JP7302213B2 - SINGLE CRYSTAL PRESSING JIG, WIRE SAW DEVICE, AND SINGLE CRYSTAL CUTTING METHOD - Google Patents

Description

The present invention relates to a single crystal holding jig, a wire saw device, and a single crystal cutting method.

2. Description of the Related Art Conventionally, a multi-wire saw device (also called a wire saw device) is known as a method for cutting a single crystal (single crystal ingot) into wafers. For example, in the cutting method using a wire saw device described in Patent Document 1 below, there are three (or two) main shaft rollers, and grooves are formed on the outer periphery of the main shaft rollers at a pitch that matches the thickness of the target wafer. A wire saw device is used in which a single wire is wound along the groove of the main shaft roller. The main shaft roller is rotated to run the wire, and the main body table to which the single crystals are fixed is operated to press the single crystals against the wire. disconnect.

In the above processing method, the workpiece is pressed against a plurality of rows of ultra-fine wires (wire rows) arranged in parallel at a constant pitch, and while the wires are fed in the wire direction, abrasive grains are contained between the workpiece and the wires. There is a method of polishing and cutting by supplying a working fluid (also called slurry), and a method of polishing and cutting the workpiece while feeding a wire, to which diamond is electrodeposited or fixed by an adhesive, in the line direction. Using these methods, a large number of wafers of constant thickness are simultaneously formed from a single crystal.

In a conventional procedure for slicing a single crystal into wafers, first, the single crystal is fixed to a slicing table of a wire saw device with an adhesive via a pedestal. After that, the slicing table on which the single crystal is fixed is installed on the wire saw device. Next, the cutting of the single crystal by the wire saw device is started, the slicing table to which the single crystal is fixed is moved to the processing section, and the single crystal is cut by the wire. In this cutting, the pedestal is cut to about 5 mm in addition to the single crystal. The cut wafer has a thickness of about 0.2 to 2 mm, and the edge portion of the wafer is held only by an adhesive.

Japanese Patent Application Laid-Open No. 2001-001248 Japanese Patent Application Laid-Open No. 2004-001409 JP 2011-009590 A

When cutting the single crystal into wafers using the wire saw device, as the single crystal is cut, a plurality of wafer-like portions are gradually formed, and the single crystal is completely cut to form a plurality of wafers. be. During cutting, if vibration (shake) occurs in the wafer-shaped portion formed by cutting, there is a problem that the amount of waviness and warpage of the finally obtained wafer increases, and the thickness of the wafer (plate thickness) There was a problem that variation occurred. In the cutting of the single crystal, a wafer-shaped portion is gradually formed, but since the single crystal is fixed only on one side of the pedestal, the wafer-shaped portion formed by cutting is in a state of being prone to vibration. there is As a result, the amount of waviness and warpage of the obtained wafer is increased, and the variation in thickness is considered to be increased. If the amount of waviness and warpage of the wafer increases, and the variation in thickness becomes large, waviness, warpage, plate thickness, etc. become out of specification, making it impossible to ship as a product, which is one of the causes of deterioration in productivity. was In addition, if vibration (shake) occurs during the cutting of the single crystal, the wafer is held in a state of being adhered to the pedestal with a small bonding area, so the wafer may easily drop or fall.

In order to suppress the increase (deterioration) of the amount of undulation and warpage and the variation in thickness, it is necessary to suppress the vibration of the single crystal during cutting, and various cutting methods have been developed. For example, Patent Document 2 below proposes a method of cutting a columnar single crystal by bringing a dummy plate into contact with both end faces of the single crystal. In this cutting method, vibration of the single crystal during cutting can be suppressed in the vicinity where the dummy plate material is in contact, but if the single crystal to be cut is long, the single crystal may be cut away from the dummy plate material. There is a drawback that it is difficult to suppress the vibration near the center of the

Further, in Patent Document 3, by attaching an auxiliary jig made of resin or the like to the cutting start side of the single crystal to be cut, and cutting the single crystal from the auxiliary jig side, vibration of the single crystal during cutting described above is suppressed. has been proposed. However, with this method, although it is possible to suppress the vibration of the single crystal in the initial stage of cutting, the single crystal is cut together with the auxiliary jig. It has the disadvantage of being uncontrollable.

SUMMARY OF THE INVENTION Accordingly, the present invention is intended to solve the above-mentioned problems, and it is an object of the present invention to suppress waviness, warpage, and variation in thickness of the resulting wafer by suppressing vibration of the single crystal during cutting. .

According to the aspect of the present invention, when cutting a single crystal using a wire saw device that cuts the single crystal into a plurality of wafers by relatively moving the single crystal and the wire arrays arranged at predetermined intervals, A jig to be used, which is a contact portion that contacts an end portion of each of a plurality of wafer-shaped portions formed by cutting during cutting of a single crystal by a wire saw device in the moving direction of the single crystal, and an elastic body. and a pressing part that presses the contacting part in a direction opposite to the moving direction of the single crystal by the elastic force of the elastic body, and a supporting part that supports the pressing part. be.

Also, the contact portion may be formed of an elastic body at portions that contact the plurality of wafer-shaped portions. Also, the single crystal holding jig may be configured to be detachable from the wire saw device. Moreover, you may provide the regulation part which regulates the pressurization force by a pressurization part below predetermined value. In addition, the abutting portion does not abut against the single crystal before the single crystal reaches the predetermined starting position, but contacts and pressurizes the single crystal from the time when the single crystal is cut from the predetermined starting position until the cutting is completed. , the predetermined starting position may be set to 2/3 or less of the diameter of the single crystal.

Further, according to an aspect of the present invention, there is provided a wire saw apparatus for cutting a single crystal into a plurality of wafers by relatively moving the single crystal and a wire row arranged at a predetermined interval, the single crystal A wire saw device is provided that includes a holding jig.

Further, according to the aspect of the present invention, the single crystal is cut by using a wire saw device that cuts the single crystal into a plurality of wafers by relatively moving the single crystal and a wire row arranged at a predetermined interval. In the method for cutting a single crystal, while the single crystal is being cut by a wire saw, the ends of each of the plurality of wafer-shaped portions formed by cutting are pressed against the above-described single crystal holding jig. A method for severing a single crystal is provided that includes applying pressure with a tool opposite the direction of travel.

According to the aspect of the present invention, since the wafer-shaped portion formed by cutting is pressurized and held while the single crystal is cut by the wire saw device, the vibration of the wafer-shaped portion during cutting is suppressed, and the wafer obtained is waviness, warpage, and variations in thickness can be suppressed. Further, according to the aspect of the present invention, it is possible to suppress the dropping (or falling) of the wafer after cutting. In addition, according to the aspect of the present invention, the recovery rate (yield) of wafers can be improved due to the above effects. Further, according to the aspect of the present invention, the configuration is simple, so that it can be easily implemented and used easily.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows the outline of an example of the wire saw apparatus which concerns on embodiment. It is a front view which shows the outline of an example of a wire saw apparatus. FIG. 4 is a front view showing the operation of the wire saw device before cutting the single crystal and before the single crystal comes into contact with the jig. FIG. 10 is a front view showing the operation of the wire saw device during cutting of the single crystal and immediately after the single crystal comes into contact with the jig. FIG. 4 is a front view showing the operation of the wire saw device after cutting the single crystal; FIG. 10 is a side view showing an example of the operation of the jig according to the modification, showing a state before the single crystal contacts the jig; Following FIG. 6, the state when the single crystal comes into contact with the jig is shown. Continuing from FIG. 7, the state when the restricting portion is actuated is shown. Continuing from FIG. 8, the state after the restricting portion is actuated is shown.

Hereinafter, the present invention will be described with reference to the drawings. However, the present invention is not limited to this. In addition, in order to explain the embodiments in the drawings, the scale is changed as appropriate, such as by enlarging or emphasizing a portion. Also, in each of the following drawings, directions in the drawings will be explained using an XYZ coordinate system. In this XYZ coordinate system, the vertical direction is the Z direction, and the horizontal directions are the X direction and the Y direction. In addition, for each of the X direction, Y direction, and Z direction, the side (direction) indicated by the arrow is appropriately referred to as the + side (direction) (eg, +X side (direction)), and the opposite side (direction) is referred to as It is called the - side (direction) (for example, the -X side (direction)). Further, in this specification, when a range of numerical values is described as "A to B", it means "A or more and B or less".

[Embodiment]
A method for cutting a single crystal, a wire saw device, and a jig for holding a single crystal (hereinafter abbreviated as "jig") according to the present embodiment will be described below with reference to the drawings.

First, an outline of the wire saw device used in this embodiment will be described. FIG.1 and FIG.2 is a figure which shows the outline of an example of the wire saw apparatus 1 which concerns on this embodiment. FIG. 1 is a perspective view. FIG. 2 is a front view seen from the -Y side.

The wire saw device 1 according to the present embodiment includes wire rows 2 arranged at predetermined intervals, and by relatively moving the cylindrical single crystal C and the wire rows 2, the single crystal C is separated into a plurality of wafers W. It is a device that cuts into In addition, in the wire saw device 1, the configuration of a known wire saw device can be used for the configuration other than the jig 10, which will be described later. An example of the wire saw device 1 will be described below.

As shown in FIGS. 1 and 2, the wire saw device 1 includes a slicing table holder 3, a slicing table 4, a plurality of rollers R (three in this example), and a predetermined interval between the plurality of rollers R. A wire row 2 stretched through and a jig 10 are provided. As shown in FIG. 1, the wire saw device 1 moves the wire row 2 and the single crystal C in relative directions by moving the single crystal C in the +Z direction or the −Z direction. The wire saw device 1 moves the wire row 2 and the single crystal C in relative directions, and runs the wire row 2 in one direction or reciprocating direction while pressing the single crystal C against the wire row 2, thereby simultaneously cutting the single crystal C. A plurality of wafers W (see FIG. 5) are cut. The wire saw device 1 may be configured to move the wire row 2 with respect to the fixed single crystal C, or may be configured to move the single crystal C and the wire row 2 .

A single crystal C to be processed by the wire saw device 1 is fixed via a pedestal 5 to a slicing table holder 3 and a slicing table 4 fixed together. The single crystal C is, for example, a cylindrical ingot. Any single crystal C can be used, and for example, the size, composition, etc. of the single crystal C are not particularly limited.

The slicing table holder 3 is detachable from the wire saw device 1 . By removing the slicing table holder 3 from the wire saw device 1 , the single crystal C can be fixed to the slicing table holder 3 and the cut wafer W can be removed from the wire saw device 1 . For identification purposes, the single crystal C may be processed to have an orientation flat (also referred to as an orientation flat) by grinding a part of the outer peripheral surface into a flat shape. When the single crystal C is cut into a plurality of wafers W, the pedestal 5 cuts the wafer W and cuts a part of the pedestal 5 in order to reliably cut the single crystal C. As shown in FIG. Therefore, the material of the base 5 is preferably resin, glass, or the like. Since the pedestal 5 is cut as described above, the thickness (dimension in the Z direction) of the pedestal 5 is about 5 mm or more, preferably 10 mm or more, and more preferably about 20 mm.

The fixation of the slicing table 4 and the base 5 and the fixation of the base 5 and the single crystal C can be performed by bonding with an adhesive. The adhesive used at this time is not particularly limited, but it is preferable to use an epoxy-based adhesive that can be easily peeled off after cutting. If the single crystal C has an orientation flat, when fixing the pedestal 5 and the single crystal C, the surface of the orientation flat may be adhered to the pedestal 5 . When the surface of the orientation flat is aligned with the pedestal 5 and adhered, the area to be adhered increases compared to the case where the circumferential surface of the single crystal C is adhered to the pedestal 5, so the adhesion becomes stronger.

When the single crystal C is cut by the wire saw device 1, the slicing table holder 3 to which the single crystal C is fixed as described above is installed in the wire saw device 1, and the cutting is performed. The single crystal C is attached to the wire saw device 1 via the slicing table holder 3 , the slicing table 4 and the pedestal 5 . In the wire saw device 1, the central axis of the single crystal C (an axis parallel to the Y direction) is arranged in a direction orthogonal to the direction in which the wire row 2 travels (X direction).

In the wire saw device 1, as described above, the slicing table 4 is moved in the -Z direction (downward) by the driving device (not shown), and thus the wire train traveling on the single crystal C in the X direction is driven by the rollers R. 2, the single crystal C is cut into a plurality of wafers W at the same time. In the wire saw device 1 , the single crystal C is gradually moved in the −Z direction and cut by the wire row 2 . During cutting, the single crystal C is formed with a plurality of wafer-like portions Wa. The wafer-like portion Wa is the portion on the −Z side of the wire row 2 in the single crystal C in the state of FIG. 4, which will be described later. The wafer-shaped portion Wa becomes a thin plate. From the state shown in FIG. 4, the single crystal C is gradually moved in the -Z direction and cut by the wire row 2, so that the single crystal C is cut into a plurality of wafers W as shown in FIG. The thickness of the wafer W is, for example, 0.2 mm to 1.0 mm. The single crystal C can be cut into wafers W having a predetermined thickness by appropriately adjusting the diameter of the wires 6, the pitch between the wires 6 (interval between the wires 6 in the Y direction in FIG. 1), and the like.

Next, the jig 10 will be explained. 3 to 5 are enlarged views of the jig 10 portion of the wire saw device 1. FIG. 3 to 5 are front views seen from the -Y direction. FIG. 3 shows the state before the single crystal C is cut, and shows the state before the single crystal C comes into contact with the jig 10. FIG. FIG. 4 shows the state during cutting of the single crystal C, and shows the state immediately after the single crystal C comes into contact with the jig 10 . FIG. 5 shows the state of the single crystal C after cutting.

The jig 10 is installed in the wire saw device 1 (see FIG. 1). As shown in FIGS. 3 to 5, the jig 10 is installed on the movement path of the single crystal C when the single crystal C is cut by the wire saw device 1. As shown in FIG. The jig 10 is installed on the side opposite to the single crystal C before cutting (the −Z side in FIG. 3) with respect to the wire row 2 . The jig 10 is installed beyond the wire row 2 in the direction in which the single crystal C being cut moves. The jig 10 is detachable from the wire saw device 1 .

The jig 10 includes a contact portion 11 , a pressure portion 12 and a support portion 13 . As shown in FIGS. 4 and 5, the contact portion 11 is formed on the moving direction side of the single crystal C in each of a plurality of wafer-shaped portions Wa formed by cutting while the single crystal C is cut by the wire saw device 1. (the direction of movement relative to the wire row 2 during cutting, the -Z side in FIG. 3).

The contact portion 11 is configured to support the entire length of the cut single crystal C (the entire length in the Y direction). The contact portion 11 is configured to contact each of a plurality of wafer-shaped portions Wa formed by cutting the single crystal C. As shown in FIG.

The contact portion 11a (the surface facing the single crystal C, the surface on the +Z side in FIG. formed into a shape. When the shape of the contact portion is the R shape, the contact area with the wafer-shaped portion Wa formed by cutting can be increased compared to the planar configuration, so that the contact portion can be held more effectively, These positional deviations, shakes, and vibrations (hereinafter sometimes referred to as “vibrations, etc.”) can be suppressed.

The material (formation material) of the contact portion 11 is not particularly limited, but the main body portion (part other than the contact portion) uses water such as grinding liquid when cutting, so it is preferable to use a rust-resistant material such as stainless steel. Further, the contact portion 11a is preferably an elastic body 11b. When the contact portion 11a is composed of the elastic body 11b, damage (impact) when the wafer-like portion Wa contacts the contact portion 11 can be reduced. Further, when the contact portion 11a is composed of the elastic body 11b, it is possible to restrain and hold down the wafer-shaped portion Wa formed by cutting, so that the above-described vibration and the like can be further effectively restrained. can be done. The material (forming material) of the elastic body 11b is not particularly limited, but may be silicon rubber or soft rubber, for example. It is preferable that the elastic body 11b has elasticity capable of sandwiching each wafer-shaped portion Wa (sandwiched between the wafer-shaped portions Wa) when pushed by the wafer-shaped portions Wa. As such elastic force, for example, when the elastic body 11b is made of a rubber material such as silicon rubber, the hardness thereof is preferably 30 degrees to 40 degrees.

The pressure part 12 is connected to the contact part 11 and supports the contact part 11 . The pressurizing part 12 has an elastic body 12a. The pressing portion 12 presses the contact portion 11 in the opposite direction (+Z direction) to the moving direction of the single crystal C (−Z direction in FIG. 5) by the elastic force of the elastic body 12a. As a result, the wire saw device 1 (jig 10) of the present embodiment moves the single crystal C and the wire row 2 relative to each other by the wire saw device 1, so that the single crystal C is cut while the single crystal C is being cut. The abutment portion 11 abuts against the end portion of the wafer-shaped portion Wa on the moving direction side of the single crystal C and presses the single crystal C in the direction opposite to the moving direction.

The elastic body 12a is, for example, a spring. The elastic bodies 12a are evenly arranged with respect to the contact portion 11 so that the contact portion 11 presses the plurality of wafer-shaped portions Wa with a uniform pressure force. For example, in this embodiment, as shown in FIG. 1, six elastic bodies 12a, two in the X direction and three in the Y direction, are evenly arranged with respect to the contact portion 11. As shown in FIG. It should be noted that the number and arrangement positions of the elastic bodies 12a are not limited to the above example, and may be other modes. For example, three or more elastic bodies 12a may be provided in the X direction and two or more rows in the Y direction.

The pressure part 12 supports the contact part 11 and improves the adhesion between the wafer-shaped portion Wa formed by cutting and the contact part 11. Therefore, an appropriate pressure is required until the cutting is completed. . For this pressurization, for example, the elastic force (elastic force) of a spring can be used as in the present embodiment. When the pressurizing part 12 is composed of a spring or the like, the wafer-shaped portion Wa can be pressed with a gradually increasing pressurizing force. As a result, shaking (vibration) of the wafer-shaped portion Wa, which increases as the cutting of the single crystal C progresses, can be effectively suppressed by pressing the wafer-shaped portion Wa with a pressure that gradually increases. The material of the elastic body 12a (spring) is not particularly limited, but like the contact portion 11, a material that is resistant to rust is preferable.

The contact portion 11 of the present embodiment does not contact the single crystal C before the single crystal C reaches the predetermined start position, but contacts the single crystal C from the predetermined start position until the cutting is completed. Press and hold. The predetermined start position is preferably set to 2/3 or less of the diameter of the single crystal C, more preferably set to 1/2 or less of the diameter of the single crystal C. More preferably, it is 1/3 or more and 1/2 or less. That is, the timing at which the contact portion 11 starts pressing the single crystal C during cutting is preferably before 2/3 of the diameter of the single crystal C is cut, and 1/3 of the diameter of the single crystal C is cut. Preferably before 2 is cut. In particular, it is more preferable to start pressing by the contact portion 11 while the single crystal C is cut by an amount of 1/3 to 1/2 of the diameter. When starting to press the single crystal C that has been cut to more than 2/3 of the diameter by the abutting portion 11, warping or the like may occur in the already cut portion. By holding down the single crystal C over 2/3 of the diameter, preferably over 1/2 of the diameter before it is cut, the cut amount of the single crystal C is small and the wafer-like portion Wa is shaken ( Therefore, the single crystal C can be stably cut.

The pressing force (the force pressing the single crystal C) by the contact portion 11 may be of a degree that suppresses shaking of the wafer-shaped portion Wa during cutting. This pressure can be appropriately set depending on the material of the single crystal C to be cut, the diameter of the single crystal C, the thickness of the wafer W formed by cutting, and the like. For example, when an ingot of lithium tantalate (LT) single crystal C, which is a brittle material, has a diameter of 100 mm, a length of 250 mm, and a wafer thickness of 0.3 mm, the pressure is 5 to 20 N. is preferred.

The support portion 13 supports each portion of the jig 10 . The support portion 13 is fixed to the wire saw device 1 . In this embodiment, the support portion 13 supports the contact portion 11 and the pressure portion 12 . The support portion 13 is fixed to the wire saw device 1 so as not to be displaced during cutting. The support portion 13 (jig 10) is fixed to a portion of the wire saw device 1 that does not move during cutting. In this configuration, the configuration can be simplified compared to the configuration in which the supporting portion 13 (jig 10) is connected (supported) to a portion of the wire saw device 1 that is movable during cutting. For example, the support part 13 (jig 10) may be fixed in the wafer recovery container 8 or the like for recovering the dropped wafer W, as in the present embodiment. The method (configuration) for fixing the support portion 13 (jig 10) to the wire saw device 1 varies depending on the configuration of the wire saw device, but can usually be implemented according to the configuration of the wire saw device. Although the material (formation material) of the support portion 13 is not particularly limited, it is preferable to use a material that is resistant to rust, like the contact portion 11 and the pressure portion 12 .

As described above, the wire saw device 1 (jig 10) of the present embodiment is formed by cutting the single crystal C while the single crystal C is being cut by the relative movement of the single crystal C and the wire row 2 by the wire saw device 1. The abutment portion 11 abuts on the ends of the plurality of wafer-shaped portions Wa on the moving direction side of the single crystal C to press the single crystal C in the direction opposite to the moving direction. With this configuration, the wafer-like portion Wa can be held while the single crystal C is being cut, and vibration (shake) thereof can be suppressed.

In addition, the wire saw device 1 (jig 10) of the present embodiment presses (presses) the edge of the wafer-shaped portion Wa formed by cutting on the moving direction side of the single crystal C during cutting. Since the wafer-like portion Wa is sandwiched and held between the base 5 and the contact portion 11, it can be prevented from falling during cutting. In addition, in the wire saw device 1 (jig 10) of the present embodiment, even after the single crystal C is cut, the wafer W formed by cutting is brought into contact with the pedestal 5 in the same manner as described above, as shown in FIG. Since it is sandwiched and held between the part 11, it is possible to prevent it from falling or falling.

Since the jig 10 of the present embodiment is composed of the contact portion 11, the pressure portion 12, and the support portion 13, the structure is simple and can be easily implemented. Since it can be used only by attaching it to the wire saw device 1 and fixing it, it can be used easily. Moreover, the jig 10 of the present embodiment can be attached to and detached from the wire saw device 1 as described above. With this configuration, the jig 10 of the present embodiment can be easily implemented and used by attaching it to an existing wire saw device, and the jig 10 alone can be configured independently of the wire saw device 1 of the present embodiment. It can also be distributed as

As described above, the jig 10 of the present embodiment cuts the single crystal C into a plurality of wafers W by relatively moving the single crystal C and the wire rows 2 arranged at predetermined intervals. A jig used when cutting a single crystal C with the wire saw device 1, and is a single crystal in each of a plurality of wafer-shaped portions Wa formed by cutting during the cutting of the single crystal C with the wire saw device 1. It has a contact portion 11 that contacts the end of the single crystal C on the moving direction side, and an elastic body 12a. and a supporting portion 13 that supports the pressing portion 12 . Moreover, the wire saw device 1 of this embodiment includes the jig 10 described above. According to the configuration of the above-described jig 10 (wire saw device 1), as described above, it is possible to suppress the vibration (shake) of the single crystal during cutting, and the waviness, warpage, and variations in thickness of the resulting wafer. can be suppressed.

Next, a method for cutting a single crystal according to this embodiment will be described. The single crystal cutting method of the present embodiment is a method that is carried out using the jig 10 (wire saw device 1) described above, and the single crystal C is cut by relatively moving the single crystal C and the wire row 2. A single crystal cutting method for cutting a single crystal C using a wire saw device for cutting into a plurality of wafers W, wherein a plurality of wafer-like portions Wa are formed by cutting during cutting of the single crystal C by the wire saw device. presses the end portion of the single crystal C on the moving direction side in each of the above-described jigs 10 in the direction opposite to the moving direction of the single crystal C. Since this single crystal cutting method uses the jig 10 (wire saw device 1) described above, vibration (shake) of the single crystal during cutting can be suppressed as described above, and waviness of the obtained wafer, It is possible to suppress the occurrence of warpage and variations in thickness.

Moreover, according to the jig 10, the wire saw device 1, and the single crystal cutting method of the present embodiment, it is possible to prevent the wafer from falling (or falling) after cutting. According to the jig 10, the wire saw device 1, and the single crystal cutting method of the present embodiment, the recovery rate (yield) of wafers can be improved due to the above effects. Moreover, the jig 10, the wire saw device 1, and the single crystal cutting method of the present embodiment can be easily implemented with a simple configuration and can be used easily. In addition, the jig 10, the wire saw device 1, and the single crystal cutting method of the present embodiment can be suitably used for cutting a brittle single crystal C such as lithium tantalate or lithium niobate.

When a spring is used for the pressure member 12 as in the above example, the pressure applied to the wafer-like portion Wa increases as the single crystal C is cut. If the single crystal C with a small diameter or the thickness of the wafer W is thick, there is no problem. may occur. For this reason, a mechanism (mechanism for regulating the pressure) may be provided to prevent the application of pressure greater than or equal to a predetermined value to the wafer-shaped portion Wa. When this mechanism is provided, the above problems can be suppressed. An example of a mechanism for regulating the above pressure will be described below.

FIGS. 6 to 9 are side views of an example of a jig 10A according to a modification when viewed from the +X side. 6 to 9 correspond to the direction when the wire saw device 1 in FIG. 1 is viewed from the +X side. FIG. 6 shows the state before the single crystal C contacts the jig 10A. FIG. 7 shows a state following FIG. 6, and shows a state when the single crystal C is in contact with the jig 10A. FIG. 8 shows a state following FIG. 7 and shows a state when the restricting portion is actuated. FIG. 9 shows a state subsequent to FIG. 8 and shows a state after the restricting portion has been actuated.

For example, the jig 10A according to the modified example has a support portion 13 (first support portion), a contact portion 11, a pressure portion 12A, a second support portion 16, and a restriction portion in addition to the jig 10A described above. 15. The contact portion 11 is similar to the jig 10 . 12 A of pressurization parts are provided with the elastic body 12a which pressurizes the contact part 11 like the jig|tool 10, and the elastic body 12b. The elastic body 12b is composed of a spring. The pressurizing portion 12A has a two-stage structure of an elastic body 12a and an elastic body 12b. The elastic body 12 a is provided on the second support portion 16 and connected to the contact portion 11 . The second support portion 16 is connected to the support portion 13 via the elastic body 12b, and the elastic force of the elastic body 12b moves the single crystal C in the direction (+Z direction) opposite to the moving direction (-Z direction) in the wafer-like shape. A pressurizing force is applied to pressurize the portion Wa of . In the state shown in FIG. 7, the wafer-shaped portion Wa is pressed by the elastic forces of the elastic bodies 12a and 12b. When the cutting is further advanced from the state shown in FIG. 7, the tip of the restricting portion 15 provided on the second support portion 16 and extending in the direction of the slicing table 4 contacts the slicing table 4 as shown in FIG. As a result, the elastic body 12a does not contract any more than the state shown in FIG. 8, and the pressure applied from the elastic body 12a to the wafer-shaped portion Wa is regulated. That is, the restricting portion 15 restricts the above-mentioned pressure force to a predetermined value or less by restricting the contraction amount of the elastic body 12a to a predetermined value or less. As the cutting progresses further from the state shown in FIG. 8, only the elastic body 12b contracts without contracting the elastic body 12a due to the action of the restricting portion 15 and the like, as shown in FIG. In this state, the pressure applied from the elastic body 12a to the wafer-shaped portion Wa is the same as in the state shown in FIG. Note that the mechanism for regulating the applied pressure is not limited to the above example, and other configurations may be used. For example, the mechanism for regulating the applied pressure may be configured such that the regulating portion 15 described above is connected to the slice table 4 side and contacts the second support portion 16 . The jig 10A of the present example is configured by the support portion 13 (first support portion), the contact portion 11, the pressure portion 12A, the second support portion 16, and the restriction portion 15, and thus has a simple configuration. , and it can be used easily by simply attaching it to the wire saw device 1 and fixing it as described above.

Examples of the present invention will be specifically described below. In addition, the present invention is not limited at all by the examples.

[Example 1]
In Example 1, the method for cutting a single crystal according to the above-described embodiment was carried out using the wire saw device 1 (jig 10) shown in FIG. A single crystal C of lithium tantalate (hereinafter referred to as LT) having a size of φ100 mm and a length of 250 mm was prepared. This single crystal C was fixed to a slicing table 4 and a pedestal 5 having a thickness of 20 mm was fixed with an epoxy adhesive. An orientation flat portion of the single crystal C was aligned with the surface of the pedestal 5 and fixed on the pedestal 5 with an adhesive.

Next, the jig 10 was installed in the wafer collection container 8 of the wire saw device 1 . The jig 10 was fixed in the wafer collection container 8 by screwing the supporting portion 13 of the jig 10 . In the jig 10, the contact portion 11, the pressure portion 12 (spring), and the support portion 13 are made of stainless steel. The length was set to 300 mm. Silicon rubber was used for the elastic body of the contact portion 11 .

Thereafter, the slicing table 4 on which the single crystal C was fixed was attached to the wire saw device 1, and cutting of the single crystal C was started. This cutting was performed under the conditions that the thickness of the obtained wafers W was 0.29 mm and the pitch between the wafers W was 0.43 mm. When the 1/2 diameter of the single crystal C is cut, the elastic member 11b of the contact portion 11 is brought into contact with the wafer-shaped portion Wa formed by cutting, thereby starting the pressing by the contact portion 11. , this pressing was continued until the end of cutting. The pressing force (pressing force) at this time was 10 to 20N.

After cutting, the slicing table 4 was removed from the wire saw device 1, the adhesive was removed, and the wafers W were recovered one by one. During this time, no drop of the wafer W was confirmed.

After collecting the wafer W, a cleaning operation is performed, and the state of warpage of the wafer W (A direction: cutting direction (Z direction in FIG. 1): B direction: running direction of the wire row 2 (X direction in FIG. 1)) and thickness Thickness variation (thickness difference=“maximum thickness of wafer”−“minimum thickness of wafer”) was confirmed. Tables 1 and 2 show the measurement results of the amount of warpage of the wafer W and the variation in thickness (thickness difference). The results shown in Tables 1 and 2 are obtained by measuring 18 wafers selected from a plurality of cut wafers W.

[Comparative Example 1]
The test was conducted in the same manner as in Example 1 except that the jig 10 was not used. Cutting of the single crystal C was completed without any problems. However, when the slicing table 4 was removed from the wire saw device 1 after the single crystal C was cut, several wafers W were confirmed to have fallen. After that, the adhesive was removed, the wafer W was collected, and the wafer W was evaluated in the same manner as in the first embodiment. The results are shown in Tables 1 and 2.

From the results of the above-described examples and comparative examples, the amount of warpage of the wafer W in the case of using the jig 10 (Example 1) is greater than that in the case of not using the jig 10 (Comparative Example 1). A reduction of 25% in the B direction and a reduction of 21% in the B direction were confirmed. Also, the "thickness difference" was confirmed to be reduced by 24% when compared with the standard deviation. As described above, the jig 10 (wire saw device 1) and the method for cutting a single crystal according to the present embodiment can suppress vibration (shake) of the single crystal C during cutting, and waviness of the obtained wafer W, The effect of suppressing warpage and variations in thickness was confirmed.

It should be noted that the technical scope of the present invention is not limited to the aspects described in the above embodiments and the like. One or more of the requirements described in the above embodiments and the like may be omitted. Also, the requirements described in the above-described embodiments and the like can be combined as appropriate. In addition, the requirements described in the above-described embodiments and the like may be improved in each member and changed in structure without departing from the gist of the present invention. In addition, as long as it is permitted by laws and regulations, the disclosure of all the documents cited in the above-described embodiments and the like is used as part of the description of the text.

DESCRIPTION OF SYMBOLS 1... Wire saw device 2... Wire row 3... Slice table holder 4... Slice table 5... Pedestal 6... Wire 8... Wafer collection container R... Roller C... Single crystal W... Wafer Wa... Wafer-like portion 10, 10A... Jig REFERENCE SIGNS LIST 11: contact portion 11a: contact portion 11b: elastic bodies 12, 12A: pressurizing portion 12a: elastic body 13: support portion 15: regulation portion 16: second support portion

Claims (7)

A jig used when cutting a single crystal using a wire saw device that cuts the single crystal into a plurality of wafers by relatively moving the single crystal and wire rows arranged at predetermined intervals, ,
an abutting portion that abuts against an end portion of each of a plurality of wafer-shaped portions formed by cutting during the cutting of the single crystal by the wire saw device, on the moving direction side of the single crystal;
a pressurizing part having an elastic body, and pressurizing the contact part in a direction opposite to the moving direction of the single crystal by the elastic force of the elastic body;
and a support part that supports the pressure part ,
A jig for holding a single crystal , wherein the supporting portion is fixed to a portion of the wire saw device that does not move during cutting . 2. The jig for holding a single crystal according to claim 1, wherein said abutting portion has a portion that abuts against said plurality of wafer-shaped portions formed of an elastic material. 3. The single crystal holding jig according to claim 1, wherein said single crystal holding jig is detachable from said wire saw device. The single crystal pressing jig according to any one of claims 1 to 3, further comprising a regulating portion that regulates the pressure applied by the pressing portion to a predetermined value or less. The contact portion does not contact the single crystal before the single crystal is cut from the predetermined start position, and is in contact with the single crystal from the time when the single crystal is cut from the predetermined start position until the cutting is completed. pressurized in contact,
The single crystal holding jig according to any one of claims 1 to 4, wherein said predetermined start position is set to 2/3 or less of the diameter of said single crystal. A wire saw device for cutting a single crystal into a plurality of wafers by relatively moving a single crystal and a wire row arranged at a predetermined interval,
A wire saw device comprising the single crystal holding jig according to any one of claims 1 to 5. A single crystal slicing method for slicing the single crystal using a wire saw device that cuts the single crystal into a plurality of wafers by relatively moving the single crystal and a wire row arranged at a predetermined interval, ,
6. During the cutting of the single crystal by the wire saw device, each of a plurality of wafer-shaped portions formed by cutting, the end portion of the moving direction side of the single crystal is cut into the single crystal according to any one of claims 1 to 5. 2. A method of cutting a single crystal, comprising applying pressure in a direction opposite to the direction of movement with the jig for holding the single crystal according to 1.

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