Method for manufacturing gaas wafer

Abstract

The present application provides a method for manufacturing a GaAs wafer having excellent OF azimuthal stability even in a GaAs wafer having a deviation angle, and a GaAs wafer set. A method for manufacturing a GaAs wafer, wherein the method for manufacturing a GaAs wafer includes: a grinding step in which grinding including formation of a temporary positioning plane is performed on a peripheral surface of a GaAs crystal ingot; a slicing step in which a raw material wafer having a deviation angle is cut out by performing slicing processing on the GaAs crystal ingot after the grinding step; and a cleaving step in which, on the raw material wafer, scribe lines are formed in accordance with an orientation of a positioning plane determined with the temporary positioning plane as a reference, and cleaving is performed from the scribe lines to a peripheral surface of the raw material wafer to form a positioning plane, the cleaving step being a step in which cleaving is performed at a position where a length (interval A) of a line segment that is vertically extended from a midpoint of the cleaving to an outer side in a radial direction of the raw material wafer is 9 mm or more.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing GaAs wafers and GaAs wafer arrays obtained therefrom, and particularly to a method for manufacturing GaAs wafers in which positioning planes are formed in GaAs wafers having offset angles. Background Technology

[0002] Typically, a positioning plane (hereinafter also referred to as OF) indicating the crystal orientation or front and back surfaces of a semiconductor wafer is formed on its circumferential surface. During semiconductor device manufacturing, this positioning plane is used as a marker to detect the wafer's orientation and cutting direction. Typically, the positioning plane is formed as follows: after cylindrical grinding of a single-crystal ingot, the orientation is determined using an X-ray device, followed by planar grinding. Subsequently, the planar-ground single-crystal ingot is sliced ​​to obtain a semiconductor wafer with the positioning plane.

[0003] In the manufacture of semiconductor lasers that utilize the positioning plane as a resonant mirror, and in the chip processing of components fabricated at high density on semiconductor wafers, it is required to form an orientation plane as a reference with high precision according to the desired crystal orientation. As a method for forming the OF orientation with such high precision, Patent Document 1 discloses a method in which a scribe line is formed approximately parallel to a temporary positioning plane on one side of a semiconductor wafer on which a temporary positioning plane is formed; the portion of the semiconductor wafer located between the temporary positioning plane and the scribe line is inserted into a groove with an opening at the outer periphery of the end of a cleaving fixture; the cleaving fixture is rotated about an axis parallel to the temporary positioning plane, thereby cleaving the semiconductor wafer with the scribe line as the starting point to form the positioning plane.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2006-024839 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] Furthermore, since good crystallinity can be obtained when an epitaxial growth layer is formed on the wafer surface, wafers with an offset angle (off angle) are used. The offset angle represents the angle at which the crystal orientation of the wafer surface is tilted relative to the crystal orientation (e.g., the (100) plane, which is used as the epitaxial growth surface in the GaAs crystal structure (zinc sphalerite type structure). In wafers without an offset angle, the OF plane is perpendicular to the wafer surface, but in wafers with an offset angle, the OF plane is not perpendicular to the wafer surface (except in certain cases). Compared with wafers without an offset angle, wafers with this offset angle have problems in ensuring the orientation accuracy of the positioning plane. That is, in wafers with a certain offset angle, especially GaAs wafers, it is difficult to form the positioning plane with high accuracy and stability using conventional methods that include the technology described in Patent Document 1. In conventional methods, deviations in the orientation accuracy of the positioning planes between wafers present problems, such as the following: when multiple GaAs wafer sets are cut from the same GaAs ingot, it is inevitable that the GaAs wafer set will contain wafers with low orientation accuracy of the positioning planes, resulting in poor product yield for the GaAs wafer set. Furthermore, in recent years, the size of GaAs wafers used in the manufacture of LD (Laser Diode) devices has been increasing, and particularly when manufacturing such large-diameter wafers, the orientation accuracy of the positioning planes is poor when there is an offset angle.

[0009] Therefore, the object of the present invention is to provide a method for manufacturing GaAs wafers and a GaAs wafer assembly. According to the method for manufacturing GaAs wafers, even for GaAs wafers with an offset angle, the desired OF orientation will be accurately displayed and the deviation of OF orientation accuracy between wafers in the same GaAs ingot can be reduced, which helps to provide a GaAs wafer assembly with excellent OF orientation stability.

[0010] Solution for solving the problem

[0011] To address the aforementioned issues, the inventors conducted repeated and in-depth research, resulting in the completion of this invention. Specifically, the core structure of this invention is as follows.

[0012] The main structure of this invention is as follows.

[0013] (1) A method for manufacturing a GaAs wafer, wherein the method comprises: a grinding process in which grinding is performed on the peripheral surface of a GaAs ingot, including the formation of a temporary positioning plane; a slicing process in which the GaAs ingot after the grinding process is sliced ​​to cut a raw material wafer having an offset angle; and a cleaving process in which the raw material wafer is scribed according to the orientation of a positioning plane determined with reference to the temporary positioning plane, and cleaving is performed from the scribing line to the peripheral surface of the raw material wafer to form a positioning plane, wherein the cleaving process is a process in which the length (interval A) of a line segment extending perpendicularly from the midpoint of the cleaving towards the radial direction outside the raw material wafer to the peripheral surface of the raw material wafer is 9 mm or more.

[0014] (2) The method for manufacturing GaAs wafers according to (1), wherein the spacing A is 12 mm or more.

[0015] (3) The method for manufacturing GaAs wafers according to (1) or (2), wherein the deviation angle is 0.2° or more.

[0016] (4) The method for manufacturing a GaAs wafer according to any one of (1) to (3), wherein the angle between the main surface of the GaAs wafer and the surface forming the positioning plane is 89.8° or less or 90.2° or more.

[0017] (5) The method for manufacturing a GaAs wafer according to any one of (1) to (4), wherein the diameter of the GaAs wafer is 100 mm or more.

[0018] (6) The method for manufacturing a GaAs wafer according to any one of (1) to (4), wherein the diameter of the GaAs wafer is 150 mm or more.

[0019] (7) A method for manufacturing a GaAs wafer according to any one of (1) to (6), wherein the method for manufacturing a GaAs wafer further includes an edge grinding step after the cleaving step, wherein the peripheral surface of the GaAs wafer other than the positioning plane is ground in the edge grinding step.

[0020] (8) A GaAs wafer set, which is composed of multiple GaAs wafers with the same offset angle obtained from the same GaAs ingot, and is composed of all GaAs wafers with positioning planes after a cleaving process of positioning plane, wherein the average value of the positioning plane orientation accuracy of the GaAs wafer set is within ±0.010° ​​and the standard deviation of the positioning plane orientation accuracy of the GaAs wafer set is less than 0.009°.

[0021] (9) The GaAs wafer set according to (8), wherein the deviation angle of the GaAs wafer is 0.2° or more.

[0022] (10) The GaAs wafer assembly according to (8) or (9), wherein the angle between the main surface of the GaAs wafer and the surface forming the positioning plane is less than 89.8° or more than 90.2°.

[0023] (11) The GaAs wafer set according to any one of (8) to (10), wherein the average value of the positioning plane orientation accuracy of the GaAs wafer set is within ±0.010° ​​and the standard deviation of the positioning plane orientation accuracy of the GaAs wafer set is less than 0.005°.

[0024] (12) The GaAs wafer set according to any one of (8) to (11), wherein the orientation accuracy of the positioning plane of the GaAs wafer set is within ±0.020°.

[0025] (13) A GaAs wafer assembly with a positioning plane according to any one of (8) to (12), wherein the diameter of all the GaAs wafers is 100 mm or more.

[0026] (14) A GaAs wafer assembly with a positioning plane according to any one of (8) to (12), wherein the diameter of all the GaAs wafers is 150 mm or more.

[0027] The effects of the invention

[0028] According to the present invention, a method for manufacturing GaAs wafers can be provided, which, even for GaAs wafers with offset angles, will accurately exhibit the desired OF orientation and reduce the deviation in OF orientation accuracy between wafers within the same GaAs ingot, thus contributing to the provision of GaAs wafer sets with excellent OF orientation stability. Furthermore, according to the present invention, GaAs wafer sets with both a small average OF orientation accuracy and a small standard deviation of OF orientation accuracy can be provided. Attached Figure Description

[0029] Figure 1 It is a diagram illustrating the manufacturing process.

[0030] Figure 2A This diagram illustrates the angle between the main face of a GaAs wafer and the face that forms the positioning plane (OF plane).

[0031] Figure 2BThis diagram illustrates the angle between the main face of a GaAs wafer and the face that forms the positioning plane (OF plane).

[0032] Figure 3 This is a diagram illustrating the scribing and cleavage in this embodiment.

[0033] Figure 4A This diagram illustrates the distance (space A) between the circumferential surface of a GaAs wafer and the positioning plane.

[0034] Figure 4B This diagram illustrates the distance (space A) between the circumferential surface of a GaAs wafer and the positioning plane.

[0035] Figure 5 This is a schematic diagram illustrating the measurement of OF azimuth accuracy in this embodiment. Detailed Implementation

[0036] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, in Figures 2A to 5 In order to simplify the accompanying drawings, the size (length, thickness) of each structure is shown in proportion to its actual size, and there are also some exaggerated parts.

[0037] Reference Figure 1 The manufacturing process shown illustrates a method for manufacturing a GaAs wafer according to one embodiment of the present invention. This manufacturing method includes at least: a grinding process in which grinding, including the formation of a temporary positioning plane, is performed on the peripheral surface of a GaAs ingot; a slicing process in which slicing is applied to the GaAs ingot after the grinding process to cut a raw material wafer with an offset angle; and a cleaving process in which the raw material wafer is scribed according to the orientation of a positioning plane determined based on the temporary positioning plane, and cleaving is performed extending to the peripheral surface of the raw material wafer from this scribing line. A positioning plane is formed at a position where the length (interval A) of a line segment extending perpendicularly outward from the midpoint of the cleaving towards the radial direction of the raw material wafer to the peripheral surface of the raw material wafer is 9 mm or more. The details of each process will be described below. Furthermore, in... Figure 2A and Figure 2B The text describes the angle between the principal plane and the positioning plane of a GaAs wafer. Figure 3 The method for forming the actual positioning plane is explained in the text. Figure 4A and Figure 4B The text describes the distance (spacement A) from the midpoint of the cleavage to the circumferential surface of the wafer, as defined in this invention. Furthermore, in... Figure 5 The present invention illustrates a method for measuring OF orientation accuracy.

[0038] (Grinding process)

[0039] First, the peripheral surface of the GaAs ingot, fabricated by any method, is ground to smooth out any unevenness. Simultaneously, a temporary positioning plane, indicating the crystal orientation, is formed on the peripheral surface of the GaAs ingot. The grinding method is not particularly limited; the peripheral surface grinding can be performed using methods such as cylindrical grinding on a cylindrical grinding machine, and the temporary positioning plane can be formed using methods such as transverse grinding on a cylindrical grinding machine.

[0040] <GaAs crystal ingot>

[0041] As the GaAs ingot used to obtain GaAs wafers, single-crystal GaAs ingots obtained by any manufacturing method, such as the Czochralski (LEC) method, the Horizontal Bridgman (HB) method, the Vertical Temperature Gradient (VGF) method, and the Vertical Bridgman (VB) method, can be used. The diameter of the GaAs ingot is not limited. In this invention, since a positioning plane is formed at a certain interval from the circumferential surface of the raw material wafer, the diameter of the GaAs ingot is preferably at least 10 mm larger than the diameter of the desired GaAs wafer obtained in the end.

[0042] <Temporary positioning plane>

[0043] A temporary positioning plane only needs to be an indicator of its relative position to the set orientation of the positioning plane. Therefore, the orientation of the temporary positioning plane is not particularly limited, but it is preferable that the temporary positioning plane is formed in an orientation parallel or perpendicular to the set orientation of the positioning plane.

[0044] (Slicing process)

[0045] For GaAs ingots with temporary positioning planes formed through the aforementioned grinding process, multiple raw material wafers are cut using a slicing machine such as a wire saw. At this time, slicing is performed with a certain deviation angle relative to the growth direction of the single crystal, and with the same deviation angle between the cut wafers. Furthermore, the deviation angle can be arbitrarily set according to the intended use of the wafer in a semiconductor device, etc. Additionally, the term "same deviation angle" as used herein includes errors that are permissible within the scope of the effects of this invention, such as unavoidable errors in the manufacturing process.

[0046] <Aperture Angle>

[0047] As described above, the angle of the offset angle is not particularly limited. For example, when a GaAs wafer is used as the substrate of a multilayer substrate, in order to ensure good crystallinity of the layer grown on it, the offset angle is preferably 0.2° or more, more preferably 1° or more, and even more preferably 15° or less. Here, the orientation of the offset angle is not particularly limited as long as it is formed in an orientation other than horizontal with respect to the positioning plane (an orientation in which the angle between the main surface of the wafer and the OF surface is not 90°). For example, such as Figure 2A and Figure 2BAs shown, when the OF plane is the (0-1-1) plane, it can have a deviation angle that tilts the (100) plane toward (011) (i.e., tilts the perpendicular line <100> orthogonal to the (100) plane toward the <011> direction), and it can also have a deviation angle that tilts toward the (0-1-1) plane (i.e., tilts the perpendicular line <100> orthogonal to the (100) plane toward the <0-1-1> direction). Furthermore, in Figure 2A and Figure 2B In the case where the OF plane is the (0-1-1) plane, for example, when there is an offset angle that tilts the (100) plane towards (0-11) or (01-1), the angle between the main surface of the wafer and the OF plane is 90° regardless of the offset angle. Therefore, the orientation that makes the offset angle horizontal to the positioning plane is excluded. The same applies when the OF plane is not the (0-1-1) plane. Incidentally, the shape of the cross-section on the horizontal plane of the raw material wafer sliced ​​with a certain offset angle is different from that of the GaAs ingot before slicing, and strictly speaking, it becomes an elliptical shape. However, in the commonly used wafer size and offset angle, even compared with the raw material wafer sliced ​​without an offset angle, there is no dimensional difference that affects the specifications.

[0048] <Angle between the principal face of the GaAs wafer and the face forming the positioning plane>

[0049] like Figure 2A and Figure 2B As shown, when the principal face of the GaAs wafer is set as the xy plane and the vertical direction of the principal face is set as the z-axis, the angle between the principal face of the GaAs wafer and the plane forming the positioning plane (hereinafter also referred to as the OF plane) refers to the angle between the principal face of the GaAs wafer and the OF plane in the xz section when the OF plane is taken parallel to the y-axis. For example, when the OF plane is the (0-1-1) plane, the angle is 89.8° when the aforementioned deviation angle is 0.2° from the (100) plane toward the (011) plane, and the angle is 90.2° when the deviation angle is tilted toward the (0-1-1) plane. This angle is formed by the deviation angle and is an angle other than 90°, preferably 75.0° or more and 89.8° or less, and more preferably 90.2° or more and 105.0° or less. Furthermore, it is more preferably 75.0° or more and 89.0° or less or 91.0° or more and 105.0° or less. Figure 2A This illustrates the case where, without an offset angle (also referred to as just), the angle between the main face and the OF face of the wafer is 90°. Figure 2BThe diagram shows the case where the angle between the main face of the wafer and the OF face is 87° when there is a 3° deviation angle toward (011) (93° when the deviation angle is tilted toward the (0-1-1) face). Furthermore, it is common knowledge in the art that the further the angle between the main face of the wafer and the OF face is from 90°, the worse the orientation stability of the positioning plane becomes. However, by using the manufacturing method of the present invention, a positioning plane with excellent orientation stability can be formed. The same applies when the OF face is a face other than the (0-1-1) face.

[0050] (Cleavage process)

[0051] Next, a positioning plane is formed on the aforementioned raw material wafer. That is, as shown... Figure 3 As shown, for the raw material wafer 100, a guided cleaving line 150 is applied with a temporary positioning plane 110 as a reference. By cleaving the raw material wafer 100 with the cleaving line 150 as the starting point, a positioning plane 120 is formed. Here, the orientation of the cleaving line 150 can be determined based on its relative positional relationship with the temporary positioning plane 110, and can be any orientation such as (0-1-1), (0-11), (01-1), (011), etc., or other orientations. Specifically, after the cleaving line 150 is formed, a force is applied in the direction that extends the cleaving line 150, thereby causing the cleaving to propagate from the cleaving line 150 as the starting point to form a cleaving surface, thus forming the positioning plane 120. At this time, the cleaving line 150 is formed in such a way that the length of the line segment extending perpendicularly from the midpoint of the cleaving towards the outer radial direction of the raw material wafer 100 to the circumferential surface of the raw material wafer 100 is 9 mm or more. In the actual operation process, for the operator, Figure 4A The parallel arrangement of temporary positioning plane 110 and positioning plane 120, as shown, is easier to understand. On the other hand, in Figure 4B When the temporary positioning plane 110 and positioning plane 120 are in a 90° positional relationship, the area that is ground due to edge grinding can be reduced. Furthermore, the formation and cleaving of the scribing process in the cleaving step can be performed using any tool or manufacturing apparatus.

[0052] <Interval A>

[0053] For the interval A in this invention, an example is given. Figure 4A and Figure 4B Let me explain. First, as... Figure 4A Thus, when the positioning plane 120 is formed in an orientation parallel to the temporary positioning plane 110, the length of the line segment extending perpendicularly from the midpoint of the cleavage outward in the radial direction of the raw material wafer 100 to the circumferential surface of the raw material wafer 100 is the length of the perpendicular line drawn from the temporary positioning plane 110 to the positioning plane 120. Furthermore, in the case of... Figure 4BIn the case where the positioning plane 120 is formed in a position perpendicular to the temporary positioning plane 110, the sag with the cleavage as the chord becomes the length of a line segment that extends perpendicularly from the midpoint of the cleavage outward in the radial direction of the raw material wafer 100 to the periphery of the raw material wafer 100.

[0054] By making the interval A 9 mm or more, a more uniform strain is generated on the surface forming the positioning plane. Therefore, the fracture surface formed by cleavage propagating from the scribe line is formed along the crystal plane. The larger the interval A, the more stable the OF orientation accuracy. Therefore, the interval A is preferably 12 mm or more. In addition, from the viewpoint of effectively utilizing the wafer, the interval A is preferably 30 mm or less, and more preferably 25 mm or less. On the other hand, if the interval A is less than 9 mm, it is difficult to generate a more uniform strain on the surface forming the positioning plane in the cleavage predetermined plane. The propagation direction of cleavage is difficult to determine. Therefore, the formed fracture surface becomes a positioning plane with poor OF orientation accuracy.

[0055] (Edge grinding process)

[0056] Alternatively, the peripheral surface of the raw material wafer with the positioning plane formed can be ground using a rotating grinding wheel to shape the edge. This grinding process chamfers the peripheral surface of the wafer, preventing cracks in subsequent processes and allowing the wafer diameter to be shaped to a predetermined size. Furthermore, in this invention, the desired crystal plane precision is well exposed on the positioning plane formed through cleavage; therefore, grinding of this positioning plane should be avoided.

[0057] The applications of GaAs wafers produced through the above processes are not particularly limited, but their diameter is preferably 100 mm or more, and more preferably 150 mm or more, so that they can be used in the manufacture of various electronic devices, light-emitting elements, LD (LaserDiode) elements, etc. In particular, when the diameter is 150 mm or more, it is difficult to obtain excellent OF orientation accuracy for the positioning plane, but in this invention, high OF orientation accuracy can be obtained. Furthermore, since the positioning plane is accurately formed along the crystal plane during the cleaving process, the positioning plane has excellent OF orientation accuracy. Therefore, among all GaAs wafers produced from the same GaAs ingot and subjected to the cleaving process, obtained by processing all raw material wafers cut from the same GaAs ingot according to this manufacturing method, the average OF orientation accuracy is within ±0.010°, and the standard deviation of the OF orientation accuracy is 0.009° or less.

[0058] Next, we will describe the GaAs wafer array obtained using the above manufacturing method.

[0059] The GaAs wafer assembly based on the present invention is composed of GaAs wafers with the same offset angle obtained from the same GaAs ingot, and consists of all GaAs wafers with positioning planes after a cleaving process of the positioning plane. The average OF orientation accuracy of the GaAs wafer assembly is within ±0.010°, and the standard deviation of the OF orientation accuracy of the GaAs wafer assembly is 0.009° or less. Furthermore, the offset angle of the GaAs wafer is not particularly limited. For example, when the GaAs wafer is used as the substrate of a multilayer substrate, in order to ensure good crystallinity of the layer grown on it, the offset angle is preferably 0.2° or more, more preferably 1° or more, and even more preferably 15° or less. Furthermore, the angle between the main surface and the OF surface of the GaAs wafer is preferably 89.8° or less or 90.2° or more. The application of the GaAs wafer assembly based on the present invention is not particularly limited, but its diameter is preferably 100 mm or more, more preferably 150 mm or more, so that it can be used in the manufacture of various electronic devices, light-emitting elements, LD (Laser Diode) elements, etc.

[0060] <OF Azimuth Accuracy and its Standard Deviation>

[0061] In this specification, OF orientation accuracy refers to the deviation of a predetermined crystal plane from its self-forming positioning plane, expressed as an angle (°), using X-ray diffraction. In this case, within a single wafer, as described in the embodiments below... Figure 5 As shown, the OF orientation accuracy was measured at three predetermined locations on the positioning plane (the center of the positioning plane, and a location approximately 30% to 46% of the total OF length away from the center). Furthermore, the standard deviation of all measurements across multiple wafers was calculated. In the following embodiments, measurements were performed on multiple representative wafers extracted at equal intervals from the ingot; however, in measuring the OF orientation accuracy of a GaAs wafer group, it is preferable to measure all GaAs wafers that have undergone the cleaving process on the positioning plane within the same GaAs ingot. The measurement of OF orientation accuracy in a GaAs wafer group is preferably performed on 50 or more wafers. Regarding the OF orientation accuracy and its standard deviation, in a GaAs wafer group manufactured according to the manufacturing method of the present invention described above, the average value of the OF orientation accuracy (all measurements) is within ±0.010°, and the standard deviation of the OF orientation accuracy is 0.009° or less. More preferably, the standard deviation of the OF orientation accuracy is 0.005° or less. The smaller the standard deviation of OF orientation accuracy, the smaller the deviation of OF orientation accuracy between wafers within the ingot, and the lower the probability of measurement locations with OF orientation accuracy exceeding ±0.020°.

[0062] Here, even when OF orientation accuracy is poor, it is reflected in the manufacturing of semiconductor components by processing wafers. The SEMI specification, one of the standard specifications related to semiconductor devices, requires an overall OF orientation accuracy of ±0.5°. However, when a positioning plane is formed through cleaving, a more stringent reference value is required. In the inventor's view, a reference value within ±0.020° is necessary. Furthermore, among multiple wafers produced from the same GaAs ingot, many wafers with poor OF orientation accuracy will be produced; therefore, the product yield of wafers meeting the above reference value is also an important indicator. For the reasons described above, in the GaAs wafer group of the present invention, the average OF orientation accuracy is required to be within ±0.010° ​​and the standard deviation of the OF orientation accuracy is required to be 0.009° or less. Moreover, it is preferable that the range of twice the standard deviation (σ) of the average value of each measured value of OF orientation accuracy (average value - 2σ to average value + 2σ) is within ±0.020°. If twice the standard deviation relative to the average of the measurements is within ±0.020°, the deviation in OF orientation accuracy is smaller. Compared to a reference value of within ±0.020°, the yield is better, and the number of wafers that cannot be made into products can be reduced. Therefore, it is more preferable that the average OF orientation accuracy of the GaAs wafer group is within ±0.010° ​​and the standard deviation of OF orientation accuracy is less than 0.005°.

[0063] Example

[0064] The following examples illustrate in detail the method for manufacturing GaAs wafers based on the present invention.

[0065] (Example 1)

[0066] A single-crystal GaAs ingot with a diameter of 164.0 mm was prepared. The conical part and the tail were cut using an inner circumferential slicing machine. The ingot was then ground by cylindrical grinding to make the diameter of the GaAs ingot 161.5 mm.

[0067] Then, the orientation of the GaAs ingot after cylindrical grinding was determined using an X-ray device (GaAs-GOX (TSKK Ver.) of Rigaku Corporation, mounted on a cylindrical grinding machine: a CSN-7015 NC cylindrical grinding machine (NC3 axis) of Tokyo Seiki Works Co., Ltd.), and transverse grinding was performed, thereby forming a temporary positioning plane with a length of 15 mm.

[0068] Next, the GaAs ingot after the grinding process is sliced ​​using a wire saw so that the wafer cut from the GaAs ingot has a 3° offset angle from the (100) face toward the (011) direction, thereby cutting out a raw material wafer with a thickness of 785μm.

[0069] A cleaving line for guiding the positioning plane is scribed parallel to the temporary positioning plane. Cleaving is performed starting from this scribe line, and a positioning plane is formed at a position where the interval (interval A) between the positioning plane and the temporary positioning plane is 12 mm. The scribe line is formed using a scribe pen with a pointed tip, and the scribe area is on the circumferential surface of the wafer on one side of the pre-cleaving line. The scribe line is 4 mm long.

[0070] Then, holding the scribe line at the end of the wafer by hand, force is applied to expand the scribe line, thereby cleaving the wafer to form a positioning plane. Next, a grinding process is performed on the outer periphery of the wafer, excluding approximately 50 mm in width at the center of the cleaved positioning plane, to produce a 150 mm diameter wafer, thus obtaining the GaAs wafer assembly of Example 1. The scribe line is the area removed during the grinding process.

[0071] For each wafer in the obtained GaAs wafer group, X-ray diffraction measurements were used to determine... Figure 5 The OF orientation accuracy at each measurement position a to measurement position c is shown. In the above measurements, excluding several wafers extracted for inspection before the cleaving process, a total of 5 representative wafers were selected from the 102 wafers constituting the GaAs wafer group obtained after the cleaving process, with one wafer selected at equal intervals every 20 wafers. The measurement results are shown in Table 1. In the 5 wafers of Example 1, the OF orientation accuracy was all within ±0.020°, with an average value of 0.000° and a small standard deviation of 0.002°. Furthermore, the standard deviation relative to the average value was ±0.004°, indicating that the yield was also good across all the wafers constituting the GaAs wafer group. Then, the OF orientation accuracy was measured on all 102 GaAs wafers that constituted the cleavage wafer set. The results showed that the OF orientation accuracy was within ±0.020° at all measurement positions on all wafers, resulting in a 100% yield rate for the cleavage process with an orientation accuracy within this benchmark of ±0.020°. Furthermore, the average OF orientation accuracy was within ±0.010° ​​at all measurement positions on all wafers, and the standard deviation of the OF orientation accuracy was less than 0.005°.

[0072] <OF Azimuth Accuracy Measurement Method>

[0073] The OF orientation accuracy in Example 1 was evaluated as follows. For the obtained GaAs wafer, the OF orientation accuracy (°) relative to the predetermined OF crystal plane (0-1-1) was determined by X-ray diffraction measurement (Rigaku Corporation 2991F2). Specifically, as follows... Figure 5 As shown, while irradiating the OF surface with X-rays, the wafer is arbitrarily rotated in the direction of the black arrow with the OF surface as the reference. Then, by comparing the rotation angle of the crystal plane relative to the predetermined OF surface to produce Bragg diffraction, the offset of the crystal plane relative to the physical plane is calculated and used as the OF orientation accuracy. For example, when the OF surface orientation is (0-1-1), θ = 22.5° and 2θ = 45°, therefore, the offset relative to this angle is called the OF orientation accuracy. In Example 1, the total length of the OF is approximately 50 mm, and the central part of the OF ( Figure 5 (b) and points 20mm away from the center of OF respectively ( Figure 5 These three locations (a, c) are set as the measurement positions for OF azimuth accuracy.

[0074] (Example 2)

[0075] The scribing was formed with a spacing of 10 mm. Otherwise, GaAs wafers were fabricated in the same manner as in Example 1, and the OF orientation accuracy of the obtained positioning plane was measured on 5 wafers.

[0076] (Example 3)

[0077] The scribing was formed so that the spacing A was 9 mm. Otherwise, GaAs wafers were fabricated in the same manner as in Example 1, and five wafers representing the OF orientation accuracy of the obtained positioning plane were measured.

[0078] (Comparative Example 1)

[0079] From the 102 GaAs wafers obtained, one wafer was selected at equal intervals of every 50 wafers, for a total of 3 wafers, as representatives for measurement. A scribing was formed with an interval A of 8 mm. Otherwise, GaAs wafers were fabricated in the same manner as in Example 1, and the OF orientation accuracy of the resulting positioning plane was measured.

[0080] (Comparative Example 2)

[0081] From the obtained GaAs wafer set of 102 wafers, one wafer was selected at equal intervals of every 50 wafers, for a total of 3 wafers, as representatives for measurement. A scribing was formed with a spacing A of 6 mm. Otherwise, GaAs wafers were fabricated in the same manner as in Example 1, and the OF orientation accuracy of the resulting positioning plane was measured.

[0082] [Table 1]

[0083]

[0084] As shown in Table 1, in Comparative Examples 1 and 2, there were measurements with OF azimuth accuracy exceeding ±0.020°, indicating a large deviation and a large standard deviation. In Examples 1 to 3, there were no measurements with OF azimuth accuracy exceeding ±0.020°, the average value was within ±0.010°, and the standard deviation was below 0.005°, indicating a small deviation.

[0085] Explanation of reference numerals in the attached figures

[0086] 100. Raw material wafer; 110. Temporary positioning plane; 120. Positioning plane; 150. Scribing line.

Claims

1. A method for manufacturing a GaAs wafer, wherein, The method for manufacturing this GaAs wafer includes: The grinding process involves grinding the circumferential surface of a GaAs ingot, including the formation of temporary positioning planes. The slicing process involves slicing the GaAs ingot after the grinding process to cut raw material wafers with an offset angle. as well as In the cleaving process, the raw material wafer is scribed with lines aligned with the orientation of a positioning plane determined based on the temporary positioning plane. Cleaving then extends from these scribed lines to the circumferential surface of the raw material wafer to form the positioning plane. The cleaving process is a process in which the cleaving is performed at a position where the length (interval A) of a line segment extending perpendicularly from the midpoint of the cleaving towards the outer side of the radius of the raw material wafer to the circumference of the raw material wafer is 9 mm or more.

2. The method for manufacturing a GaAs wafer according to claim 1, wherein, The interval A is 12mm or more.

3. The method for manufacturing a GaAs wafer according to claim 1 or 2, wherein, The deviation angle is greater than 0.2°.

4. The method for manufacturing a GaAs wafer according to claim 1 or 2, wherein, The angle between the main surface of the GaAs wafer and the surface forming the positioning plane is less than 89.8° or greater than 90.2°.

5. The method for manufacturing a GaAs wafer according to claim 1 or 2, wherein, The GaAs wafer has a diameter of 100 mm or more.

6. The method for manufacturing a GaAs wafer according to claim 1 or 2, wherein, The diameter of the GaAs wafer is 150 mm or more.

7. The method for manufacturing a GaAs wafer according to claim 1 or 2, wherein, The method for manufacturing the GaAs wafer further includes a grinding step after the cleaving step, in which the peripheral surface of the GaAs wafer outside the positioning plane is ground.

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