to prevent the slurry from being scattered on the clamper and to prevent the slurry from being scattered on the side surface of the plate-like member. Therefore, from these side surfaces, it is possible to suppress the slurry from dripping onto a portion where the workpiece has already been cut and formed into a wafer shape, causing the bellows motion of the workpiece and deteriorating the Warp shape.

At this time, the lower end surface of the work holding part can be horizontal.
In this way, if the lower end surface of the work holding part is horizontal, it is possible to prevent the slurry from dripping intensively on a specific part of the work, in particular, a part of the work that has already been cut into a wafer shape. it can.

  Alternatively, the lower end surface of the workpiece holding portion has a taper that decreases toward the outside or the inside with respect to the workpiece to be cut in a direction parallel to the wire row of the wire wound around the grooved roller. It can be.

Slurry scattered to the lower end surface of the work holding part flows along the lower end surface having a taper and drops from the edge of the lower end surface.
At this time, if the lower end surface of the workpiece holding portion has a taper that decreases toward the outside with respect to the workpiece to be cut in a direction parallel to the wire row of the wire wound around the grooved roller, Since the maximum width of the lower end surface of the work holding part is larger than the width of the work to be cut, the slurry will drip further outward than the work, and the slurry will fall on the work from the edge of the lower end face of the work holding part. It can prevent dripping.
On the other hand, if the workpiece has a taper that decreases toward the inside with respect to the workpiece to be cut, the slurry scattered on the lower end surface of the workpiece holding portion can be reflected toward the outside of the workpiece, and the slurry is reflected on the workpiece. Can be prevented from dripping. In addition, the slurry attached to the lower end surface of the work holding part flows in the inner direction with respect to the work along the lower end surface, and even if the slurry drops on the work from the inner edge of the lower end surface, Since it is not a part of the workpiece that has already been cut into a wafer shape, but a block-like part before cutting, it is unlikely to cause a bellows movement, and it does not particularly adversely affect the warp of the wafer to be cut. .

  Further, the present invention corresponds to a contact plate that is wound on a plurality of grooved rollers and feeds slurry to the wire while traveling the wire in the axial direction, and is bonded to the workpiece to be cut. A workpiece cutting method for cutting and feeding a workpiece into a wafer shape by pushing down and holding a workpiece against a reciprocating wire while holding the workpiece through a workpiece plate holding a plate. The maximum width of the lower end surface of the workpiece holding portion is compared with the width of the workpiece to be cut when the workpiece holding portion and the workpiece plate are cut through the contact plate and the work plate. There is provided a workpiece cutting method characterized by cutting in a direction parallel to a wire row of wound wires so as to be larger than the width of the workpiece to be cut.

  With such a workpiece cutting method, when the workpiece to be cut is held and cut by the workpiece holding portion via the backing plate and the work plate, the workpiece holding portion is compared with the width of the workpiece to be cut. The maximum width of the lower end surface of the wire is cut so that it is larger than the width of the workpiece to be cut in the direction parallel to the wire row of the wire wound around the grooved roller. It is possible to prevent the slurry scattered from the part from splashing to the side of the work holding part, and even if it is scattered to the side of the work holding part, it flows down along the side of the work holding part and the work is already cut. It is possible to prevent the liquid from dropping on the wafer-like portion. For this reason, generation | occurrence | production of the bellows motion of a workpiece | work can be suppressed, the deterioration of the Warp shape of a wafer can be prevented effectively, and a slice wafer with favorable Warp can be obtained. Further, by comparing with the width of the workpiece to be cut, it is possible to cut the workpiece so that the maximum width of the lower end surface of the workpiece holding portion is larger than the width of the workpiece to be cut.

At this time, the workpiece holding portion can be constituted by a clamper that holds the workpiece plate, and a lower end surface of the workpiece holding portion can be a lower surface of the clamper.
In this way, it is possible to prevent the slurry from being scattered on the side surface of the clamper from the wire cut-in part on the side surface of the workpiece, and the slurry is already cut from the side surface of the clamper into a wafer shape. It is possible to prevent the liquid from dropping on the spot. Thereby, it is possible to suppress the bellows motion of the workpiece and suppress the deterioration of the Warp shape.

  Alternatively, the workpiece holding portion is formed by at least a clamper that holds the workpiece plate, and a cover-like or block-like member that is disposed in contact with the clamper on both sides of the wire cutting into and cutting out from the workpiece. The lower end surface of the work holding portion may be formed integrally with the lower surface of the clamper and the lower surface of the cover-like or block-like member.

  In this way, even if the maximum width of the lower surface of the clamper is smaller than the width of the workpiece, the slurry is not scattered on the side surface of the clamper, and is also scattered on the side surface of the cover-like or block-like member. Can be prevented. Therefore, from these side surfaces, it is possible to prevent the slurry from dripping onto a portion where the workpiece has already been cut and formed into a wafer shape, causing the bellows motion of the workpiece to deteriorate the Warp shape.

  Alternatively, the work holding unit is composed of at least a clamper that holds the work plate, and plate-like members disposed below the clamper and on both sides of the wire cutting and cutting sides. And the lower end surface of the said workpiece | work holding | maintenance part can be made into the lower surface of the said plate-shaped member.

  In this way, it is possible to prevent the slurry from splashing on the clamper, and also to prevent the slurry from splashing on the side surfaces of the plate-like member. From these side surfaces, the slurry is already cut into a wafer shape. It is possible to prevent the warp shape from deteriorating due to drooping on the spot and causing a work bellows motion.

And at this time, the lower end surface of the said work holding part can be made horizontal.
Thus, if the lower end surface of the work holding part is leveled, it is possible to prevent the slurry from dripping intensively on a specific part of the work, in particular, a part of the work that has already been cut into a wafer shape.

Alternatively, the lower end surface of the workpiece holding portion has a taper that decreases toward the outside or the inside with respect to the workpiece to be cut in a direction parallel to the wire row of the wire wound around the grooved roller. It can be.
Thus, if the workpiece to be cut has a taper that decreases toward the outside, the maximum width of the lower end surface of the workpiece holding portion is cut larger than the width of the workpiece to be cut. The slurry is dripped further outward than the work, and the slurry can be prevented from dripping onto the work from the edge of the lower end surface of the work holding part.
On the contrary, if it has a taper that becomes lower inward with respect to the workpiece to be cut, the slurry scattered on the lower end surface of the workpiece holding part can be reflected toward the outside of the workpiece, It is possible to suppress dripping of the slurry. In addition, the slurry attached to the lower end surface of the work holding part flows in the inner direction with respect to the work along the lower end surface, and even if the slurry is dropped on the work from the inner edge of the lower end surface, Since it is not a portion of the workpiece that has already been cut into a wafer shape, but a block-like portion before cutting, it is unlikely to cause a bellows movement, and it does not particularly adversely affect the warp of the wafer to be cut. .

The workpiece to be cut can have a width of 300 mm or more.
As described above, even if the workpiece to be cut is relatively large, the slurry is scattered on the side surface of the workpiece holding portion, or the slurry is moved from the side surface of the workpiece holding portion to the portion where the workpiece has already been cut and becomes a wafer shape. Can be prevented from dropping, and the occurrence of the bellows motion of the workpiece and the deterioration of the Warp shape can be suppressed.

At this time, the workpieces to be cut can be cut, and a wafer group having a Warp of less than 9 μm can be cut out in total.
As described above, according to the workpiece cutting method of the present invention, it is possible to cut out a group of wafers having a Warp of less than 9 μm in total, and to obtain a slice wafer having a good Warp.

With the wire saw and workpiece cutting method of the present invention, it is possible to prevent the slurry scattered from the wire cut-in portion of the workpiece during cutting from dripping onto the portion of the workpiece that has already been cut into a wafer shape. Further, it is possible to prevent the warp shape of the wafer to be cut from deteriorating due to the bellows movement of the workpiece caused by the dropped slurry, and to obtain a slice wafer having a good warp.

It is the schematic which shows an example of the wire saw of this invention. It is the schematic which shows an example of the workpiece feeding apparatus in the wire saw of this invention. It is the schematic which shows an example of the workpiece holding part in this invention. It is the schematic which shows another example of the workpiece holding part in this invention. (A) When a cover member is provided, (B) When a block member is provided. It is the schematic which shows another example of the workpiece holding part in this invention. It is the schematic which shows another example of the workpiece holding part in this invention. 6 is a graph showing measurement results of Warp for the total number of cut wafers in Example 1; 6 is a graph showing a measurement result of Warp for the total number of cut wafers in Comparative Example 1; It is a graph which shows the measurement result of Warp section shape in Example 1 and comparative example 1. It is the schematic which shows an example of the conventional wire saw. It is the schematic which shows an example of the workpiece feeding apparatus in the conventional wire saw. It is explanatory drawing which shows the mode of the flow of the slurry when the center part is cut | disconnected from the cutting start part of a workpiece | work using the conventional wire saw apparatus. It is explanatory drawing which shows the state into which the slurry flowed into the location cut by the wire. It is explanatory drawing which shows a mode that slurry disperses to the side surface of a workpiece holding part. It is explanatory drawing which shows a mode that slurry is dripped from the side surface of a workpiece | work holding | maintenance part to the location which has already been cut | disconnected and became wafer shape.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.
FIG. 1 is a schematic view showing an example of the wire saw of the present invention.
The wire saw 1 of the present invention shown in FIG. 1 has a configuration other than the workpiece feeding device 5 for feeding a workpiece to be cut to a lower wire, for example, a wire 2 for cutting the workpiece, and a groove around which the wire 2 is wound. The roller 3, the mechanism 4 for applying tension to the wire 2, the mechanism 6 (including the nozzle 17) for supplying slurry at the time of cutting are not particularly limited, and can be the same as the conventional one.

Next, FIG. 2 shows an example of a workpiece feeding device in the wire saw of the present invention.
The workpiece feeding device 5 includes a workpiece holding unit 11 for holding a workpiece, an LM guide 12 for feeding the workpiece downward, and a workpiece feeding main body unit 13, and the workpiece feeding along the LM guide 12 by computer control. By driving the main body 13, the work held by the work holding part 11 can be sent out at a feed speed programmed in advance.
The work is held by the work holding part 11 through the contact plate 14 and the work plate 15 as in the conventional case.

  Hereinafter, the workpiece holding unit 11 of the workpiece feeding device 5 will be described more specifically with a configuration example. However, if the maximum width of the lower end surface 11u facing the workpiece to be cut is greater than the width of the workpiece in the direction parallel to the wire row of the wire 2 wound around the grooved roller, the workpiece holding portion 11 Well, the wire saw 1 of the present invention is not limited to the following examples.

(When the work holding part is a clamper)
First, the case where the lower surface of the workpiece holding unit 11 is only a clamper that holds the workpiece by holding the workpiece plate 15 will be described with reference to FIG.
In this case, as shown in FIG. 3, as the clamper 16A, the maximum width of the lower surface 16Au (corresponding to the lower end surface 11u of the work holding portion 11 in FIG. 2) is larger than the width of the work in the direction parallel to the wire row. Prepare something bigger.

  In the case of a wire saw provided with a workpiece feeding device having such a wide clamper 16A, even when the slurry is scattered toward the upper side of the workpiece on the side surface of the workpiece when the workpiece is cut after the center portion of the workpiece, the clamper 16A It is possible to prevent scattering on the side surface 16As. As shown in FIG. 3, since the maximum width of the lower surface 16Au of the clamper 16A is larger than the width of the workpiece, the slurry does not scatter from the wire cut portion on the side surface of the workpiece to the side surface 16As of the clamper 16A.

Accordingly, in the present invention, as a matter of course, the slurry is scattered on the side surface 116s of the clamper 116 and flows down along the side surface 116s, as in the case of using a wire saw provided with the conventional work holding unit shown in FIGS. There is no possibility of dripping concentrated on the cut wafer-shaped part of the workpiece. In the present invention, even if the slurry is scattered on the side surface of the clamper, the maximum width of the clamper is larger than that of the workpiece, so that the slurry does not flow down concentrated on the cut portion of the workpiece.
Therefore, in the latter half of the cutting (particularly in the vicinity of the cutting end), the bellows movement of the workpiece caused by the dripping of the slurry onto the portion of the workpiece that has been cut in the wafer shape can be sufficiently suppressed compared to the conventional case. It becomes possible to remarkably suppress deterioration of the Warp shape of the wafer to be cut.

  Next, another example of the work holding unit will be described. Here, the case where the maximum width of the lower surface is smaller than the width of the workpiece will be described as an example, but the following example is a case where the maximum width of the lower surface is larger than the width of the workpiece. It is possible to apply.

(When the work holding part has a clamper and a cover or block-shaped member adjacent to the clamper)
As shown in FIG. 4A, when the maximum width of the lower surface 16Bu of the clamper 16B is smaller than the width of the workpiece, for example, on the both sides of the wire 2 cut into the workpiece and the cut-out side in contact with the clamper 16B. A cover-like member 20 is disposed. At this time, the lower surface 20u of the cover-like member 20 is disposed so as to have the same height as the lower surface 16Bu of the clamper 16B, so that the lower surfaces 20u and 16Bu are integrated.
That is, in this case, the work holding part 11 is configured by the clamper 16B and the cover-like member 20, and the lower surfaces 20u and 16Bu integrated with each other correspond to the lower end face 11u of the work holding part 11 (see FIG. 2). ).
The cover-like member 20 may have a size such that the combined width of the lower surface 20u and the lower surface 16Bu of the clamper 16B is larger than the width of the workpiece, and can be determined each time.

  Further, as shown in FIG. 4B, a block-like member 21 may be provided instead of the cover-like member 20. In this case, by arranging the lower surface 21u of the block-shaped member 21 so as to be the same height as the lower surface 16Bu of the clamper 16B, the lower surfaces 21u and 16Bu are integrated.

  As described above, in the case where cover-like members 20 and block-like members 21 having appropriate sizes are disposed on both sides of the clamper 16B, even if the maximum width of the lower surface 16Bu of the clamper 16B is smaller than the width of the workpiece, By combining the cover-like member 20 and the block-like member 21 on both sides, the lower end surface 11u having a maximum width larger than the workpiece width can be formed as a whole.

As can be seen from FIG. 4A (or FIG. 4B), the clamper 16B and the cover-like member 20 (or block-like member 21) are in contact with each other, so that naturally the slurry is scattered on the side face 16Bs of the clamper 16B. Never do.
Further, the maximum width of the surface (corresponding to the lower end surface 11u of the work holding portion 11) formed integrally with the lower surface 20u of the cover-like member 20 (or the lower surface 21u of the block-like member 21) and the lower surface 16Bu of the clamper 16B. Since it is larger than the width of the workpiece, it is possible to prevent the slurry from scattering to the side surface 20s of the cover-like member 20 (side surface 21s of the block-like member 21). For this reason, the slurry is prevented from dropping from the side surface 16Bs of the clamper or the side surface 20s of the cover-like member (the side surface 21s of the block-like member) to the cut portion of the work, and the bellows of the work generated by the dripping of the slurry. It is possible to remarkably suppress the warp shape of the wafer to be cut and even the cut.

(When the work holding part has a clamper and a plate-like member located below the clamper)
As still another example, as shown in FIG. 5, plate-like members 22 are disposed below the clamper 16B and on both sides of the wire 2 cutting and cutting sides. Can do.
That is, in this case, the workpiece holding portion 11 is configured by the clamper 16B and the plate-like member 22, and the lower surface 22u of the plate-like member 22 corresponds to the lower end surface 11u of the workpiece holding portion 11. In addition, what is necessary is just to have the largest width by the lower surface 22u of the plate-shaped member 22 larger than the width | variety of a workpiece | work, and a suitable thing can be prepared each time.

  And since the maximum width by the lower surface 22u of these plate-shaped members 22 is larger than the width | variety of a workpiece | work, it can prevent that a slurry scatters to the side surface 22s of the plate-shaped member 22, and the clamper 16B, Therefore It is possible to prevent the slurry from dripping from 22 s or the like to the cut part of the workpiece. As a result, it is possible to suppress the bellows movement of the workpiece and remarkably suppress the deterioration of the warp shape of the wafer to be cut.

  As described above, the configuration of the work holding unit 11 has been described with an example. In particular, the cover-like member 20, the block-like member 21, or the plate-like member 22 as shown in FIGS. As long as it includes a clamper that is smaller than the width of the existing workpiece, it is only necessary to attach each member of an appropriate size to the clamper or the like so as to form a lower end surface 11u that is larger than the width of the workpiece. It is convenient because it is good.

Here, the shape of the lower end surface 11u of the work holding part 11 will be described in more detail.
For example, as shown in FIGS. 3 and 4 (the lower surface 16Au of the clamper 16A is shown in FIG. 3, the lower surface 16Bu of the clamper 16B is integrated with the cover-like member 20 as shown in FIG. It corresponds to the lower surface 20u) and can be horizontal. At this time, even if the slurry scattered from the cut-in part on the side surface of the work reaches the lower end surface 11u of the work holding part and then drops, the specific part of the work, particularly the work has already been cut into a wafer shape. It is possible to prevent the slurry from dripping intensively at the location.

  Further, as shown in FIG. 5, the lower end surface 11 u of the workpiece holding portion 11 (corresponding to the lower surface 22 u of the plate-like member 22 in FIG. 5) is a workpiece to be cut in a direction parallel to the wire row of the wires 2. On the other hand, in the case of having a taper that decreases toward the outside, even if the slurry flows along the lower end surface 11u and drops from the edge, the maximum width of the lower end surface 11u of the workpiece holding portion 11 is larger than the width of the workpiece to be cut. Since the slurry is large, the slurry is dripped through the outside of the workpiece, and the slurry can be prevented from dripping onto the workpiece.

  On the other hand, as shown in FIG. 6, the lower end surface 11 u of the workpiece holding portion 11 (corresponding to the lower surface 22 ′ u of the plate-like member 22 ′ in FIG. 6) is parallel to the wire row of the wires 2. When the workpiece to be cut has a taper that decreases toward the inside, the scattered slurry can be reflected toward the outside of the workpiece, and the slurry attached to the lower end surface of the workpiece holding portion is Even if slurry flows on the workpiece along the lower end surface and flows inward from the edge of the lower end surface, it drops on the block-shaped part before cutting the workpiece, causing a bellows movement. The warp of the wafer to be cut is not particularly adversely affected.

  In addition, the taper angle of the lower end surface 11u of the workpiece holding part 11 in this case is not particularly limited, and can be appropriately determined according to, for example, the type of slurry to be used, the distance from the workpiece to be cut, and the like.

Next, the work cutting method of the present invention will be described.
In the workpiece cutting method according to the present invention, the maximum width of the lower end surface of the workpiece holding portion is reliably compared with the width of the workpiece once cut in the direction parallel to the wire row. The workpiece is cut so as to be larger than the above. Other than this, for example, the workpiece can be cut in the same procedure as in the prior art.

At this time, more specifically, as an example, as in the wire saw of the present invention in FIG. 3, the workpiece holding portion is formed of a clamper 16 </ b> A in which the maximum width of the lower surface 16 Au is larger than the width of the workpiece in the direction parallel to the wire row. The workpiece can be cut by configuring.
Moreover, like the wire saw of this invention of FIG. 4 (A) and FIG. 4 (B), a workpiece | work holding | maintenance part can be further comprised using the cover-shaped member 20 and the block-shaped member 21 other than the clamper 16B. .
Or like the wire saw of this invention like FIG. 5, FIG. 6, a workpiece | work holding | maintenance part can be comprised by arrange | positioning plate-shaped members 22 and 22 'further below the clamper 16B.
In any case, the workpiece is cut in a state where the maximum width of the lower end surface of the workpiece holding portion is larger than the width of the workpiece to be cut.

  The cover-like member 20 and the like may be disposed after the workpiece to be cut is held by the clamper, or may be previously disposed before being held by the clamper. It is only necessary that the maximum width of the lower end surface of the workpiece holding portion when cutting the workpiece is larger than the width of the workpiece to be cut.

  Also, the lower end surface of the work holding portion can be horizontal as shown in FIGS. 3, 4A, and 4B, for example, and the wire array as shown in FIGS. In the parallel direction, it may have a taper that decreases toward the outside or the inside with respect to the workpiece to be cut. About the angle of the lower end surface of such a workpiece | work holding | maintenance part, what is necessary is just to determine suitably according to other conditions etc. each time.

  The size of the workpiece to be cut is not particularly limited, but in particular, the workpiece width can be 300 mm or more. Even if it is such a relatively large one, if it is the present invention, it is possible to reliably prevent the scattered slurry from flowing down along the side surface of the work holding part and dropping onto the cut part of the work. As a result, a slice wafer with good Warp can be obtained.

In particular, a slice wafer group having a Warp of less than 9 μm can be obtained. Even if the slice wafer is cut from the end face side of the workpiece where Warp is likely to deteriorate, Warp can be suppressed to a relatively small value. For example, the total number of wafers can be cut with a good value of less than 9 μm. It is.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to this.
Example 1
As shown in FIG. 5, a silicon ingot having a diameter of 300 mm and an axial length of 180 mm is formed in a wafer shape by using the wire saw device of the present invention provided with a plate-like member having a taper that becomes lower toward the outside below the clamper. Cut to obtain 165 slice wafers.
In addition, with respect to the silicon ingot having a width (diameter) of 300 mm, the workpiece holding portion is composed of a clamper 16B having a width of 260 mm and a pair of plate-like members 22 having a width of 388 mm and larger than the width of the silicon ingot. I prepared something.

Using a wire with a diameter of 160 μm, applying a tension of 2.5 kgf, running the wire in a reciprocating direction at a cycle of 60 s / c at an average speed of 500 m / min, and supplying slurry from the nozzle toward the wire Then, the silicon ingot was pressed against the wire row by the work feeding device and cut to obtain a slice wafer.
Thus, the cutting method of the workpiece | work of this invention was implemented.

And the flow of slurry was observed during cutting.
From the start of cutting to the time of cutting the center part of the silicon ingot, it dropped from the cut part of the wire to the lower side of the silicon ingot.
On the other hand, when cutting from the central portion, the slurry was scattered from the cut portion of the wire to above the silicon ingot. At this time, most of the slurry scattered up to the lower surface 22u of the plate-like member flowed down along the lower surface 22u and dropped from the outer edge of the lower surface 22u. And the slurry dripped from the edge fell further downward without being applied on the silicon ingot being cut.
Further, since the plate-like member 22 is disposed below, the slurry does not scatter to the clamper 16B, and naturally the slurry does not drip from the side surface of the clamper 16B as in the prior art.

Further, when the silicon ingot was observed, the occurrence of bellows movement was significantly suppressed in the portion that was already cut and formed into a wafer shape during the cutting after the center portion of the silicon ingot, as compared with Comparative Example 1 described later. It was.
Here, FIG. 7 shows the measurement results of Warp for all the cut wafers. The average value of Warp is 4.67 μm, which is found to be suppressed to about 60% compared to the case where a conventional wire saw is used (Comparative Example 1: 7.72 μm). It can be seen that the wire saw of the present invention can suppress the size of the Warp of the slice wafer and can obtain an excellent quality product.

(Comparative Example 1)
A silicon ingot was cut into a wafer shape in the same manner as in the example except that a conventional wire saw having a work feeding device as shown in FIG. 11 was used.
In the wire saw used here, the work holding part was composed only of a clamper, and its width was 260 mm, which was smaller than the width of the silicon ingot.

  When the inventor observed the flow of the slurry during cutting, unlike Example 1, the slurry was scattered to the side surface of the clamper having a width smaller than that of the silicon ingot while cutting the center portion of the silicon ingot. At first, the slurries that had splattered then flowed down along the sides of the clamper. As the cutting further progressed, the slurry from the side surface of the clamper was dripped onto the already cut and wafer-like portion.

Further, when observing the silicon ingot, bellows motion frequently occurred at the location where the silicon ingot was cut into a wafer shape.
Here, FIG. 8 shows the measurement results of Warp for all the cut wafers. The average value of Warp was 7.72 μm, which was a large value.

  In each of Example 1 and Comparative Example 1, the silicon ingot was cut into a wafer shape, and from each of the cut wafers, the first wafer was extracted from the new line supply side, and the Warp shape was measured. The measurement results are shown in FIG.

As shown in FIG. 9, in Example 1 in which cutting was performed using the wire saw of the present invention and Comparative Example 1 in which cutting was performed using a conventional wire saw, in particular, in the vicinity of the end of cutting (from a cutting position of 270 mm) 300 mm), a large difference is seen in the Warp shape.
In Comparative Example 1, the slurry scattered to the side surface of the clamper is concentrated and dripped from a specific portion of the silicon ingot (a portion cut in a wafer shape), thereby causing an accordion movement. The Warp shape is thought to have deteriorated.

On the other hand, in Example 1, although slurry is scattered on the lower surface of the plate-like member 22 disposed below the clamper, most of the scattered slurry is dropped from the edge of the lower surface of the plate-like member wider than the ingot. In addition, it was possible to suppress the occurrence of the bellows movement without being applied to the portion of the silicon ingot cut into a wafer shape. And it was possible to remarkably suppress deterioration of the Warp shape.

(Example 2)
Using the wire saw apparatus of the present invention as shown in FIG. 3, a silicon ingot having a diameter of 300 mm and an axial length of 180 mm is cut into a wafer shape to obtain 165 slice wafers.
In addition, with respect to the silicon ingot having a width (diameter) of 300 mm, a workpiece holding unit including a clamper 16A having a width of 360 mm was prepared.
Other cutting conditions were the same as in Example 1.
Thus, the cutting method of the workpiece | work of this invention was implemented.

Since a clamper wider than the silicon ingot to be cut was used, the slurry scattered from the wire incision part of the silicon ingot did not reach the side surface of the clamper, and the slurry dropped on the side surface of the clamper as before. It never happened.
The occurrence of bellows movement was also suppressed, and the Warp value of the cut wafer was as small as in Example 1, and an excellent quality slice wafer could be obtained.

(Example 3)
Using a wire saw device of the present invention as shown in FIG. 4A, a silicon ingot having a diameter of 300 mm and an axial length of 180 mm is cut into a wafer shape to obtain 165 slice wafers.
In addition, for the silicon ingot having a width of 300 mm, a workpiece holding unit including a clamper 16B having a width of 260 mm and two cover members 20 each having a width of 100 mm was prepared. The positions in the height direction of the lower surface 16Bu of the clamper 16B and the lower surface 20u of the cover member 20 were made to coincide with each other, and the cover member 20 was disposed in contact with both sides of the clamper 16B. The width of the surface formed integrally as described above was 460 mm.
Thus, the cutting method of the workpiece | work of this invention was implemented.

Since the above-mentioned integrally formed surface facing the silicon ingot to be cut is wider than the silicon ingot, the slurry scattered from the cut portion of the wire of the silicon ingot is the side surface of the cover member 20 on both sides. 20s was not reached, and the slurry did not drip along the side surface.
The occurrence of bellows movement was also suppressed, and the Warp value of the cut wafer was as small as in Example 1, and an excellent quality slice wafer could be obtained.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has the same configuration as the technical idea described in the claims of the present invention. It is included in the technical scope of the invention.

  For example, in the embodiment, a workpiece having a width of 300 mm is used, but the present invention is not limited to this, and can be applied to a workpiece having a width of more than 300 mm, for example, 400 mm or more. According to the present invention, it is possible to obtain a slice wafer group having a good warp (for example, less than 9 μm) even for such a workpiece having a larger width.

Claims (14)

At least a wire that is wound around a plurality of grooved rollers and reciprocates in the axial direction, a nozzle that supplies slurry to the wire, a contact plate that is bonded to the workpiece to be cut, and a workpiece that holds the corresponding plate A wire feed device that includes a workpiece feeding device that pushes down and feeds the wire to the wire while holding the workpiece through the plate, and that reciprocates the workpiece held by the workpiece feeding device while supplying slurry to the wire from the nozzle. A wire saw that presses against and feeds and cuts the workpiece into a wafer shape,
The work feeding device has a work holding part, and holds the work through the contact plate and the work plate by the work holding part,
A wire saw characterized in that the maximum width of the lower end surface of the work holding portion is larger than the width of the work to be cut in a direction parallel to the wire row of the wire wound around the grooved roller. .
The work holding unit is a clamper that holds the work plate,
The wire saw according to claim 1, wherein a lower end surface of the work holding portion is a lower surface of the clamper.
The workpiece holding portion includes a clamper that holds the workpiece plate, and a cover-like or block-like member that is disposed in contact with the clamper on both sides where the wire cuts into and cuts out from the workpiece. Yes,
2. The wire saw according to claim 1, wherein a lower end surface of the work holding portion is formed by integrating a lower surface of the clamper and a lower surface of the cover-like or block-like member.
The work holding unit includes a clamper that holds the work plate, and plate-like members disposed below the clamper and on both sides of the wire cutting and cutting sides. ,
The wire saw according to claim 1, wherein a lower end surface of the work holding portion is a lower surface of the plate-like member.
The wire saw according to any one of claims 1 to 4, wherein a lower end surface of the work holding portion is horizontal.
The lower end surface of the workpiece holding portion has a taper that decreases toward the outside or the inside with respect to the workpiece to be cut in a direction parallel to the wire row of the wire wound around the grooved roller. The wire saw according to any one of claims 1 to 4, wherein the wire saw is provided.
A work plate that winds a wire around a plurality of grooved rollers and feeds slurry to the wire while running the wire in the axial direction, and a work plate that holds the plate corresponding to the work piece bonded to the work to be cut The workpiece is cut and fed to the wire that is pushed down while holding the workpiece and reciprocating, and cut into a wafer shape.
When the workpiece to be cut is held and cut by the workpiece holding unit via the backing plate and the workpiece plate,
Compared with the width of the workpiece to be cut, the maximum width of the lower end surface of the workpiece holding portion is larger than the width of the workpiece to be cut in a direction parallel to the wire row of the wire wound around the grooved roller. A method for cutting a workpiece, wherein the workpiece is cut in a large size.
The work holding part is constituted by a clamper that holds the work plate,
The work cutting method according to claim 7, wherein a lower end surface of the work holding portion is a lower surface of the clamper.
The workpiece holding unit is configured by at least a clamper that holds the workpiece plate, and a cover-like or block-like member that is disposed on both sides of the wire-cutting side and the cutting-out side in contact with the clamper. ,
8. The workpiece cutting according to claim 7, wherein the lower end surface of the workpiece holding portion is formed integrally with the lower surface of the clamper and the lower surface of the cover-like or block-like member. Method.
The work holding part is constituted by at least a clamper that holds the work plate, and plate-like members disposed below the clamper and on both sides of the wire cutting and cutting sides.
The work cutting method according to claim 7, wherein a lower end surface of the work holding portion is a lower surface of the plate-like member.
The work cutting method according to any one of claims 7 to 10, wherein a lower end surface of the work holding portion is made horizontal.
The lower end surface of the workpiece holding portion has a taper that decreases toward the outside or the inside with respect to the workpiece to be cut in a direction parallel to the wire row of the wire wound around the grooved roller. The workpiece cutting method according to any one of claims 7 to 10, wherein the workpiece is cut.
The workpiece cutting method according to any one of claims 7 to 12, wherein the workpiece to be cut has a width of 300 mm or more.
  14. The work cutting method according to claim 7, wherein the work to be cut is cut, and a wafer group having a Warp of less than 9 μm is cut out in total.

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