Notch formation position determination method, notch formation method, wafer manufacturing method, notch formation position determination device, notch formation device, and wafer manufacturing system

Abstract

A method for determining a notch formation position in a single crystal used for manufacturing a plurality of wafers having notches, the method comprising: a positional relationship acquisition step for acquiring a positional relationship between a plurality of notch formation candidate positions, which are specified on the basis of the crystal orientation of the single crystal, and the plane orientation of the single crystal; a first rotation angle calculation step for calculating a first rotation angle such that, when the single crystal is rotated around the central axis of the single crystal from a state in which the notch formation candidate positions are positioned at a slice start position, the positions in the vertical direction of the plane orientation and a target plane orientation when viewed from the center axis direction are the same; and a determination step for determining, as the notch formation position, the notch formation candidate position at which the absolute value of the first rotation angle is equal to or greater than a prescribed angle.

Description

Notch formation position determining method, notch forming method, wafer manufacturing method, notch formation position determining device, notch forming device, and wafer manufacturing system

[0001] The present invention relates to a method for determining a notch formation position, a notch formation method, a wafer manufacturing method, a notch formation position determination device, a notch formation device, and a wafer manufacturing system.

[0002] A conventional method is known in which a single crystal to be ground is cylindrically ground and a notch is formed on the single crystal to be ground to produce a single crystal to be sliced, and the single crystal to be sliced ​​is then sliced ​​to produce multiple wafers (see, for example, Patent Document 1). In the method described in Patent Document 1, the single crystal to be ground is cylindrically ground so as to pre-adjust the amount of misalignment between the crystal axis extending in the same direction as the crystal orientation of the single crystal ingot (single crystal to be ground) and the central axis of the single crystal to be ground. Next, candidate positions for forming a notch in the cylindrically ground single crystal to be ground are detected, and a notch is formed at the detected candidate positions to produce a single crystal to be sliced. The single crystal to be sliced ​​is then cut into blocks, and the blocks are attached to a work plate using the notch as a reference, and the work plate is attached to a wire saw. The single crystal to be sliced ​​is then sliced ​​using the wire saw to produce multiple wafers.

[0003] Japanese Patent Application Laid-Open No. 2017-212268

[0004] Incidentally, on the outer peripheral surface of a single crystal to be ground, multiple crystal axes corresponding to the crystal orientation of the crystal's central axis are present at equal intervals in the circumferential direction. For example, on the outer peripheral surface of a single crystal to be ground whose crystal central axis has a crystal orientation of <100>, four crystal axes with a crystal orientation of <110> are present. A notch representing the plane orientation is formed on one of the multiple crystal axes. Patent Document 1 does not disclose how the position of the notch is determined based on the multiple crystal axes. Therefore, with the method described in Patent Document 1, when a single crystal to be ground is sliced ​​to obtain wafers whose plane orientation matches the target plane orientation, damage may occur around the notch.

[0005] An object of the present invention is to provide a method for determining a notch formation position that can prevent damage to a wafer when slicing a single crystal, a notch formation method, a wafer manufacturing method, a notch formation position determination device, a notch formation device, and a wafer manufacturing system.

[0006] As a result of extensive research, the inventors discovered that if the distance from the slicing start position to the notch in the single crystal is too short, damage is likely to occur in the wafer starting from the end face of the notch formed on the outer periphery of the single crystal during slicing, and this finding led to the completion of the present invention.

[0007] (1) A method for determining a notch formation position of the present invention is a method for determining a notch formation position in a single crystal used for manufacturing a plurality of wafers having notches, and includes: a positional relationship acquisition step for acquiring a positional relationship between a plurality of candidate notch formation positions identified based on the crystal orientation of the single crystal and a plane orientation of the single crystal; a first rotation angle calculation step for calculating a first rotation angle such that, when the single crystal is rotated around a central axis of the single crystal from a state in which the candidate notch formation positions are located at a slice start position, the plane orientation and a target plane orientation are positioned in the same vertical direction as viewed from the central axis direction; and a determination step for determining, as the notch formation position, the candidate notch formation position such that the absolute value of the first rotation angle is equal to or greater than a specified angle.

[0008] (2) In the method of determining a notch formation position of the present invention, it is preferable that the specified angle is an acute angle, and the determining step determines, as the notch formation position, the notch formation candidate position where the absolute value of the first rotation angle is 90° or less.

[0009] (3) The method of the present invention for determining a notch formation position preferably includes a first horizontal rotation angle calculation step of calculating a first horizontal rotation angle such that, when the single crystal is rotated by the first rotation angle and then rotated horizontally around a vertical axis, the plane orientation when viewed from a direction orthogonal to the slice plane that is orthogonal to the slice plane of the single crystal coincides with the target plane orientation, and the determination step preferably determines, when there are multiple notch formation candidate positions whose absolute values ​​of the first rotation angle are equal to or greater than the specified angle, the notch formation candidate position with the smallest first horizontal rotation angle as the notch formation position.

[0010] (4) The notch forming method of the present invention includes a notch formation position determination step of determining the notch formation position by any one of the notch formation position determination methods (1) to (3), and a notch forming step of forming the notch at the notch formation position.

[0011] (5) The method for manufacturing a wafer of the present invention includes the steps of: forming a notch in the single crystal by the notch forming method of (4); mounting the single crystal on a slicing device so that the plane orientation when viewed from a direction perpendicular to the slicing plane of the single crystal coincides with the target plane orientation; and slicing the single crystal from the slicing start position with the slicing device to manufacture the plurality of wafers.

[0012] (6) A method for manufacturing a wafer of the present invention includes a notch formation position determining step of determining the notch formation position by the notch formation position determining method of (3), a notch forming step of forming the notch at the notch formation position, a first mounting step and a second mounting step of mounting the single crystal to a slicing device, and a slicing step of manufacturing the plurality of wafers by slicing the single crystal from the slicing start position with the slicing device, wherein the determining step is performed when there is no notch formation candidate position where the absolute value of the first rotation angle is equal to or greater than the specified angle. If the absolute value of the first rotation angle is not equal to or greater than the specified angle, the notch formation candidate position where the absolute value of the first rotation angle is less than the specified angle is determined as the notch formation position, and if the notch formation candidate position where the absolute value of the first rotation angle is equal to or greater than the specified angle is determined as the notch formation position, the notch formation step, the first mounting step of mounting the single crystal on the slicing device based on the first rotation angle and the first horizontal rotation angle so that the plane orientation when viewed from a direction perpendicular to the slicing plane coincides with the target plane orientation, and the slicing step are performed, When the notch formation candidate position having an absolute value of a rotation angle less than the specified angle is determined as the notch formation position, when the single crystal is rotated about the central axis in a state where the notch formation position is located at the slice start position, the plane orientation when viewed from the central axis direction and the position of the target plane orientation in the vertical direction become different and the second rotation angle is larger than the specified angle; and a second horizontal rotation angle calculation step of calculating a second horizontal rotation angle such that the horizontal position of the plane orientation when the single crystal is rotated by the second rotation angle and then horizontally rotated by the second horizontal rotation angle is the same as the horizontal position of the target plane orientation when the single crystal is sliced, but the vertical position of the plane orientation when viewed from a direction orthogonal to the slice plane, coincides with the target plane orientation; a vertical rotation angle calculation step of calculating a vertical rotation angle such that the plane orientation when viewed from a direction orthogonal to the slice plane coincides with the target plane orientation when the single crystal is sliced, after being rotated by the second rotation angle, is vertically rotated about a horizontal axis;The single crystal is mounted on the slicing device and then rotated vertically by the vertical rotation angle so that the horizontal positions of the plane orientation and the target plane orientation when viewed from a direction perpendicular to the slicing plane are the same but different in vertical positions, and the second mounting step and the slicing step are performed.

[0013] (7) A notch formation position determining device of the present invention is a notch formation position determining device that determines notch formation positions in a single crystal used in manufacturing multiple wafers having notches, and includes: a positional relationship acquiring unit that acquires a positional relationship between multiple notch formation candidate positions identified based on the crystal orientation of the single crystal and a plane orientation of the single crystal; a correction amount calculating unit that calculates a first rotation angle such that, when the single crystal is rotated around a central axis of the single crystal from a state in which the notch formation candidate positions are located at a slice start position, the plane orientation and a target plane orientation are positioned in the same vertical direction when viewed from the central axis direction; and a notch formation position determining unit that determines, as the notch formation position, the notch formation candidate position such that the absolute value of the first rotation angle is equal to or greater than a specified angle.

[0014] (8) In the notch formation position determining device of the present invention, it is preferable that the specified angle is an acute angle, and the notch formation position determining unit determines the notch formation candidate position where the absolute value of the first rotation angle is 90° or less as the notch formation position.

[0015] (9) In the notch formation position determining device of the present invention, it is preferable that the correction amount calculation unit calculates a first horizontal rotation angle such that, when the single crystal is rotated by the first rotation angle and then rotated horizontally around a vertical axis, the plane orientation when viewed from a direction orthogonal to the slice plane that is orthogonal to the slice plane of the single crystal coincides with the target plane orientation, and when there are multiple notch formation candidate positions whose absolute values ​​of the first rotation angle are equal to or greater than the specified angle, the notch formation position determiner determines the notch formation candidate position with the smallest first horizontal rotation angle as the notch formation position.

[0016] (10) A notch forming device of the present invention includes any one of the notch forming position determining devices (7) to (9) and a notch forming section that forms the notch at the notch forming position.

[0017] (11) A wafer manufacturing system of the present invention includes the notch forming device of (10), a slicing device that produces the plurality of wafers by slicing the single crystal from the slicing start position, and a mounting device that mounts the single crystal on the slicing device so that the plane orientation when viewed from a direction perpendicular to the slicing plane that is perpendicular to the slicing plane of the single crystal coincides with the target plane orientation.

[0018] (12) A wafer manufacturing system of the present invention includes the notch formation position determining device of (9), a notch forming unit that forms the notch at the notch formation position, a slicing device that produces the plurality of wafers by slicing the single crystal from the slicing start position, a mounting device that mounts the single crystal on the slicing device, and a vertical rotation angle calculation unit, wherein the notch formation position determining unit, when there is no notch formation candidate position where the absolute value of the first rotation angle is equal to or greater than the specified angle, determines the notch formation candidate position where the absolute value of the first rotation angle is less than the specified angle. is determined as the notch formation position, and when the notch formation candidate position where the absolute value of the first rotation angle is equal to or greater than the specified angle is determined as the notch formation position, the mounting device mounts the single crystal to the slicing device based on the first rotation angle and the first horizontal rotation angle so that the plane orientation when viewed from a direction orthogonal to the slicing plane coincides with the target plane orientation, and the slicing device slices the single crystal mounted by the mounting device, and when the notch formation candidate position where the absolute value of the first rotation angle is less than the specified angle is determined as the notch formation position, When the notch formation position is determined as the slice start position, the correction amount calculation unit calculates a second rotation angle greater than the specified angle, and when the single crystal is rotated around the central axis in a state where the notch formation position is located at the slice start position, the plane orientation when viewed from the central axis direction and the position in the vertical direction of the target plane orientation become different, and when the single crystal rotated by the second rotation angle is horizontally rotated around the vertical axis, the plane orientation when viewed from a direction orthogonal to the slice plane and the position in the horizontal direction of the target plane orientation become the same, and the positions in the vertical direction become different. the vertical rotation angle calculation unit calculates a vertical rotation angle such that, when the single crystal is rotated by the second rotation angle and then horizontally rotated by the second horizontal rotation angle, the plane orientation when viewed from the direction orthogonal to the slicing plane coincides with the target plane orientation, and the mounting device calculates a vertical rotation angle such that, when the single crystal is rotated by the second rotation angle and then horizontally rotated by the second horizontal rotation angle, the plane orientation when viewed from the direction orthogonal to the slicing plane coincides with the target plane orientation in the horizontal direction, but the vertical positions of the plane orientation and the target plane orientation are different, based on the second rotation angle and the second horizontal rotation angle.The single crystal is attached to the slicing device, and the slicing device vertically rotates the single crystal attached by the attachment device by the vertical rotation angle and then slices it.

[0019] 12B is a schematic diagram showing the characteristics of a single crystal to be ground according to an embodiment; FIG. 12C is a schematic diagram showing the characteristics of a wafer produced from the single crystal to be ground according to an embodiment; FIG. 12D is a block diagram showing the general process of a wafer production system according to an embodiment; FIG. 12E is a plan view showing the general configuration of a cylindrical grinding apparatus according to an embodiment; FIG. 12F is a block diagram showing the configuration of a cylindrical grinding apparatus according to an embodiment; FIG. 12G is a block diagram showing the configuration of a mounting apparatus according to an embodiment; FIG. 12H is a block diagram showing the general configuration of a slicing apparatus according to an embodiment; FIG. 12H is a block diagram showing the configuration of a slicing apparatus according to an embodiment; FIG. 12H is a flowchart showing a wafer production method according to an embodiment; FIG. 12I is a flowchart showing a notch formation position determination process according to an embodiment; FIG. 12I is a flowchart showing a notch formation position determination process according to an embodiment; FIG. 12I is a schematic diagram showing a relationship between a first horizontal rotation angle and the size of an scrap according to an embodiment, showing a state in which the single crystal to be ground is horizontally rotated by the first horizontal rotation angle; FIG. 12I is a schematic diagram showing a relationship between a first horizontal rotation angle and the size of an scrap according to an embodiment, showing a state in which the single crystal to be ground is horizontally rotated by a first horizontal rotation angle that is larger than that of FIG. 12A; FIG. 12I is a flowchart showing a first mounting process according to an embodiment; FIG. 12I is a diagram showing a schematic diagram showing a process from the first mounting process or the second mounting process to the slicing process according to an embodiment. Fig. 1 is a flowchart showing a second mounting step according to an embodiment. Fig. 2 is a schematic diagram showing the characteristics of a single crystal to be ground according to a modified example, which shows the characteristics of a single crystal to be ground having a crystal central axis with a crystal orientation of <110>. Fig. 3 is a schematic diagram showing the characteristics of a single crystal to be ground according to a modified example, which shows the characteristics of a single crystal to be ground having a crystal central axis with a crystal orientation of <111>.

[0020] [Embodiment] An embodiment of the present invention will be described below. <Characteristics of the single crystal for grinding and wafer> First, the characteristics of the single crystal for grinding used in this embodiment and the wafers produced from the single crystal for grinding will be described. Fig. 1A is a schematic diagram showing the characteristics of the single crystal for grinding. Fig. 1B is a schematic diagram showing the characteristics of the wafers produced from the single crystal for grinding.

[0021] The single crystal to be ground T1 shown in FIG. 1A is obtained from a cylindrical silicon single crystal ingot T (see FIG. 2) manufactured by the Czochralski method or the like. The single crystal to be ground T1 is used to manufacture a single crystal to be sliced ​​T2 (see FIG. 2). The single crystal to be ground T1 may be composed of germanium, silicon carbide, gallium arsenide, indium arsenide, gallium nitride, aluminum nitride, or the like. The crystal orientation of the crystal center axis Ct of the single crystal to be ground T1 is <100>. On the outer peripheral surface of the single crystal to be ground T1, four crystal axes with a crystal orientation of <110> exist at 90° intervals in the circumferential direction. These four crystal axes are candidate positions Q for forming a notch N (hereinafter, sometimes referred to as "candidate notch formation positions Q"). If there are four candidate notch formation positions Q (hereinafter, each candidate notch formation position Q may be referred to as the "first candidate notch formation position Q1," the "second candidate notch formation position Q2," the "third candidate notch formation position Q3," and the "fourth candidate notch formation position Q4," respectively), there are four ways of expressing the plane orientation M of the single crystal to be ground T1 based on the candidate notch formation positions Q.

[0022] 1B is formed at one of four candidate notch formation positions Q. The notch N represents the surface orientation Mw of the wafer W obtained from the single crystal to be ground T1 (hereinafter, sometimes referred to as the "target surface orientation Mw"). The notch N is located at a position where the angle between an imaginary line connecting the notch N to the central axis Cw of the wafer W (hereinafter, sometimes referred to as the "wafer central axis Cw") and an imaginary line connecting the target surface orientation Mw and the wafer central axis Cw is a set angle α. The wafer W is produced by slicing the single crystal to be sliced ​​T2 such that the surface orientation M and the target surface orientation Mw coincide when viewed from a direction perpendicular to the slice surface of the single crystal to be sliced ​​T2 (hereinafter, sometimes referred to as the "direction perpendicular to the slice surface").

[0023] <General Process and Configuration of Wafer Manufacturing System> Next, a general process and configuration of a wafer manufacturing system used to manufacture wafers W will be described. FIG. 2 is a block diagram showing a general process of the wafer manufacturing system. FIG. 3 is a plan view showing a general configuration of a cylindrical grinding device. FIG. 4 is a block diagram showing a configuration of a cylindrical grinding device. FIG. 5 is a block diagram showing a configuration of a mounting device. FIG. 6 is a schematic diagram showing a general configuration of a slicing device. FIG. 7 is a block diagram showing a configuration of a slicing device.

[0024] 2 produces wafers W using silicon single crystal ingots T having a shoulder portion Ta, a body portion Tb, and a tail portion Tc. The wafer production system 1 includes a block processing device 2, a cylindrical grinding device 3, a mounting device 4, and a slicing device 5.

[0025] The block processing device 2 includes an outer peripheral grinding device 21 and a band saw 22. The outer peripheral grinding device 21 grinds the straight body portion Tb of the silicon single crystal ingot T into a cylindrical shape. The band saw 22 cuts a shoulder portion Ta and a tail portion Tc from the silicon single crystal ingot T ground by the outer peripheral grinding device 21, processing it into a single crystal to be ground T1 consisting of the straight body portion Tb. The cylindrical grinding device 3 cylindrically grinds the single crystal to be ground T1 while the crystal center axis Ct of the single crystal to be ground T1 and the rotation axis C (see FIG. 3 ) during cylindrical grinding are aligned on the same axis, thereby producing a single crystal to be sliced ​​T2. The cylindrical grinding device 3 also forms notches N in the single crystal to be sliced ​​T2. The single crystal to be sliced ​​T2 produced by the cylindrical grinding device 3 is cut by the band saw 22 into multiple blocks of a length that can be attached to the slicing device 5. If the length of the single crystal T2 to be sliced ​​is long enough to be attached to the slicing device 5, the band saw 22 does not have to cut the single crystal T2 to be sliced ​​into multiple blocks. The attachment device 4 attaches the single crystal T2 to the slicing device 5. The slicing device 5 is configured, for example, with a wire saw, and slices the single crystal T2 to be sliced ​​into multiple wafers W, each having a notch N. The wafer manufacturing system 1 may also cut the single crystal T1 to be ground into multiple blocks of a length that can be attached to the slicing device 5 using the band saw 22, and then perform the above-described processing on each block using the cylindrical grinding device 3, thereby manufacturing the single crystal T2 to be sliced ​​having a notch N.

[0026] 3 and 4, the cylindrical grinding device 3 includes a grinding unit 31, a first orientation measurement unit 32, a notch forming unit 33, and a control device 34. The positions of the components of the cylindrical grinding device 3 will be described with reference to the directions shown in FIG.

[0027] The grinding section 31 includes a first rotation processing section 311 , a grinding unit 312 , and a relative movement section 313 .

[0028] The first rotation processing section 311 holds the single crystal to be ground T1 and performs a rotation process by rotating it about a rotation axis C extending in the left-right direction. The first rotation processing section 311 includes a pair of rotation holding units 314 and a rotation holding unit moving section (not shown) that moves the pair of rotation holding units 314 toward or away from each other along the rotation axis C. Each rotation holding unit 314 includes a chuck 315 that holds an end of the single crystal to be ground T1 in the direction of the crystal central axis Ct, and a chuck driving section 316 that rotates the chuck 315 about the rotation axis C. The first rotation processing section 311 holds and rotates the single crystal to be ground T1 by the chuck 315 of each rotation holding unit 314 with its crystal central axis Ct aligned with the rotation axis C. The grinding unit 312 includes a grinding member 317 and a grinding member moving section 318 that moves the grinding member 317 toward or away from the single crystal to be ground T1. The grinding member 317 contacts a rear portion of the single crystal to be ground T1, which is rotated by the first rotation processing section 311, to grind the single crystal to be ground T1. The relative moving section 313 moves the grinding unit 312 along the rotation axis C relative to the rotation holding unit 314. By moving the grinding unit 312 along the rotation axis C while keeping the grinding member 317 in contact with the rotating single crystal to be ground T1, cylindrical grinding of the single crystal to be ground T1 can be performed. Note that when performing cylindrical grinding, the rotation holding unit 314 may be moved along the rotation axis C without moving the grinding unit 312, or both the grinding unit 312 and the rotation holding unit 314 may be moved along the rotation axis C.

[0029] The first orientation measurement unit 32 measures the plane orientation M and crystal axis of the single crystal to be ground T1 held by the first rotation processing unit 311. The first orientation measurement unit 32 includes an X-ray unit 321 that measures the plane orientation M and crystal axis, and an X-ray unit movement unit (not shown) that moves the X-ray unit 321 left and right in front of the single crystal to be ground T1 held by the rotation holding unit 314. The X-ray unit 321 measures the plane orientation M or crystal axis by irradiating X-rays, and outputs a signal representing the measurement result.

[0030] The notch forming section 33 forms a notch N in the single crystal to be sliced ​​T2.

[0031] The control device 34 includes an input unit 341 , a storage unit 342 , and a control unit 343 .

[0032] The input unit 341 is configured with, for example, a touch panel or physical buttons. The input unit 341 is used, for example, by an operator to input various settings related to the operation of the cylindrical grinding device 3, and outputs a signal corresponding to the input operation to the control unit 343.

[0033] The storage unit 342 stores various information related to the process of determining the position where the notch N will be formed (hereinafter, sometimes referred to as the "notch formation position") and the cylindrical grinding process in a manner readable by the control unit 343. Examples of the various information include the diameters and lengths of the single crystal to be ground T1 and the single crystal to be sliced ​​T2, the target plane orientation Mw, the positional relationship between the first, second, third, and fourth candidate notch formation positions Q1, Q2, Q3, and Q4 and the plane orientation M, the notch formation position, the specified angle β shown in Fig. 11, the first rotation angle φ1, and the first horizontal rotation angle θ1, and the additional angle φa, the second rotation angle φ2, and the second horizontal rotation angle θ2 shown in Fig. 14.

[0034] The control unit 343 includes a CPU, and realizes various functions by the CPU executing programs stored in the storage unit 342. The control unit 343 includes a positional relationship acquisition unit 344, a correction amount calculation unit 345, a notch formation position determination unit 346, a grinding control unit 347, and a notch formation control unit 348. The positional relationship acquisition unit 344, the correction amount calculation unit 345, and the notch formation position determination unit 346 constitute a notch formation position determination device. The notch formation position determination device, the notch forming unit 33, and the notch formation control unit 348 constitute a notch forming device.

[0035] The positional relationship acquisition unit 344 acquires the positional relationship between each candidate notch formation position Q and the plane orientation M of the single crystal to be ground T1. The correction amount calculation unit 345 calculates the first and second rotation angles φ1, φ2 and the first and second horizontal rotation angles θ1, θ2 of the single crystal to be sliced ​​T2 when manufacturing a wafer W using the single crystal to be sliced ​​T2. The notch formation position determination unit 346 determines one of the multiple candidate notch formation positions Q as the notch formation position based on the first rotation angle φ1, the first horizontal rotation angle θ1, and the specified angle β. The grinding control unit 347 controls the grinding unit 31 to rotate the single crystal to be ground T1 and moves the grinding member 317 along the rotation axis C while in contact with the single crystal to be ground T1, thereby performing cylindrical grinding. This cylindrical grinding yields a single crystal to be sliced ​​T2. The notch formation control unit 348 controls the notch forming unit 33 to form a notch N at the notch formation position on the outer peripheral surface of the single crystal to be sliced ​​T2.

[0036] <Configuration of Mounting Device> As shown in FIG. 5 , the mounting device 4 includes a second rotation processing unit 41, a second orientation measurement unit 42, a single crystal bonding processing unit 43, a horizontal rotation processing unit 44, a slicing table bonding processing unit 45, a mounting processing unit 46, and a control device 47. The second rotation processing unit 41 includes a pair of rollers 411 (see FIG. 14 ) arranged horizontally with their rotation axes parallel to each other. The single crystal T2 to be sliced ​​is placed on the pair of rollers 411 with the rotation axes of the pair of rollers 411 parallel to the crystal central axis Ct. The second rotation processing unit 41 rotates the pair of rollers 411 to rotate the single crystal T2 to be sliced ​​about the crystal central axis Ct. The second orientation measurement unit 42 includes an X-ray unit (not shown) that measures the plane orientation of the single crystal T2 to be sliced ​​on the pair of rollers 411 and outputs a signal representing the measurement result.

[0037] The single crystal bonding processor 43 bonds the single crystal T2 to be sliced ​​on the pair of rollers 411 of the second rotation processor 41 to the slicing table 532. The horizontal rotation processor 44 horizontally rotates the slicing table 532 to which the single crystal T2 to be sliced ​​is bonded, about a vertical axis D (see FIG. 11 ) that is perpendicular to and intersects with the central axis Ct. The slicing table bonding processor 45 bonds the slicing table 532, which has been horizontally rotated together with the single crystal T2 to be sliced ​​about the vertical axis D, to a work plate 531. The mounting processor 46 mounts the work plate 531 of the fixing member 53 to the mounting section 54 in a reference mounting state. The reference mounting state is a state in which the longitudinal direction of the work plate 531 of the fixing member 53 is parallel to the direction perpendicular to the slicing surface.

[0038] The control device 47 includes an input unit 471 , a storage unit 472 , and an attachment control unit 473 .

[0039] The input unit 471 has a configuration similar to that of the input unit 341 of the cylindrical grinding machine 3. The storage unit 472 stores various information related to the mounting process of the single crystal for slicing T2 so that the information can be read by the mounting control unit 473. The storage unit 472 stores, for example, the target plane orientation Mw, the positional relationship between the notch formation position and the plane orientation M determined by the control unit 343 of the cylindrical grinding machine 3, the first rotation angle φ1, the first horizontal rotation angle θ1, the second rotation angle φ2, and the second horizontal rotation angle θ2 based on input operations using the input unit 471.

[0040] The attachment control unit 473 includes a CPU, and realizes various functions by the CPU executing the programs stored in the storage unit 472. The attachment control unit 473 controls the second rotation processing unit 41, the second orientation measurement unit 42, the single crystal adhesion processing unit 43, the horizontal rotation processing unit 44, the slicing table adhesion processing unit 45, and the attachment processing unit 46 to attach the single crystal to be sliced ​​T2 to the slicing device 5.

[0041] <Configuration of Slicing Apparatus> As shown in FIGS. 6 and 7, the slicing apparatus 5 includes a slicing section 51, a lifting section 52, and a control device 57.

[0042] The slicing unit 51 includes three main rollers 511: two on the same horizontal plane and one below the two in the middle. The three main rollers 511 are arranged so that their rotation axes are parallel to each other and perpendicular to the vertical direction. Wires 512 are wound around the three main rollers 511 along their axial directions. By winding the wires 512 around the main rollers 511 in this manner, a wire array is formed between the two upper main rollers 511 (hereinafter sometimes referred to as the "upper main rollers 511A"), in which multiple wires 512 are arranged at a constant pitch along the axial direction of the main rollers 511. The direction in which the wires 512 are arranged in the wire array is parallel to the direction perpendicular to the slicing surface. Wire reels 514 and 515 are arranged on both ends of the wire 512, which feed and rewind the wire 512 via guide rollers 513. Above the upper main rollers 511A, nozzles 516 for supplying slurry G are disposed at intermediate positions between the two upper main rollers 511A.

[0043] The lifting unit 52 raises and lowers the single crystal T2 above the nozzle 516 relative to the wire 512. The lifting unit 52 includes a fixing member 53, an attachment unit 54, a vertical rotation processing unit 55, and an elevation drive unit 56. The fixing member 53 includes a rectangular work plate 531 held by the attachment unit 54 and a slicing table 532 bonded to the work plate 531. The slicing table 532 is a substantially rectangular plate-shaped member and is cut together with the single crystal T2 by the wire 512. The slicing table 532 includes an arc-shaped fixing surface 532A to which the single crystal T2 is fixed via adhesive. The single crystal T2 is fixed to the fixing surface 532A with the longitudinal direction of the slicing table 532 parallel to the crystal central axis Ct of the single crystal T2. The slicing table 532 has a flat surface opposite to the fixed surface 532A adhered to the work plate 531.

[0044] The mounting unit 54 includes, for example, a holding mechanism for holding a work plate 531. The work plate 531 of the fixed member 53 is attached to the mounting unit 54. The vertical rotation processing unit 55 vertically rotates the mounting unit 54 around a horizontal axis E that is perpendicular to the direction orthogonal to the slice plane and the vertical direction. The elevation drive unit 56 raises and lowers the mounting unit 54 and the vertical rotation processing unit 55.

[0045] The control device 57 includes an input unit 571 , a storage unit 572 , and a control unit 573 .

[0046] The input unit 571 has a configuration similar to that of the input unit 341 of the cylindrical grinding machine 3. The storage unit 572 stores various types of information related to the slicing process so that the information can be read by the attachment control unit 473. An example of the various types of information is the vertical rotation angle λ shown in FIG. 14. The storage unit 572 also stores, for example, the target surface orientation Mw, the positional relationship between the notch formation position and the surface orientation M determined by the control unit 343 of the cylindrical grinding machine 3, the second rotation angle φ2, and the second horizontal rotation angle θ2 based on input operations using the input unit 571.

[0047] The control unit 573 includes a CPU, and realizes various functions by the CPU executing programs stored in the storage unit 572. The control unit 573 includes a vertical rotation angle calculation unit 574 and a slice control unit 575.

[0048] The vertical rotation angle calculation unit 574 calculates the vertical rotation angle λ. The slice control unit 575 controls the slicing unit 51 and the lifting unit 52 to produce a plurality of wafers W from the single crystal to be sliced ​​T2.

[0049] The slicing device 5 having the above configuration rotates the multiple main rollers 511 to run the wire 512 in a direction (left-right direction) substantially perpendicular to the axial direction of the main rollers 511, and while supplying slurry G between the two upper main rollers 511A, lowers the single crystal to be sliced ​​T2 and presses it against the wire row, slicing the single crystal to be sliced ​​T2 to produce multiple wafers W. The slicing device 5 may be configured so that slicing begins from the upper end of the single crystal to be sliced ​​T2 when viewed from the direction perpendicular to the slicing surface.

[0050] <Wafer Manufacturing Method> Next, a method for manufacturing a wafer W using the wafer manufacturing system 1 will be described. FIG. 8 is a flowchart illustrating a wafer manufacturing method. FIGS. 9 and 10 are flowcharts illustrating a notch formation position determining step. FIG. 11 is an explanatory diagram illustrating a schematic diagram of the notch formation position determining step. FIG. 12 is a schematic diagram illustrating the relationship between the first horizontal rotation angle and the size of the scrap material, where (A) shows a state in which the single crystal for slicing has been horizontally rotated by the first horizontal rotation angle, and (B) shows a state in which the single crystal for slicing has been horizontally rotated by a first horizontal rotation angle greater than that of (A). FIG. 13 is a flowchart illustrating a first mounting step. FIG. 14 is an explanatory diagram illustrating a schematic diagram of the steps from the first mounting step or the second mounting step to the slicing step. FIG. 15 is a flowchart illustrating a second mounting step.

[0051] A working device (not shown) or an operator holds the cylindrical single crystal to be ground T1 obtained by processing with the block processing device 2 in the rotation holding unit 314 of the cylindrical grinding device 3 with the crystal central axis Ct aligned with the rotation axis C. Next, as shown in Fig. 8, the control unit 343 of the cylindrical grinding device 3 determines a notch formation position from a plurality of candidate notch formation positions Q (step S1: notch formation position determination step). The notch formation position determination step of step S1 includes the processes of steps S11 to S20 shown in Figs. 9 and 10.

[0052] First, the positional relationship acquisition unit 344 of the control unit 343 acquires the positional relationship between each notch formation candidate position Q and the plane orientation M of the single crystal to be ground T1 (step S11: positional relationship acquisition step). In step S11, the positional relationship acquisition unit 344 controls the chuck driver 316 to rotate the single crystal to be ground T1, while controlling the first orientation measurement unit 32 to acquire measurement results for all crystal axes present in the single crystal to be ground T1. The positional relationship acquisition unit 344 sets the nth (n is a natural number) measured crystal axis as the nth notch formation candidate position Qn. The positional relationship acquisition unit 344 controls the chuck driver 316 to rotate the single crystal to be ground T1, and stops it in an orientation where the first notch formation candidate position Q1 is at its highest position. The positional relationship acquisition unit 344 controls the first orientation measurement unit 32 to acquire the measurement results of the positional relationship between the first notch formation candidate position Q1 and the surface orientation M, as shown in the first diagram from the left in the top row of Fig. 11. The positional relationship acquisition unit 344 performs similar processing for each of the other notch formation candidate positions Q, and acquires the measurement results of the positional relationship between each of the notch formation candidate positions Q and the surface orientation M, as shown in each diagram in the top row of Fig. 11.

[0053] The correction amount calculation unit 345 calculates the first rotation angle φ1 corresponding to each notch formation candidate position Q (step S12: first rotation angle calculation step). In step S12, when the slicing single crystal T2 is rotated from a state in which the first notch formation candidate position Q1 is located at the slicing start position P when viewed from the crystal central axis Ct direction, the correction amount calculation unit 345 calculates, as the first rotation angle φ1 corresponding to the first notch formation candidate position Q1, an angle that can align the vertical positions of the plane orientation M when viewed from the crystal central axis Ct direction with the target plane orientation Mw, as shown in the first left diagram in the lower part of FIG. 11 . The correction amount calculation unit 345 performs the same process for each of the other notch formation candidate positions Q, and calculates the first rotation angle φ1 corresponding to each notch formation candidate position Q as shown in each diagram in the lower part of FIG.

[0054] The correction amount calculation unit 345 calculates a first horizontal rotation angle θ1 corresponding to each notch formation candidate position Q (step S13: first horizontal rotation angle calculation step). In step S13, the correction amount calculation unit 345 calculates, as the first horizontal rotation angle θ1 corresponding to the first notch formation candidate position Q1, an angle at which the plane orientation M, as viewed from the direction perpendicular to the slicing plane, and the target plane orientation Mw can be aligned when the single crystal to be sliced ​​T2, which has been rotated by the first rotation angle φ1, is horizontally rotated about the vertical axis D, as shown in the first diagram from the left in the lower part of FIG. 11 . The correction amount calculation unit 345 performs similar processing for each of the other notch formation candidate positions Q, and calculates the first horizontal rotation angle θ1 corresponding to each of the notch formation candidate positions Q as shown in the diagrams in the lower part of FIG. 11 .

[0055] The notch formation position determining unit 346 determines whether there is a notch formation candidate position Q where the absolute value of the first rotation angle φ1 is greater than or equal to the specified angle β and less than or equal to 90° (step S14). The specified angle β is set for the following reason: When the slicing device 5 cuts the single crystal T2 to be sliced, if the circumferential distance from the slicing start position P to the notch N is too short, damage may occur around the notch N. If a damaged wafer W is subjected to heat treatment, for example, for device fabrication, the damage may serve as a starting point for slip dislocation, which may affect the device manufacturing yield. The specified angle β is set to an angle that can prevent such damage from occurring. Examples of the specified angle β include an angle between 30° and 45°. The specified angle β used in the notch formation position determining step may be the same regardless of the diameter of the single crystal T2 to be sliced, or it may vary depending on the diameter of the single crystal T2 to be sliced.

[0056] If the notch formation position determiner 346 determines in step S14 that a notch formation candidate position Q exists where the absolute value of the first rotation angle φ1 is greater than or equal to the specified angle β and less than or equal to 90° (step S14: YES), it determines whether or not multiple notch formation candidate positions Q exist that satisfy the determination criterion of step S14 (where the absolute value of the first rotation angle φ1 is greater than or equal to the specified angle β and less than or equal to 90°) (step S15). If the notch formation position determiner 346 determines in step S15 that multiple notch formation candidate positions Q exist that satisfy the determination criterion of step S14 (step S15: YES), it performs a first determination step (step S16). In step S16, the notch formation position determiner 346 determines the notch formation candidate position Q that satisfies the determination criterion of step S14 and has the smallest first horizontal rotation angle θ1 as the notch formation position. The reason for determining the notch formation position through the first determination step of step S16 will be described. As shown in Fig. 12A, when a single crystal T2 for slicing, whose crystal central axis Ct is parallel to the direction orthogonal to the slicing plane, is horizontally rotated by a first horizontal rotation angle θ11 before producing wafers W, both ends of the single crystal T2 for slicing, indicated by the shaded areas, become scrap Te from which wafers W cannot be obtained. As shown in Fig. 12B, when the single crystal T2 for slicing is horizontally rotated by a first horizontal rotation angle θ12 that is larger than the first horizontal rotation angle θ11, the scrap Te becomes larger than when the single crystal T2 is horizontally rotated by the first horizontal rotation angle θ11. To further reduce the size of such scrap Te, a notch formation position is determined in the first determination process of step S16.

[0057] If it is determined in step S15 that there are no notch formation candidate positions Q that satisfy the criteria of step S14 (step S15: NO), the notch formation position determiner 346 performs a second determination step (step S17). In step S17, the notch formation position determiner 346 determines the only notch formation candidate position Q that satisfies the criteria of step S14 as the notch formation position.

[0058] In step S14, if the notch formation position determiner 346 determines that there is no notch formation candidate position Q for which the absolute value of the first rotation angle φ1 is equal to or greater than the specified angle β and less than 90°, that is, the absolute values ​​of the first rotation angles φ1 corresponding to all of the notch formation candidate positions Q are less than the specified angle β (step S14: NO), the notch formation position determiner 346 performs a third determination step (step S18) as shown in Fig. 10. In step S18, the notch formation position determiner 346 determines, as the notch formation position, the notch formation candidate position Q for which the absolute value of the first rotation angle φ1 is less than the specified angle β and the first horizontal rotation angle θ1 is the smallest.

[0059] The correction amount calculation unit 345 calculates a second rotation angle φ2 corresponding to the notch formation position determined in the third determination step (step S19: second rotation angle calculation step). In step S19, the correction amount calculation unit 345 uses the specified angle β as the additional angle φa and calculates the second rotation angle φ2 as the angle obtained by adding the additional angle φa to the first rotation angle φ1, i.e., an angle equal to or greater than the specified angle, as shown in the second diagram from the left in the lower part of FIG. 14 . When a notch N is formed at the notch formation position determined in the third determination step, by rotating the single crystal T2 to be sliced ​​by the second rotation angle φ2 around the crystal central axis Ct from a state in which the notch N is located at the slicing start position P, the vertical positions of the crystal plane orientation M and the target crystal plane orientation Mw will differ regardless of the magnitude of the first rotation angle φ1. The correction amount calculation unit 345 may calculate a predetermined specific angle that is larger than the specified angle β as the second rotation angle φ2.

[0060] The correction amount calculation unit 345 calculates a second horizontal rotation angle θ2 corresponding to the notch formation position determined in the third determination step (step S20: second horizontal rotation angle calculation step). In step S20, the correction amount calculation unit 345 calculates, as the second horizontal rotation angle θ2, an angle at which the plane orientation M and the target plane orientation Mw can be aligned in the horizontal direction when viewed from the direction perpendicular to the slicing plane, as shown in the third diagram from the left in the bottom row of FIG. 14 , when the single crystal T2 for slicing, with the notch N located at the slicing start position P, is rotated by the second rotation angle φ2 and then horizontally rotated about the vertical axis D. When the single crystal T2 for slicing, with the notch N located at the slicing start position P, is rotated by the second rotation angle φ2 and then horizontally rotated by the second horizontal rotation angle θ2, the plane orientation M and the target plane orientation Mw will be aligned in the vertical direction when viewed from the direction perpendicular to the slicing plane.

[0061] 11 , it is determined in step S14 that the absolute values ​​of the first rotation angles φ1 corresponding to the second and third notch formation candidate positions Q2 and Q3 are not equal to or greater than the specified angle β and not equal to or less than 90°. On the other hand, it is determined in step S14 that the absolute values ​​of the first rotation angles φ1 corresponding to the first and fourth notch formation candidate positions Q1 and Q4 are not equal to or greater than the specified angle β and not equal to or less than 90°. Then, in the first determination step of step S16, the first notch formation candidate position Q1, which has the smaller first horizontal rotation angle θ1, is determined as the notch formation position from among the first and fourth notch formation candidate positions Q1 and Q4.

[0062] As shown in FIG. 8, after the notch formation position determination process of step S1 is completed, the grinding control unit 347 controls the grinding unit 31 to cylindrically grind the single crystal to be ground T1 to process it into a single crystal to be sliced ​​T2 (step S2: cylindrical grinding process).

[0063] Next, the notch formation control unit 348 forms a notch N at the notch formation position determined in the first determination step of step S16, the second determination step of step S17, or the third determination step of step S18 (step S3: notch formation step). In step S3, the notch formation control unit 348 controls the chuck driving unit 316 to rotate the single crystal to be sliced ​​T2 and stops it in a state where the notch N can be formed at the notch formation position by the notch forming unit 33. The notch formation control unit 348 controls the notch forming unit 33 to form the notch N at the notch formation position.

[0064] Thereafter, the attachment control unit 473 of the attachment device 4 determines whether the absolute value of the first rotation angle φ1 corresponding to the notch formation position is equal to or greater than the specified angle β (step S4). In step S4, if the attachment control unit 473 determines that the absolute value of the first rotation angle φ1 corresponding to the notch formation position is equal to or greater than the specified angle β (step S4: YES), the attachment control unit 473 performs a first attachment step (step S5). The first attachment step in step S5 includes the processes of steps S51 to S56 shown in FIG.

[0065] In the first mounting step, which is performed when the absolute value of the first rotation angle φ1 is equal to or greater than the specified angle β, the mounting control unit 473 measures the plane orientation M of the single crystal for slicing T2 (step S51: first plane orientation measurement step). In step S51, when the single crystal for slicing T2 is placed on the pair of rollers 411 of the second rotation processing unit 41, the mounting control unit 473 controls the second rotation processing unit 41 to rotate the single crystal for slicing T2 so that the notch N is located at the highest position, i.e., the notch N is located at the slicing start position P, as shown in the first diagram from the left in the upper row of Figure 14. The mounting control unit 473 controls the second orientation measurement unit 42 to measure the plane orientation M of the single crystal for slicing T2.

[0066] The attachment control unit 473 controls the second rotation processing unit 41 to rotate the single crystal for slicing T2 by the first rotation angle φ1 (step S52: first single crystal rotation step), as shown in the second diagram from the left in the top row of Fig. 14. The attachment control unit 473 controls the single crystal bonding processing unit 43 to bond the single crystal for slicing T2 to the slicing table 532 (step S53: first single crystal bonding step).

[0067] The attachment control unit 473 controls the horizontal rotation processing unit 44 to horizontally rotate the slicing table 532 by a first horizontal rotation angle θ1 from a state in which the longitudinal direction of the work plate 531 and the longitudinal direction of the slicing table 532 are parallel, as shown in the third diagram from the left in the upper row of FIG. 14 (step S54: first single crystal horizontal rotation step). The attachment control unit 473 controls the slicing table bonding processing unit 45 to bond the slicing table 532 to the work plate 531 (step S55: first slicing table bonding step). The attachment control unit 473 controls the attachment processing unit 46 to attach the work plate 531 of the fixing member 53 to the attachment unit 54 of the slicing device 5 in a standard attachment state, as shown in the fourth diagram from the left (second diagram from the right) in the upper row of FIG. 14 (step S56: first fixing member attachment step). At this time, the slicing control unit 575 of the slicing device 5 may control the attachment unit 54 so that the work plate 531 is attached.

[0068] By the first mounting step including the above steps S51 to S56, the single crystal T2 to be sliced ​​is mounted on the slicing device 5 in such a state that, when viewed from the direction perpendicular to the slicing plane, the rotation angle from the slicing start position P is equal to or greater than the specified angle β and the plane orientation M coincides with the target plane orientation Mw. Note that at least one of the steps S51, in which the single crystal T2 to be sliced ​​is rotated, and the steps S52 to S56 may be performed by an operator.

[0069] 8, after the first mounting step of step S5 is completed, the slice control unit 575 of the slicer 5 controls the slicer 51 and the lifting / lowering unit 56 to slice the single crystal T2 starting from the slice start position P (step S6: slice step). The slice step of step S6 produces a plurality of wafers W whose plane orientations M match the target plane orientation Mw and whose plane orientations M and notches N have a specific relationship, as shown in the fifth diagram from the left (first diagram from the right) in the top row of FIG.

[0070] On the other hand, if the attachment control unit 473 determines in step S4 that the absolute value of the first rotation angle φ1 corresponding to the notch formation position is not equal to or greater than the specified angle β (step S4: NO), the attachment control unit 473 performs a second attachment process (step S7). The second attachment process in step S7 includes the processes of steps S71 to S78 shown in FIG.

[0071] In the second mounting step, which is performed when the absolute value of the first rotation angle φ1 is less than the specified angle β, the mounting control unit 473 rotates the single crystal T2 to be sliced ​​so that the notch N is located at the slicing start position P, as shown in the first diagram from the left in the lower row of Figure 14, and measures the crystal plane orientation M (step S71: second crystal plane orientation measurement step), similar to step S51 in the first mounting step.

[0072] The attachment control unit 473 controls the second rotation processing unit 41 to rotate the single crystal T2 for slicing by a second rotation angle φ2 larger than the first rotation angle φ1, as shown in the second diagram from the left in the bottom row of Fig. 14 (step S72: second single crystal rotation step).The attachment control unit 473 controls the single crystal bonding processing unit 43 to bond the single crystal T2 for slicing to the slicing table 532 (step S73: second single crystal bonding step).

[0073] The attachment control unit 473 controls the horizontal rotation processing unit 44 to horizontally rotate the slicing table 532 by a second horizontal rotation angle θ2 from a state in which the longitudinal direction of the work plate 531 and the longitudinal direction of the slicing table 532 are parallel, as shown in the third diagram from the left in the bottom row of FIG. 14 (step S74: second single crystal horizontal rotation step). The attachment control unit 473 controls the slicing table bonding processing unit 45 to bond the slicing table 532 to the work plate 531 (step S75: second slicing table bonding step). The attachment control unit 473 controls the attachment processing unit 46 to attach the work plate 531 of the fixing member 53 to the attachment unit 54 of the slicing device 5 in the reference attachment state, as shown in the fourth diagram from the left (second diagram from the right) in the bottom row of FIG. 14 (step S76: second fixing member attachment step). At this time, the slicing control unit 575 of the slicing device 5 may control the attachment unit 54 so that the work plate 531 is attached.

[0074] Through the above steps S71 to S76, the single crystal T2 to be sliced ​​is attached to the slicing device 5 in such a state that its rotation angle from the slicing start position P is equal to or greater than the specified angle β, the horizontal positions of the plane orientation M and the target plane orientation Mw are the same, and their vertical positions are different.

[0075] The vertical rotation angle calculation unit 574 calculates the vertical rotation angle λ corresponding to the notch formation position determined in the third determination step (step S77: vertical rotation angle calculation step). In step S77, the vertical rotation angle calculation unit 574 calculates the vertical rotation angle λ as the angle at which the plane orientation M and the target plane orientation Mw can be aligned in the vertical direction when viewed from the direction perpendicular to the slicing plane, as shown in the fifth diagram from the left (first diagram from the right) in the bottom row of Figure 14, when the single crystal T2 to be sliced, with the notch N located at the slicing start position P, is rotated by the second rotation angle φ2, then horizontally rotated by the second horizontal rotation angle θ2, and then vertically rotated about the horizontal axis E. The vertical rotation angle λ is the angle at which the plane orientation M and the target plane orientation Mw can be aligned in the vertical direction when viewed from the direction perpendicular to the slicing plane, as shown in the fifth diagram from the left (first diagram from the right) in the bottom row of Figure 14. Note that the vertical rotation angle calculation step may be performed at any timing after the second horizontal rotation angle calculation step.

[0076] As shown in the fifth diagram from the left (first diagram from the right) in the bottom row of Fig. 14, the slicing control unit 575 controls the vertical rotation processing unit 55 to vertically rotate the mounting unit 54 by a vertical rotation angle λ (step S78: single crystal vertical rotation step). Even if a notch N is formed at a notch formation position where the absolute value of the first rotation angle φ1 is less than the specified angle β through the step S78, the single crystal T2 to be sliced ​​will have a rotation angle from the slicing start position P equal to or greater than the specified angle β when viewed from the direction perpendicular to the slicing plane, and the crystal plane orientation M will coincide with the target crystal plane orientation Mw. Note that the step of rotating the single crystal T2 to be sliced ​​in step S71 and at least one of steps S72 to S78 may be performed by an operator.

[0077] 8, after the second mounting step in step S7 is completed, the slice control unit 575 performs the slicing step in step S6. As in the case where the slicing step is performed after the first mounting step in step S5, the slicing step in step S6 produces a plurality of wafers W whose surface orientations M match the target surface orientations Mw and whose surface orientations M and notches N have a specific relationship, as shown in the fifth diagram from the left (first diagram from the right) in the top row of FIG.

[0078] By the above processing of steps S1 to S7, a plurality of wafers W are obtained in which the surface orientation M coincides with the target surface orientation Mw and the surface orientation M and the notch N have a specific relationship, regardless of the magnitude of the first rotation angle φ1. Wafers W obtained in this manner have undulations perpendicular to the slicing direction. From this undulation, the slicing direction can be estimated, and the positional relationship between the notch N and the slicing start position P can be estimated.

[0079] [Effects of the embodiment] When slicing the single crystal T2 to be sliced ​​so that the plane orientation M coincides with the target plane orientation Mw, the notch formation position determiner 346 determines, as the notch formation position, a candidate notch formation position Q at which the absolute value of the first rotation angle φ1 is equal to or greater than the specified angle β. This makes it possible to prevent damage to the wafer W when slicing the single crystal T2 to be sliced.

[0080] The notch formation position determining unit 346 determines, as the notch formation position, a candidate notch formation position Q where the absolute value of the first rotation angle φ1 is equal to or larger than the specified angle β and is equal to or smaller than 90°. This prevents the time required for the rotation of the single crystal T2 for slicing when the single crystal T2 for slicing is attached to the slicing device 5 from becoming long.

[0081] [Modifications] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and various improvements and design changes that do not deviate from the gist of the present invention are also included in the present invention.

[0082] A notch formation candidate position Q where the first rotation angle φ1 exceeds 90° may be determined as the notch formation position. Among multiple notch formation candidate positions Q where the first rotation angle φ1 is equal to or greater than a specified angle β, a notch formation candidate position Q where the first horizontal rotation angle θ1 is not the smallest may be determined as the notch formation position. If the absolute values ​​of the first rotation angles φ1 corresponding to all of the notch formation candidate positions Q are less than the specified angle β, a notch formation candidate position Q where the first horizontal rotation angle θ1 is not the smallest may be determined as the notch formation position. If the absolute values ​​of the first rotation angles φ1 corresponding to all of the notch formation candidate positions Q are less than the specified angle β, no notch formation position may be determined, and the single crystal to be ground T1 need not be used for manufacturing wafers W.

[0083] If the correction amount calculation unit 345 determines that the plane orientation M when viewed from the direction of the crystal central axis Ct matches the target plane orientation Mw when the predetermined candidate notch formation position Q is rotated by the first rotation angle φ1 from a state in which the predetermined candidate notch formation position Q is located at the slicing start position P, it is not necessary to calculate the first horizontal rotation angle θ1 of the predetermined candidate notch formation position Q. When a notch N is formed at the predetermined candidate notch formation position Q, the slicing table 532 to which the single crystal T2 to be sliced ​​is adhered to the work plate 531 with the longitudinal direction of the slicing table 532 parallel to the longitudinal direction of the work plate 531, and the work plate 531 is attached to the slicing device 5 in the reference attachment state before slicing the single crystal T2 to be sliced.

[0084] The notch formation position determining step S1 may be performed after the cylindrical grinding step S2. Although the cylindrical grinding device 3, the mounting device 4, and the slicing device 5 are respectively equipped with the control devices 34, 47, and 57 in the above example, a control device that controls the cylindrical grinding device 3, the mounting device 4, and the slicing device 5 collectively may be provided.

[0085] In the above embodiment, a method for manufacturing a wafer W using a single crystal to be ground T1 having a crystallographic orientation of the crystal central axis Ct of <100> has been described. However, a wafer W may also be manufactured using a single crystal to be ground T1 having a crystallographic orientation of the crystal central axis Ct of <110> as shown in FIG. 16A or a single crystal to be ground T1 having a crystallographic orientation of the crystal central axis Ct of <111> as shown in FIG. 16B. When the single crystal to be ground T1 shown in FIG. 16A is used, two crystal axes having a crystallographic orientation of <110>, i.e., two candidate notch formation positions Q (a first candidate notch formation position Q1 and a second candidate notch formation position Q2) are present on the outer peripheral surface of the single crystal to be ground T1 at 180° intervals in the circumferential direction. Then, the first candidate notch formation position Q1 or the second candidate notch formation position Q2 is determined as the notch formation position by the notch formation position determination step shown in FIG. 9. 16B is used, three crystal axes with a crystal orientation <111>, i.e., three candidate notch formation positions Q (first candidate notch formation position Q1, second candidate notch formation position Q2, and third candidate notch formation position Q3) exist on the outer peripheral surface of the single crystal to be ground T1 at 120° intervals in the circumferential direction. Then, by the notch formation position determination step shown in FIG. 9, any one of the first to third candidate notch formation positions Q1 to Q3 is determined as the notch formation position.

[0086] Next, examples of the present invention will be described, but the present invention is not limited to these examples.

[0087] As an example, a simulation was performed to confirm whether or not the single crystal T2 to be sliced ​​can be sliced ​​so as to obtain a plurality of wafers W whose surface orientation M matches the target surface orientation Mw while suppressing damage to the periphery of the notch N, when the notch formation position of the single crystal T2 to be sliced ​​having an arbitrary surface orientation M is determined using the method for determining the notch formation position of the present invention or the method for determining the notch formation position of the comparative example.

[0088] [Simulation Method of Comparative Example] First, the simulation method of the comparative example will be described. In the simulation of the comparative example, various conditions were set as follows: Diameter of the single crystal to be sliced ​​T2: 301 mm Crystal orientation of the crystal central axis Ct: <100> Target plane orientation Mw: X = 0.25°, Y = 0.00° The X direction representing the target plane orientation Mw is the horizontal direction, and the Y direction is the vertical direction. In addition, a method for determining the notch formation position of the comparative example was set. The method for determining the notch formation position of the comparative example involves rotating the single crystal to be sliced ​​T2 by a process similar to step S11 of the above embodiment, determining the first measured crystal axis among multiple crystal axes present in the single crystal to be sliced ​​T2 as the notch formation position, and obtaining the positional relationship between the notch formation position and the plane orientation M.

[0089] Then, 2881 single crystals to be sliced ​​T2, each having different values ​​of at least one of the horizontal (X direction) and vertical (Y direction) plane orientations based on the crystal central axis Ct as viewed from the direction of the crystal central axis Ct, were subjected to processing based on the comparative example method for determining the notch formation position to obtain the positional relationship between the notch formation position and the plane orientation M. Furthermore, a first rotation angle φ1 corresponding to the notch formation position was calculated based on the plane orientation M and the target plane orientation Mw.

[0090] [Simulation Method of the Example] Next, a simulation method of the Example will be described. In the simulation of the Example, the diameter of the single crystal to be sliced ​​T2, the crystal orientation of the crystal central axis Ct, and the target plane orientation Mw were set to the same values ​​as those in the comparative example, and the specified angle β was set as follows: Specified angle β: 45°. Furthermore, the method of determining the notch formation position by the first determination step of step S16 or the second determination step of step S17 in the notch formation position determination step of step S1 shown in Figure 8, i.e., the notch formation position determination method of the present invention, was set as the notch formation position determination method of the Example.

[0091] Then, the same 2,881 slice-forming single crystals T2 as in the comparative example were subjected to processing based on the method for determining the notch formation position of the embodiment, and one of the multiple notch formation candidate positions present in the slice-forming single crystal T2 was determined as the notch formation position, and the first rotation angle φ1 corresponding to the notch formation position was calculated.

[0092] [Simulation Results and Discussion] The single crystals T2 for slicing whose first rotation angle φ1 corresponding to the notch formation position was equal to or greater than the specified angle β were evaluated as acceptable, and the single crystals T2 for slicing whose first rotation angle φ1 was less than the specified angle β were evaluated as unacceptable. The method for determining the notch formation position of the comparative example yielded a pass rate of 57.7% (1,663 accepted products), while the method for determining the notch formation position of the example yielded a pass rate of 91.1% (2,626 accepted products). From the above, it was confirmed that when the method for determining the notch formation position of the single crystal T2 for slicing having an arbitrary crystal plane orientation M is used to determine the notch formation position, the single crystal T2 for slicing can be sliced ​​to obtain multiple wafers W whose crystal plane orientation M matches the target crystal plane orientation Mw while suppressing damage to the periphery of the notch N.

[0093] 1...wafer manufacturing system, 4...mounting device, 5...slicing device, 33...notch forming unit (notch forming device), 344...positional relationship acquisition unit (notch forming position determining device, notch forming device), 345...correction amount calculation unit (notch forming position determining device, notch forming device), 346...notch forming position determining unit (notch forming position determining device, notch forming device), 348...notch formation control unit (notch forming device), 574...vertical rotation angle calculation unit calculation unit, D...vertical axis, E...horizontal axis, M...plane orientation, Mw...target plane orientation, N...notch, P...slicing start position, Q...candidate position for notch formation, Q1 to Q4...first to fourth candidate positions for notch formation, T1...single crystal to be ground, T2...single crystal to be sliced, W...wafer, β...specified angle, θ1, θ11, θ12...first horizontal rotation angle, θ2...second horizontal rotation angle, λ...vertical rotation angle, φ1...first rotation angle, φ2...second rotation angle.

Claims

1. A method for determining a notch formation position in a single crystal used in the manufacture of multiple wafers having notches, comprising: a positional relationship acquisition step of acquiring a positional relationship between a plurality of candidate notch formation positions identified based on the crystal orientation of the single crystal and a plane orientation of the single crystal; a first rotation angle calculation step of calculating a first rotation angle such that, when the single crystal is rotated around the central axis of the single crystal from a state in which the candidate notch formation positions are located at a slice start position, the plane orientation and a target plane orientation are positioned in the same vertical direction as viewed from the central axis direction; and a determination step of determining, as the notch formation position, the candidate notch formation position such that the absolute value of the first rotation angle is equal to or greater than a specified angle.

2. A method for determining a notch formation position according to claim 1, wherein the specified angle is an acute angle, and the determination step determines, as the notch formation position, the candidate notch formation position for which the absolute value of the first rotation angle is 90° or less.

3. A method for determining a notch formation position as set forth in claim 1, comprising a first horizontal rotation angle calculation step of calculating a first horizontal rotation angle such that, when the single crystal is rotated by the first rotation angle and then rotated horizontally around a vertical axis, the plane orientation when viewed from a direction orthogonal to the slice plane orthogonal to the slice plane of the single crystal coincides with the target plane orientation, and wherein, when there are multiple candidate notch formation positions whose absolute value of the first rotation angle is equal to or greater than the specified angle, the candidate notch formation position with the smallest first horizontal rotation angle is determined as the notch formation position.

4. A notch formation method comprising: a notch formation position determination step of determining the notch formation position by the notch formation position determination method described in any one of claims 1 to 3; and a notch formation step of forming the notch at the notch formation position.

5. A method for manufacturing wafers, comprising: a step of forming a notch in the single crystal by the notch forming method set forth in claim 4; a mounting step of mounting the single crystal on a slicing device so that the plane orientation when viewed from a direction perpendicular to the slicing plane perpendicular to the slicing plane of the single crystal coincides with the target plane orientation; and a slicing step of manufacturing the plurality of wafers by slicing the single crystal from the slicing start position using the slicing device.

6. A method of manufacturing a wafer, comprising: a notch formation position determining step of determining the notch formation position by the notch formation position determining method of claim 3; a notch formation step of forming the notch at the notch formation position; a first mounting step and a second mounting step of mounting the single crystal to a slicing device; and a slicing step of manufacturing the plurality of wafers by slicing the single crystal from the slicing start position with the slicing device, wherein the determining step, if there is no notch formation candidate position where the absolute value of the first rotation angle is equal to or greater than the specified angle, determines the notch formation candidate position where the absolute value of the first rotation angle is less than the specified angle as the notch formation position; and, if the notch formation candidate position where the absolute value of the first rotation angle is equal to or greater than the specified angle is determined as the notch formation position, performs the notch formation step; the first mounting step of mounting the single crystal to the slicing device based on the first rotation angle and the first horizontal rotation angle so that the plane orientation when viewed from a direction perpendicular to the slicing plane coincides with the target plane orientation; and the slicing step, when the notch formation candidate position, the absolute value of which is less than the specified angle, is determined as the notch formation position, a second rotation angle calculation step of calculating a second rotation angle greater than the specified angle when the single crystal is rotated about the central axis in a state where the notch formation position is located at the slice start position, such that the plane orientation when viewed from the central axis direction and the vertical position of the target plane orientation differ, and the second rotation angle is greater than the specified angle; and a second horizontal rotation angle calculation step of calculating a second horizontal rotation angle when the single crystal rotated by the second rotation angle is horizontally rotated about the vertical axis such that the plane orientation when viewed from a direction orthogonal to the slice plane and the horizontal position of the target plane orientation are the same, but the vertical positions differ. a vertical rotation angle calculation step of calculating a vertical rotation angle such that when the single crystal is rotated by the second rotation angle and then horizontally rotated by the second horizontal rotation angle, the plane orientation when viewed from a direction perpendicular to the slice plane coincides with the target plane orientation when the single crystal is rotated by the second rotation angle and then horizontally rotated by the second horizontal rotation angle, the plane orientation when viewed from a direction perpendicular to the slice plane coincides with the target plane orientation;a second mounting step of mounting the single crystal on the slicing device and then rotating it vertically by the vertical rotation angle based on the second rotation angle and the second horizontal rotation angle so that the horizontal positions of the plane orientation and the target plane orientation are the same when viewed from a direction perpendicular to the slicing plane, but different from each other, and the slicing step is performed.

7. A notch formation position determining device that determines notch formation positions in a single crystal used in the manufacture of multiple wafers having notches, comprising: a positional relationship acquiring unit that acquires the positional relationship between multiple notch formation candidate positions identified based on the crystal orientation of the single crystal and the plane orientation of the single crystal; a correction amount calculating unit that calculates a first rotation angle that, when the single crystal is rotated around the central axis of the single crystal from a state in which the notch formation candidate positions are located at the slice start position, makes the plane orientation and a target plane orientation coincide in vertical position when viewed from the central axis direction; and a notch formation position determining unit that determines, as the notch formation position, the notch formation candidate position such that the absolute value of the first rotation angle is equal to or greater than a specified angle.

8. A notch formation position determining device according to claim 7, wherein the specified angle is an acute angle, and the notch formation position determining unit determines the notch formation candidate position where the absolute value of the first rotation angle is 90° or less as the notch formation position.

9. A notch formation position determining device according to claim 7, wherein the correction amount calculation unit calculates a first horizontal rotation angle such that, when the single crystal is rotated by the first rotation angle and then rotated horizontally around a vertical axis, the plane orientation when viewed from a direction orthogonal to the slice plane that is orthogonal to the slice plane of the single crystal coincides with the target plane orientation, and when there are multiple notch formation candidate positions whose absolute value of the first rotation angle is equal to or greater than the specified angle, the notch formation position determining unit determines the notch formation candidate position with the smallest first horizontal rotation angle as the notch formation position.

10. A notch forming device comprising: a notch forming position determining device according to any one of claims 7 to 9; and a notch forming section that forms the notch at the notch forming position.

11. A wafer manufacturing system comprising: the notch forming device according to claim 10; a slicing device that produces the plurality of wafers by slicing the single crystal from the slicing start position; and a mounting device that mounts the single crystal on the slicing device so that the plane orientation when viewed from a direction perpendicular to the slicing plane that is perpendicular to the slicing plane of the single crystal coincides with the target plane orientation.

12. A notch formation position determining device according to claim 9, comprising: a notch forming unit that forms the notch at the notch formation position; a slicing device that produces the plurality of wafers by slicing the single crystal from the slicing start position; an attachment unit that attaches the single crystal to the slicing device; and a vertical rotation angle calculation unit, wherein when there is no candidate notch formation position where the absolute value of the first rotation angle is equal to or greater than the specified angle, the notch formation position determining unit determines, as the notch formation position, the candidate notch formation position where the absolute value of the first rotation angle is less than the specified angle; and when the candidate notch formation position where the absolute value of the first rotation angle is equal to or greater than the specified angle is determined as the notch formation position, the attachment unit attaches the single crystal to the slicing device based on the first rotation angle and the first horizontal rotation angle so that the plane orientation when viewed from a direction perpendicular to the slicing plane coincides with the target plane orientation; and the slicing device slices the single crystal attached by the attachment unit, when the notch formation candidate position, the absolute value of which is less than the specified angle, is determined as the notch formation position, the correction amount calculation unit calculates: a second rotation angle at which, when the single crystal with the notch formation position located at the slice start position is rotated about the central axis, the plane orientation when viewed from the central axis direction and the vertical position of the target plane orientation become different and are larger than the specified angle; and a second horizontal rotation angle at which, when the single crystal rotated by the second rotation angle is horizontally rotated about the vertical axis, the plane orientation when viewed from a direction orthogonal to the slice plane become the same as the horizontal position of the target plane orientation and the vertical positions become different; the vertical rotation angle calculation unit calculates a vertical rotation angle such that, when the single crystal is rotated by the second rotation angle and then horizontally rotated by the second horizontal rotation angle, the plane orientation when viewed from a direction orthogonal to the slice plane coincides with the target plane orientation when the single crystal is rotated vertically about a horizontal axis,the mounting device mounts the single crystal on the slicing device based on the second rotation angle and the second horizontal rotation angle so that the horizontal positions of the surface orientation and the target surface orientation when viewed from a direction perpendicular to the slicing surface are the same but different in the vertical direction, and the slicing device vertically rotates the single crystal mounted by the mounting device by the vertical rotation angle before slicing it.

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