JP2021070115A - Wire removal method - Google Patents

Abstract

To suppress a wire from being caught to prevent a wafer from being broken and scratched, in removing the wire from a cut monocrystal.SOLUTION: A wire removal method is a method for cutting a monocrystal held on a pedestal into a plurality of wafers using a wire of a wire-saw device and then removing the wire from the plurality of wafers, which includes the steps of: supplying the wafers with predetermined liquid; and moving the pedestal in an opposite direction of a cutting direction of the monocrystal relatively with respect to the wire.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wire removing method in a wire saw device.

It is known that a single crystal is cut by a multi-wire saw device (wire saw device) to form a plurality of wafers. For example, in the cutting method using the wire saw device described in Patent Document 1, three (or two) spindle rollers are provided, and grooves are formed on the outer periphery of the spindle rollers at a pitch matching the target wafer thickness. A wire saw device is used in which a single wire is wound along a groove of a spindle roller. Then, the spindle roller is rotated to run the wire, and the main body table to which the single crystal is fixed is operated to press the single crystal against the wire to cut the single crystal into a large number of wafers.

The detailed procedure is to fix the single crystal to the slice base of the wire saw device via the pedestal. The single crystal is held on the pedestal by an adhesive. After that, the slicing table is installed in the wire saw device. Next, processing is started with a wire saw device, the slicing table moves to the processing portion, and a single crystal is cut with a wire. In the cutting process, the pedestal is cut to about 5 mm with a wire. The thickness of the cut wafer is about 0.2 to 2.0 mm, and the end face portion is held on the pedestal only with an adhesive. In the cutting process using a wire, the workpiece is pressed against a plurality of ultrafine wire rows parallel to each other at a constant pitch, and while the wire is fed in the linear direction, abrasive grains are included between the workpiece and the wire. A free abrasive grain method that cuts by supplying a liquid (also called a slurry), and a fixed abrasive grain method that cuts a work piece while sending a wire in which abrasive grains such as diamond are fixed by electrodeposition or adhesive in the linear direction. There is.

Japanese Unexamined Patent Publication No. 2001-001248

When cutting from a single crystal to a wafer using the above-mentioned wire saw device, in order to surely cut the single crystal, even a part of the pedestal between the single crystal and the slicing table is cut as described above. After the cutting process is completed, it is necessary to remove the wire from the multiple wafers that have been cut. Generally, the slicing table is pressed from the position where the single crystal has been cut in the processing direction (the direction in which the single crystal is pressed against the wire). ) Is moved in the opposite direction to remove the wire sandwiched between the wafers. At this time, there is no particular problem when the single crystal diameter is small and the wafer thickness is thick. However, when the single crystal diameter is large and the thickness of the wafer is thin, when the wire is removed, a part of the wire sandwiched between the wafers may be caught on the side surface of the wafer and the wire may be stretched. If the slicing table is moved in this state, the wafer may be damaged by the wire. In order to improve this, for example, the work of pulling out the wire while feeding the wire at a low speed is performed. Even in this case, the phenomenon that a part of the wire is caught on the side surface of the wafer may occur. Further, at this time, the wafer may have scratches on the wire at the position where the wire is caught.

The present invention provides a wire removing method capable of suppressing the catching of the wire and preventing the wafer from being damaged or scratched when the wire is removed from the single crystal after cutting by using a wire saw device. With the goal.

According to the first aspect of the present invention, a single crystal held on a pedestal is cut into a plurality of wafers using a wire of a wire saw device, and then the wire is removed from the plurality of wafers. A wire removal method is provided that comprises supplying a predetermined liquid and moving the pedestal relative to the wire in a direction opposite to the direction in which the single crystal is cut.

According to the second aspect of the present invention, there is provided a wire removing method in which the predetermined liquid is a processing liquid supplied at the time of cutting a single crystal in the first aspect.

According to a third aspect of the present invention, in the first or second aspect, a wire removing method is provided in which a predetermined liquid is supplied to a wafer via a backing plate.

According to a fourth aspect of the present invention, in the third aspect, the receiving plate is placed on a wire or the receiving plate is supported by a support member prior to the supply of a predetermined liquid. A wire removal method is provided.

According to the fifth aspect of the present invention, in the third or fourth aspect, the backing plate is arranged so as to be inclined so that the predetermined liquid is directed toward the wafer, or the predetermined liquid is directed toward the wafer. A wire removal method is provided that has an inclined surface.

According to a sixth aspect of the present invention, in any one of the third to fifth aspects, the backing plate is a wire having a side wall at an edge in a direction intersecting a direction of supplying a predetermined liquid. A removal method is provided.

According to the above-described aspect of the present invention, in the work of cutting a single crystal into a plurality of wafers using a wire saw device and then removing the wire from the plurality of cut wafers, the wire is suppressed from being caught in the wafer. , Wafer damage and scratches can be prevented.

It is a flowchart which shows an example of the wire removal method which concerns on embodiment. It is a figure which shows an example of a wire saw device. The operation of cutting a single crystal with a wire saw device is shown, (A) is a perspective portion before cutting, and (B) is a perspective view after cutting. It is a perspective view which shows the state which supplies the liquid to a plurality of wafers. It is a figure which looked at the state of a plurality of wafers after a cutting process from the Y direction. It is a perspective view which shows the state in the process of removing a wire from a plurality of wafers. It is a figure which looked at the state of the wafer in the process of removing a wire from the Y direction. Another example of the receiving plate is shown, (A) is a view of a state in which the receiving plate is arranged in an inclined manner, and (B) is a view of a receiving plate provided with an inclined surface. It is a perspective view which shows the other example of a receiving plate. It is a figure which shows another example of a receiving plate. It is a figure which shows another example of a wire saw device.

Hereinafter, embodiments will be described with reference to the drawings. In the drawings, in order to make each configuration easy to understand, a part may be emphasized or simplified, and the structure, shape, scale, etc. in the actual product may be different. Further, in the drawings, each direction is shown using an XYZ Cartesian coordinate system. In this XYZ Cartesian coordinate system, the X direction and the Y direction are horizontal directions, and the Z direction is a vertical direction perpendicular to the X direction and the Y direction. Further, in each direction, the side pointed by the arrow is referred to as a + side (eg, + Z side), and the opposite side is referred to as a − side (eg, −Z side). For example, in the vertical direction (Z direction), the upper side is the + Z side and the lower side is the −Z side.

FIG. 1 is a flowchart showing an example of a wire removing method according to an embodiment. As shown in FIG. 1, the wire removing method includes a cutting step (step S1), a liquid supply step (step S2), and a wire removing step (step S3). In the embodiment, the “wafer” means a disk-shaped plate formed by cutting a columnar single crystal (ingot). The wire removing method according to the present embodiment is executed by using the wire saw device 1. First, the wire saw device 1 will be described. FIG. 2 is a diagram showing an example of a wire saw device.

The wire saw device 1 shown in FIG. 2 is a so-called multi-wire saw device. The wire saw device 1 includes rotary rollers 2a, 2b, 2c, a wire 3, a slice base 6, a pedestal 7, a mounting portion 8, and a liquid supply portion 9. In the wire saw device 1, a plurality of slice bases 6 to which a single crystal C is fixed are mounted on a mounting portion 8, and the mounting portions 8 are stretched between three sets of rotating rollers 2a to 2c at predetermined intervals. While moving the single crystal C relative to the wire row 4 composed of the wires 3 and pressing the single crystal C in the cutting direction (Z direction in the figure), each wire 3 (wire row 4) is moved in one direction or in the reciprocating direction. The single crystal C is cut. By cutting the single crystal C using such a wire saw device 1, a large number of wafers W can be formed from the single crystal C by one cutting, so that a plurality of wafers W can be efficiently obtained from the single crystal C. be able to.

The single crystal C is fixed to the slice base 6 via the pedestal 7 (slice bed). The pedestal 7 has a plate shape, and both the upper surface and the lower surface are formed along a horizontal plane. A single crystal C is fixed to the lower surface of one of the pedestals 7 which is a horizontal plane. The single crystal C is held on the lower surface of the pedestal 7 by a part of the circumferential surface Sc being adhered to the pedestal 7 by the adhesive 10. The other horizontal upper surface of the pedestal 7 is fixed to the slice pedestal 6.

The slice base 6 is mounted on the mounting portion 8 of the wire saw device 1. The mounting portion 8 can adjust the position and angle of the mounted slice base 6, and the single crystal C can be positioned by this adjustment. The slicing table 6 is a removable type in the wire saw device 1, and by attaching or detaching the slicing table 6 to the wire saw device 1, the single crystal C in the wire saw device 1 is fixed or cut. W can be removed.

In the cutting step of step S1 shown in FIG. 1, the single crystal C held on the pedestal is cut by the wire saw device 1 to obtain a plurality of wafers W. In the cutting step of step S1, a fixed abrasive grain method in which a wire 3 to which abrasive grains are fixed in advance is used to supply a processing liquid L for cooling a portion where the wire 3 and the single crystal C come into contact with each other, and an abrasive grain. Any of the free abrasive grain method in which the processing liquid L containing the abrasive grains is supplied to the portion where the wire 3 and the single crystal C come into contact with each other by using the wire 3 to which the wire 3 is not fixed may be used. The processing liquid L used in the free abrasive grain method also has an action of cooling the portion where the wire 3 and the single crystal C come into contact with each other.

The processing liquid L is discharged from the nozzle 91 to the portion where the wire 3 and the single crystal C come into contact with each other. The nozzles 91 are arranged at two locations on both sides of the single crystal C in the traveling direction of the wire 3. Each of the two nozzles 91 discharges the machining fluid L diagonally downward. In the present embodiment, two nozzles 91 are arranged, but any one of them may be arranged, or two or more nozzles 91 may be arranged. The shape of the tip of the nozzle is not particularly limited. For example, the tip of the nozzle may be formed in a shape in which a plurality of small-diameter holes are formed and discharged in a shower shape, or in an elongated slit shape so as to be arranged in the entire single crystal. The liquid supply unit 9 sends the processing liquid L stored in a tank or the like (not shown) to the nozzle 91. The liquid supply unit 9 includes, for example, a pump for sending liquid, a flow meter, and the like.

Next, the cutting step of step S1 will be described with reference to FIG. 3A and 3B show an operation of cutting a single crystal with a wire saw device, FIG. 3A is a perspective view before cutting, and FIG. 3B is a perspective view after cutting. First, prior to the cutting step, the single crystal C is fixed at a predetermined position of the wire saw device 1. The single crystal C is fixed in the order of, for example, bonding the single crystal C to the pedestal 7, fixing the pedestal 7 to the slice base 6, and mounting the slice base 6 to the mounting portion 8.

Adhesion of the single crystal C to the pedestal 7 is performed, for example, by applying an adhesive 10 to the pedestal 7 and pressing a part of the circumferential surface Sc of the single crystal C against the adhesive 10. The adhesive 10 is not particularly limited, but an epoxy adhesive is preferable so that the single crystal C does not come off from the pedestal 7 in the cutting step and the wafer W can be easily peeled off from the pedestal 7 after the cutting step. Further, when adhering the pedestal 7 and the single crystal C, an orientation flat (orifura) or a notch formed on a part of the circumferential surface Sc of the single crystal C may be directed to the pedestal 7. The pedestal 7 is fixed to the slice base 6 and the slice base 6 is attached to the mounting portion 8 by, for example, screwing. As described above, the cutting step of step S1 may include an bonding step of adhering a part of the circumferential surface Sc of the single crystal C to the pedestal 7 with the adhesive 10.

3A and 3B show an operation of cutting a single crystal C with a wire saw device 1, FIG. 3A is a perspective view before cutting, and FIG. 3B is a perspective view after cutting. As shown in FIG. 3A, the single crystal C is arranged above (+ Z side) of the wire row 4 in which a plurality of wires 3 are arranged at predetermined intervals (pitch) in the wire saw device 1. .. The wires 3 are stretched between the three sets of rotary rollers 2a to 2c at predetermined intervals to form a wire row 4 (see FIG. 2). Further, the wire 3 travels in one direction or a reciprocating direction by rotationally driving at least one of the rotary rollers 2a to 2c.

In the cutting step of step S1, as shown in FIG. 3A, the single crystal C is cut in the cutting direction with the plurality of wires 3 traveling in the Y direction and the nozzle 91 discharging the machining fluid L. It is moved downward (-Z direction) and pressed against the wire row 4. The single crystal C is cut by a plurality of wires 3, and as shown in FIG. 3B, a plurality of wafers W that are adhered to the pedestal 7 and are arranged in the X direction at intervals are formed.

After cutting the single crystal C, as shown in FIG. 3B, a part (lower surface) of the pedestal 7 is cut to a depth of about 5 mm. Therefore, the pedestal 7 is preferably made of a resin or glass that can be cut by the wire 3 and has a thickness of about 10 mm to 20 mm. By cutting a part of the pedestal 7, the single crystal C can be surely cut. The thickness of the wafer W (in the X direction) is not particularly limited, but is set to, for example, 0.2 mm to 1.0 mm. The thickness of the wafer W and the spacing between the wafers W can be set to a desired thickness and spacing by adjusting the diameter, spacing, and the like of the wires 3, respectively.

After the cutting step of step S1, the liquid supply step of step S2 is executed. In the liquid supply step of step S2, the processing liquid L is supplied to the contact portion between the wire 3 and the wafer W. FIG. 4 is a perspective view showing a state in which a processing liquid L, which is a liquid, is supplied to a plurality of wafers W. In the liquid supply process, the wire 3 running in the cutting process is stopped, and the discharge of the processing liquid L is stopped. Subsequently, the receiving plates X1 are placed on both sides of the wafer W on the wire row 4.

As the receiving plate X1, as shown in FIG. 4, a rectangular plate-like body is used. The weight of the receiving plate X1 is not particularly limited, but it is preferable that the weight of the receiving plate X1 is light so that the wire 3 does not bend so much when placed on the wire row 4. The receiving plate X1 is made of wood, resin, or metal, and for example, plastic (polyproethylene, polypropylene, etc.) can be used. The thickness of the receiving plate X1 is not particularly limited and can be appropriately set in consideration of the material and the like, and is preferably about 0.3 mm to 1.0 mm, for example.

Each of the receiving plates X1 is arranged below the nozzle 91. As a result, the machining fluid L discharged from the nozzle 91 flows on the receiving plate X1 and is sent toward the wafer W. That is, the receiving plate X1 prevents the processing liquid L from flowing down from between the wires 3 and efficiently supplies the processing liquid L to each wafer W. In the present embodiment, the receiving plate X1 is placed on the wire row 4 in the liquid supply step of step S2, but the present embodiment is not limited to this embodiment. For example, the liquid supply step in step S2 may be in the form of discharging the processing liquid L from the nozzle 91 toward the wafer W without using the receiving plate X1.

The position on which the receiving plate X1 is placed is not particularly limited as long as the processing liquid L can be supplied to each wafer W. For example, the receiving plate X1 is located at a position where the distance from the wafer W is 3 cm to 6 cm in the direction parallel to the wire 3 direction (Y direction) so that the processing liquid L can be efficiently supplied to each wafer W. May be set as. By moving the slicing table 6 (see FIG. 2), the wafer W and the receiving plate X1 may be appropriately adjusted so as to have an appropriate positional relationship. Further, the position where the receiving plate X1 is placed is set so that a plurality of wafers W can pass between the two receiving plates X1 in the direction perpendicular to the wire 3 direction (Z direction).

The machining fluid L may be supplied at the same flow rate as the machining fluid L used in the cutting step of step S1. For example, the processing liquid L is preferably supplied at 10 (l / min) to 50 (l / min) in the liquid supply step of step S2. The supply amount of the processing liquid L may be different from the cutting step of step S1. For example, if the supply amount of the processing liquid L can be adjusted, the supply amount may be smaller than that of the cutting step of step S1. ..

Next, the processing liquid L will be described. As described above, the predetermined liquid used in the liquid supply step of step S2 is the processing liquid L used in the cutting step of step S1. When the free abrasive grain method is used for the cutting step, a slurry in which abrasive grains are mixed with an oil-based processing liquid is used as the processing liquid L. In recent years, in the case of oil-based processing liquids, water-soluble slurries containing amine-based or glycol-based components have been used due to problems such as recycling after use and waste liquid treatment, and concerns about flammability. When the fixed abrasive grain method is used for the cutting step, a water-soluble processing liquid L is used as the processing liquid L. The processing liquid L may contain a glycol-based component for the purpose of improving affinity (surfactant activity) and permeability. The pH of the water-soluble processing liquid L is generally set to the alkaline side for rust resistance and the like, and is set to, for example, 8 to 10 pH.

In the liquid supply step of step S2, since the processing liquid L used in the cutting step of step S1 is used, it is possible to save the trouble of exchanging with another liquid, so that it is possible to prevent the work efficiency from being lowered. In this embodiment, the processing liquid L is used in the liquid supply step of step S2, but the present invention is not limited to this embodiment. For example, a liquid other than the processing liquid L may be used in the liquid supply step of step S2. For example, water, alcohol, or the like may be used instead of the processing liquid L.

By the liquid supply step of step S2, the processing liquid L is supplied between the plurality of wafers W. After the cutting step of step S1, the machining fluid L used in the cutting step remains, and the wafers W are stuck to each other due to the surface tension of the machining fluid L. FIG. 5 is a view of the state of the plurality of wafers W after the cutting step as viewed from the Y direction. As shown in FIG. 5, each wafer W is held on the pedestal 7 via the adhesive 10 at the upper part. The processing liquid L used in the cutting step remains after the cutting process and moves downward. As a result, as shown in FIG. 5, a phenomenon occurs in which a plurality of wafers W are overlapped with each other in the lower portion due to the surface tension of the processing liquid L. There is no particular problem when the crystal diameter is small and the thickness of the wafer W is thick, but when the single crystal diameter is large and the thickness of the wafer W is thin, the phenomenon shown in FIG. 5 is likely to occur.

When the wafer W is moved upward from the state shown in FIG. 5 to remove the wire 3, there arises a problem that the wire 3 is caught on the side surface of the wafer W and the wire 3 is stretched. At this time, in order to pull out the wire 3 downward, it is necessary to manually peel off the overlapping portions of the wafers W one by one, which is troublesome. Further, if the wire 3 is forcibly pulled downward, the side surface of the caught wafer W will be damaged. Further, a method of pulling out the wire 3 downward while feeding the wire 3 at a low speed is also conceivable, but a phenomenon that a part of the wire 3 damages the side surface of the wafer W occurs.

In the present embodiment, the processing liquid L is supplied between the plurality of wafers W by the liquid supply step of step S2 described above to reduce the surface tension for sticking the wafers W to each other, and the wire removal step of step S3 described later. In the above, when the wire 3 is pulled downward, the wire 3 is prevented from being caught on the side surface of the wafer W.

In the wire removing step of step S3, while supplying the processing liquid L to the wafer W, the plurality of wafers W are moved upward with respect to the wire 3 (in the direction opposite to the direction in which the single crystal C is cut). In the wire removing step of step S3, the processing liquid L may be continuously supplied or intermittently at regular time intervals.

FIG. 6 is a perspective view showing a state in which the wire 3 is being removed from the plurality of wafers W. FIG. 7 is a view of the state of the wafer W during the removal of the wire 3 as viewed from the Y direction. In the wire removing step, the processing liquid L is supplied to the wafer W to reduce the surface tension for sticking the wafers W to each other, and the wire 3 moves downward to stick (overlap) the wafer W. The lower parts of the are separated from each other (see FIG. 7). Further, the supplied processing liquid L acts as a lubricant between the wire 3 and the wafer W to prevent the side surface of the wafer W from being scratched. Further, when the surfactant is added to the processing liquid L, the effect of reducing the surface tension is enhanced, and the lower parts of the wafer W can be easily separated from each other.

By further moving the wafer W (pedestal 7) upward from the state shown in FIG. 7, the wire 3 is removed from the plurality of wafers W. The processing liquid L (see FIG. 7) accumulated in the vicinity of the wire 3 flows downward as the wire 3 moves downward, and a part or all of the processing liquid L is removed from the wafer W.

As described above, according to the present embodiment, while supplying the processing liquid L to the wafer W via the receiving plate X1, the pedestal 7 holding the wafer W is directed to the wire 3 at the time of cutting the single crystal C. By moving the wire 3 relative to the wafer W, the wire 3 can be removed from the wafer W without being caught by the wafer W and without scratching the wafer W. In the present embodiment, the configuration in which the single crystal C (wafer W) is moved in the vertical direction with respect to the wire 3 is described as an example, but the configuration is not limited to this configuration. For example, the wire 3 may be moved in the vertical direction with respect to the single crystal C (wafer W), or both the wire 3 and the single crystal C (wafer W) may be moved in the vertical direction. May be good.

In the above-described embodiment, the flat plate-shaped receiving plate X1 is used, but the receiving plate X1 may be in another form. FIG. 8 shows another example of the receiving plate, FIG. 8 (A) shows a state in which the receiving plate X2 is inclined by the support portion X2a, and FIG. 8 (B) shows the receiving plate provided with the inclined surface X3a. It is a figure of X3. As shown in FIG. 8A, the flat plate-shaped receiving plate X2 is arranged so as to be inclined so that the processing liquid L faces the wafer W. The receiving plate X2 is provided with a support portion X2a on the lower surface of the end portion on the side opposite to the wafer W side. The receiving plate X2 is placed on the wire 3 in a state of being supported by the end portion on the wafer W side and the supporting portion X2a. The processing liquid L discharged onto the receiving plate X2 becomes a flow toward the wafer W due to the inclination of the receiving plate X2. That is, the machining fluid L can be efficiently supplied to the wafer W as compared with the receiving plate X1 which is placed on the wire 3.

The receiving plate X3 shown in FIG. 8B includes an inclined surface X3a with the end portion of the wafer W on the lower side. The machining fluid L discharged onto the receiving plate X3 flows toward the wafer W due to the inclination of the inclined surface X3a. That is, similarly to the receiving plate X2 shown in FIG. 8A, the machining fluid L can be efficiently supplied to the wafer W as compared with the receiving plate X1 mounted on the wire 3.

FIG. 9 is a perspective view showing another example of the receiving plate. As shown in FIG. 9, the receiving plate X4 is arranged so as to be inclined so that the machining fluid L faces the wafer W, and both side edges in a direction (X direction) intersecting the direction in which the machining fluid L is supplied. X4a has a side wall X4b. The description of the support portion (corresponding to the support portion X2a in FIG. 8A) for inclining the receiving plate X4 is omitted. The processing liquid L discharged onto the receiving plate X4 becomes a flow toward the wafer W due to the inclination. Further, since the receiving plate X4 has the side wall X4b, it is possible to prevent the processing liquid L from falling from the receiving plate X4 in the direction intersecting the direction of the wire 3, and the processing liquid L can be reliably supplied to the wafer W. .. The side wall X4b shown in FIG. 9 can also be applied to the receiving plate X1 shown in FIG. 4 and the receiving plate X3 shown in FIG. 8 (B).

In the above-described embodiment, an example in which the receiving plates X1 to X4 are placed on the wire 3 is shown, but the present invention is not limited to this embodiment. The backing plate does not have to be placed on the wire 3. FIG. 10 is a diagram showing another example of the receiving plate. Note that FIG. 10 shows the + Y side of the wafer W, and the same configuration is applied to the −Y side of the wafer W. As shown in FIG. 10, the receiving plate X5 is supported by the support member T above the wire 3. The support member T may be fixed to a part of the wire saw device 1 or may be fixed to a place other than the wire saw device 1. The receiving plate X5 may be detachable from the support member T. Further, the receiving plate X5 may be attached to the support member T in a state of being inclined so that the end portion on the wafer W side is a low portion.

In the above-described embodiment, as the wire saw device 1, a configuration in which the wire 3 (wire row 4) is arranged on the lower side and the single crystal C is arranged on the upper side is described as an example, but the present embodiment is limited to this embodiment. Not done. FIG. 11 is a diagram showing another example of the wire saw device. In FIG. 11, the same components as those of the wire saw device 1 shown in FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted or simplified. As shown in FIG. 11, in the wire saw device 100, the single crystal C is arranged on the lower side, and the wire 3 (wire row 4) is arranged on the upper side. That is, the pedestal 7 that holds the single crystal C via the adhesive 10, the slicing pedestal 6 that fixes the pedestal 7, and the mounting portion 8 that mounts the slicing pedestal are arranged on the lower side, and the wire 3 is wound around the rotation. Rollers 2a to 2c are arranged on the upper side.

The two nozzles 91 are arranged at the respective positions sandwiching the single crystal C, discharge the processing liquid L diagonally upward, and supply the processing liquid L to the portion where the wire 3 and the single crystal C come into contact with each other. .. In FIG. 11, the description of the liquid supply unit 9 is omitted.

In the wire saw device 100 as well, the wire removing method according to the embodiment can be carried out in the same manner as in the wire saw device 1 described above. In the cutting step (step S1), the single crystal C is moved upward, or the wire row 4 is moved downward, and the traveling wire 3 is pressed against the single crystal C to form a plurality of wafers W. In the liquid supply step (step S2), the processing liquid L (or a predetermined liquid) is supplied from the nozzle 91 toward the wafer W after cutting. In the wire removing step (step S3), while supplying the processing liquid L to the wafer W, the wire 3 is moved in the direction opposite to the direction in which the single crystal C is cut, and the wire 3 is removed from the wafer W.

In this way, even when the wire saw device 100 is used, when the wire 3 is removed from the plurality of wafers W, the wire 3 is not caught on the wafer W and the wafer W is not damaged. The wire 3 can be removed from W.

Hereinafter, examples will be described. The present invention is not limited to the examples described below.

First, a single crystal of lithium tantalate having a size of φ150 mm and a length of 255 mm was prepared. This single crystal was supported on a pedestal having a thickness of 20 mm with an epoxy adhesive, and the pedestal was fixed to a slicing pedestal. An orientation flat formed of a single crystal was aligned with the surface of the pedestal and fixed to the pedestal with an adhesive. After that, a slicing table on which the single crystal was fixed was attached to the wire saw device, and the single crystal was pressed against the wire while supplying the processing liquid to start cutting the single crystal. For cutting the single crystal, the thickness of the wafer was 0.28 mm and the pitch between the wafers was 0.42 mm. After cutting the single crystal, the wire was cut into the pedestal by 5 mm to complete the cutting.

Next, the wire was removed (pulled out). First, with the wire stopped, polypropylene receiving plates having a length of about 30 cm, a width of 21 cm, and a thickness of 0.5 mm were placed on both sides of the cut wafer at a position 5 cm away from the cut wafer on the wire. It was placed. Then, the processing liquid was supplied at 40 (l / min). It was confirmed that the processing liquid flowed on the receiving plate and was supplied to a plurality of wafers. Subsequently, while supplying the processing liquid, the plurality of wafers were moved upward at a speed of 10 mm / min, and the wires were removed from the plurality of wafers. During this period, the wire was not caught on the side surface of the wafer and the side surface of the wafer was not damaged.

Comparative example

Using a wire saw device as in the examples, a single crystal of lithium tantalate was cut with a wire to form a plurality of wafers, and the wire was removed from the wafer. When removing the wire, the wafer is moved upward at a speed of 10 mm / min while feeding the wire at 1 to 3 mm / min without placing the backing plate on the wire and supplying the processing liquid to the wafer. The wire was removed from the plurality of wafers. During this time, the wire was caught on the side surface of the wafer three times, and each time the wire was stopped moving upward, the wire was released from being caught, and then the wafer was repeatedly moved to the information. When observing the side surface of the wafer after removing the wire, it was confirmed that the wire was rubbed and scratched on the side surface of the wafer.

As described above, according to the wire removing method according to the embodiment, the wire can be removed from the wafer without the problem of being caught on the wafer and without damaging the wafer, whereas in the comparative example, the wire is It was confirmed that a problem of being caught on the wafer occurred and that the side surface of the wafer was scratched.

Although the embodiments and examples of the present invention have been described above, the technical scope of the present invention is not limited to the above-described embodiments and examples. It will be apparent to those skilled in the art that various changes or improvements can be made to the above embodiments and examples. In addition, the technical scope of the present invention also includes a form in which such a modification or improvement is added. In addition, one or more of the requirements described in the above-described embodiments may be omitted. In addition, the requirements described in the above-described embodiments and the like can be combined as appropriate. Further, the execution order of each process shown in the present embodiment can be realized in any order as long as the previous process is not used in the subsequent process. Further, even if the operations in the above-described embodiment are described using "first", "next", "continued", etc. for convenience, it is not essential to carry out the operations in this order.

When the composition of the single crystal C is _{a brittle material such as lithium tantalate (LiTaO 3} (LT)) and lithium niobate (LiNbO ₃ (LN)), the effect of the wire removing method according to the above-described embodiment ( Prevention of catching of the wire 3 and prevention of damage to the side surface of the wafer W) is more remarkable than the conventional method. That is, in the present embodiment, when the wire 3 is removed, it does not get caught in the wafer W and induce damage to the wafer W. Therefore, this embodiment can be suitably used when forming a wafer W from a single crystal C of a brittle material such as _{lithium tantalate (LiTaO 3} (LT)) and lithium niobate (LiNbO _{3 (LN)).} it can.

1,100 ... wire saw device, 2a, 2b, 2c ... rotating roller, 3 ... wire, 4 ... wire row, 6 ... slice stand, 7 ... pedestal, 8 ... -Mounting part, 9 ... Liquid supply part, 91 ... Nozzle, C ... Single crystal, L ... Processing liquid (predetermined liquid), Sc ... Circumferential surface, T ... Support Member, W ... Wafer, X1, X2, X3, X4, X5 ... Receiving plate, X2a ... Support, X3a ... Inclined surface, X4a ... Edge, X4b ... Side wall

Claims (6)

A method in which a single crystal held on a pedestal is cut into a plurality of wafers using a wire of a wire saw device, and then the wire is removed from the plurality of wafers.
Supplying a predetermined liquid to the wafer and
A method for removing a wire, which comprises moving the pedestal relative to the wire in a direction opposite to the direction in which the single crystal is cut. The wire removing method according to claim 1, wherein the predetermined liquid is a processing liquid supplied at the time of cutting the single crystal. The wire removing method according to claim 1 or 2, wherein the predetermined liquid is supplied to the wafer via a receiving plate. The wire removing method according to claim 3, wherein the receiving plate is placed on the wire or the receiving plate is supported by a support member prior to the supply of the predetermined liquid. The third or fourth aspect of the present invention, wherein the receiving plate is arranged so as to be inclined so that the predetermined liquid is directed toward the wafer, or has an inclined surface such that the predetermined liquid is directed toward the wafer. How to remove the wire. The wire removing method according to any one of claims 3 to 5, wherein the receiving plate has a side wall at an edge in a direction intersecting a direction of supplying the predetermined liquid.

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