Semiconductor crystal wafer manufacturing device and manufacturing method

Abstract

The purpose of the present invention is to provide a device and a method for manufacturing semiconductor crystal wafer, the device and the method being capable of easily and reliably manufacture semiconductor crystal wafers of high-quality. This manufacturing method for a SiC wafer which is a semiconductor crystal wafer, includes: a groove machining step (STEP 100 / FIG. 1), a polishing step (STEP 110 / FIG. 1), a cutting step (STEP 120 / FIG. 1), a first surface machining step (STEP 130 / FIG. 1), and a second surface machining step (STEP 140 / FIG. 1), wherein in the cutting step, before a SiC ingot 10 is cut into slices by advancing a plurality of wires 42 arranged in a plurality of concave grooves 11 while making them revolving, a deviation angle of the plurality of wires 42 with respect to the plurality of concave grooves 11 is detected from an image captured by an imaging means 44 that is provided at a position facing an ingot supporting unit 43 that supports the SiC ingot 10 across the plurality of wires 42 and captures an image of the plurality of wires 42 disposed in the plurality of concave grooves 11, and the deviation angle is adjusted to zero.

Description

TECHNICAL FIELD

[0001] The present invention relates to a device and a method for manufacturing semiconductor crystal wafer, which cuts a semiconductor crystal ingot, that has been ground into a cylindrical shape, into slices as wafers.BACKGROUND ART

[0002] Conventionally, as for the manufacturing method of SiC wafer of such semiconductor crystal wafer, as shown in the following Patent Literature 1, it is known to include a wafer shape forming step, followed by a process-affected layer removal step, and finally a mirror polishing step. The wafer shape forming step includes: an ingot forming step, in which a single crystal SiC block grown by crystallization is processed into a cylindrical ingot; a crystal orientation forming step, in which a notch is formed on a part of the outer periphery of the ingot to become a mark showing a crystal orientation of the ingot; a slicing step, in which the single crystal SiC ingot is sliced into thin disc-shaped SiC wafers; a planarization step, in which the SiC wafers are planarized by using abrasive grains that do not reach the modified Mohs hardness; a mark forming step of forming a mark; and a chamfering step of chamfering the outer peripheral portion. In the process-affected layer removal step, the process-affected layer introduced into the SiC wafer in the previous steps is removed. The mirror polishing step is a chemical mechanical polishing (CMP) step uses both the mechanical action of a polishing pad and the chemical action of slurry to perform polishing.[Citation List][Patent Literature]

[0003] Patent Literature 1: Japanese Patent Laid-Open No. 2020-15646SUMMARY OF INVENTION[Technical Problem]

[0004] However, the above-mentioned conventional method for manufacturing a SiC wafer has the problems of multiple and complex manufacturing processes, complex device structure, and high manufacturing cost.

[0005] On the other hand, if the process is simplified, it is difficult to stably obtain the required quality for SiC wafers.

[0006] In view of this, an object of the present disclosure is to provide a device and a method for manufacturing a semiconductor crystal wafer that can easily and reliably manufacture high-quality semiconductor crystal wafers.[Solution to Problem]

[0007] A semiconductor crystal wafer manufacturing device of the first invention is a device for manufacturing semiconductor crystal wafer, which cuts a semiconductor crystal ingot, that has been ground into a cylindrical shape, into slices as wafers, the device comprising: a groove machining drum grindstone configured for forming a plurality of concave grooves surrounding an entire side surface of the semiconductor crystal ingot, wherein a plurality of convex portions corresponding to the plurality of concave grooves are formed on a side surface of the groove machining drum grindstone; and a wire saw device configured for cutting the semiconductor crystal ingot into slices by advancing a plurality of wires disposed in the plurality of concave grooves while making the plurality of wires revolve; an imaging means, which is provided in the wire saw device at a position facing an ingot supporting means that supports the semiconductor crystal ingot across the plurality of wires, so as to image the plurality of wires disposed in the plurality of concave grooves; and a slider provided with the imaging means on a front end side thereof and capable of advancing the imaging means from a frame of the wire saw device to the position where imaging is performed and retracting the imaging means after imaging; wherein a deviation angle of the plurality of wires with respect to the plurality of concave grooves is detected from an image captured by the imaging means.

[0008] A semiconductor crystal wafer manufacturing device of the second invention is a device for manufacturing semiconductor crystal wafer, which cuts a semiconductor crystal ingot, that has been ground into a cylindrical shape, into slices as wafers, the device comprising: a groove machining drum grindstone configured for forming a plurality of concave grooves surrounding an entire side surface of the semiconductor crystal ingot, wherein a plurality of convex portions corresponding to the plurality of concave grooves are formed on a side surface of the groove machining drum grindstone; and a wire saw device configured for cutting the semiconductor crystal ingot into slices by advancing a plurality of wires disposed in the plurality of concave grooves while making the plurality of wires revolve; an imaging means provided in the wire saw device at a position facing an ingot supporting means that supports the semiconductor crystal ingot across the plurality of wires, so as to image the plurality of wires disposed in the plurality of concave grooves; a slider provided with the imaging means on a front end side thereof and capable of advancing the imaging means to the position where imaging is performed; and an attaching / detaching means configured for detachably attaching the slider to the wire saw device; wherein a deviation angle of the plurality of wires with respect to the plurality of concave grooves is detected from an image captured by the imaging means.

[0009] According to the semiconductor crystal wafer manufacturing device of the first or second invention, a groove machining drum grindstone, which forms a plurality of concave grooves surrounding the entire side surface of a semiconductor crystal ingot and in which a plurality of convex portions corresponding to the plurality of concave grooves are formed on a side surface thereof, and an additional member corresponding to the groove machining drum grindstone are provided.

[0010] The first additional member is a wire saw device that makes a plurality of wires disposed in a plurality of concave grooves formed in the entire side surface of the semiconductor crystal ingot revolve.

[0011] The second additional member is an imaging means. The imaging means is provided in the wire saw device at a position facing an ingot supporting means that supports the semiconductor crystal ingot across the plurality of wires, so as to image a plurality of wires disposed in the plurality of concave grooves. The imaging means includes a slider that moves the imaging means to a position where imaging is performed. Further, the second invention includes an attaching / detaching means capable of detachably attaching the slider to the wire saw device.

[0012] In the above configuration, for the plurality of concave grooves formed in the entire side surface of the semiconductor crystal ingot by the groove machining drum grindstone, by accurately arranging the plurality of wires in the plurality of concave grooves, the semiconductor crystal ingot can be cut into slices with high accuracy by the plurality of wires.

[0013] Here, in order to accurately dispose the plurality of wires in the plurality of concave grooves, the deviation angle of the traveling direction of the plurality of wires with respect to the traveling direction (longitudinal direction) of the plurality of concave grooves is detected from the image captured by the imaging means.

[0014] Therefore, the deviation angle can be accurately grasped, and for example, adjustment of the supporting means of the semiconductor crystal ingot, adjustment of the wire saw bobbin, and the like can be performed, so as to cancel the deviation angle. After the adjustment, in the first invention, the imaging means can be retracted by the slider, and in the second invention, the slider itself with the imaging means provided at the front end can be removed, and the imaging means and the slider do not become an obstacle in a subsequent step (for example, a cutting step) or the like.

[0015] As described above, according to the semiconductor crystal wafer manufacturing device of the first invention or the second invention, the semiconductor crystal ingot can be cut into slices with high accuracy, and a high-quality semiconductor crystal wafer can be easily and reliably manufactured.

[0016] A semiconductor crystal wafer manufacturing device of the third invention is the semiconductor crystal wafer manufacturing device according to the first or second invention. The slider makes the imaging means slide at the position, and the imaging means continuously images the plurality of wires arranged in the plurality of concave grooves.

[0017] According to the semiconductor crystal wafer manufacturing device of the third invention, even in the case where a plurality of wires corresponding to a plurality of concave grooves do not enter the captured image at one time, by sliding the imaging means via the slider, it is possible to detect and adjust the deviation angle with respect to the entire plurality of wires corresponding to the plurality of concave grooves by performing scanning and continuous imaging.

[0018] As described above, according to the semiconductor crystal wafer manufacturing device of the third invention, the semiconductor crystal ingot can be cut into slices with higher accuracy, and a high-quality semiconductor crystal wafer can be easily and reliably manufactured.

[0019] A semiconductor crystal wafer manufacturing device of the fourth invention is the semiconductor crystal wafer manufacturing device according to the first or second invention. The ingot supporting means may include a deviation angle adjusting means. The deviation angle adjusting means is configured to rotate and fix the semiconductor crystal ingot so that the deviation angle detected from the image captured by the imaging means becomes zero.

[0020] According to the semiconductor crystal wafer manufacturing device of the fourth invention, the semiconductor crystal ingot can be fixed at the fitted position by rotating the deviation angle adjusting means so as to cancel the deviation angle to become zero by the deviation angle adjusting means which is configured in the ingot supporting means and rotates about the rotation shaft extending perpendicularly to the cut surface by the plurality of wires to fix the semiconductor crystal ingot at the position where the deviation angle becomes zero.

[0021] Accordingly, the deviation angle of the traveling direction of the plurality of wires with respect to the traveling direction (longitudinal direction) of the plurality of concave grooves becomes zero, and the plurality of wires can be accurately arranged in the plurality of concave grooves.

[0022] As described above, according to the semiconductor crystal wafer manufacturing device of the fourth invention, the semiconductor crystal ingot can be cut into slices with high accuracy with a simple configuration, and a high-quality semiconductor crystal wafer can be easily and reliably manufactured

[0023] A semiconductor crystal wafer manufacturing method of the fifth invention is a method for manufacturing semiconductor crystal wafer, which cuts a semiconductor crystal ingot, that has been ground into a cylindrical shape, into slices as wafers, the method comprising: a groove machining step for forming a plurality of concave grooves surrounding an entire side surface of the semiconductor crystal ingot; and a cutting step performed by a wire saw device which cuts the semiconductor crystal ingot into slices by advancing a plurality of wires disposed in a plurality of concave grooves formed in the groove machining step while making the plurality of wires revolve; wherein, in the groove machining step, a groove machining drum grindstone in which a plurality of convex portions corresponding to the plurality of concave grooves are formed on a side surface thereof is pressed against the semiconductor crystal ingot while the groove machining drum grindstone and the semiconductor crystal ingot are rotated respectively on rotation shafts parallel to each other to form the concave grooves; and wherein, in the cutting step, before the semiconductor crystal ingot is cut into slices by advancing the plurality of wires disposed in the plurality of concave grooves while making the plurality of wires revolve, a slider provided with an imaging means on a front side thereof is advanced from a frame of the wire saw device, and wherein, at a position facing an ingot supporting means that supports the semiconductor crystal ingot across the plurality of wires, the plurality of wires disposed in the plurality of concave grooves are imaged by the imaging means, and a deviation angle of the plurality of wires with respect to the plurality of concave grooves is detected from a captured image, wherein the deviation angle is adjusted to zero, and the slider is retracted after the deviation angle is adjusted.

[0024] A semiconductor crystal wafer manufacturing method of the sixth invention is a method for manufacturing semiconductor crystal wafer, which cuts a semiconductor crystal ingot, that has been ground into a cylindrical shape, into slices as wafers, the method comprising: a groove machining step for forming a plurality of concave grooves surrounding an entire side surface of the semiconductor crystal ingot; and a cutting step performed by a wire saw device which cuts the semiconductor crystal ingot into slices by advancing a plurality of wires disposed in the plurality of concave grooves formed in the groove machining step while making the plurality of wires revolve; wherein, in the groove machining step, a groove machining drum grindstone in which a plurality of convex portions corresponding to the plurality of concave grooves are formed on a side surface thereof is pressed against the semiconductor crystal ingot while the groove machining drum grindstone and the semiconductor crystal ingot are rotated respectively on rotation shafts parallel to each other to form the concave grooves; and wherein, in the cutting step, before the semiconductor crystal ingot is cut into slices by advancing the plurality of wires disposed in the plurality of concave grooves while making the plurality of wires revolve, a slider provided with an imaging means on a front side thereof is advanced, and wherein, at a position facing an ingot supporting means that supports the semiconductor crystal ingot across the plurality of wires, the plurality of wires disposed in the plurality of concave grooves are imaged by the imaging means, and a deviation angle of the plurality of wires with respect to the plurality of concave grooves is detected from a captured image, wherein the deviation angle is adjusted to zero, and the slider is removed after the deviation angle is adjusted.

[0025] According to the semiconductor crystal wafer manufacturing method of the fifth or sixth invention, a groove machining step for forming a plurality of concave grooves corresponding to a plurality of convex portions of a groove machining drum on the entire side surface of a semiconductor crystal ingot, and a cutting step for cutting the semiconductor crystal ingot into slices by advancing a plurality of wires disposed in the plurality of concave grooves formed in the groove machining step while making the plurality of wires revolve are performed.

[0026] Here, for the plurality of concave grooves formed in the entire side surface of the semiconductor crystal ingot by the groove machining drum grindstone, by accurately arranging the plurality of wires in the plurality of concave grooves, the semiconductor crystal ingot can be cut into slices with high accuracy by the plurality of wires.

[0027] In order to accurately dispose the plurality of wires in the plurality of concave grooves, in the wire saw device, the deviation angle of the traveling direction of the plurality of wires with respect to the traveling direction (longitudinal direction) of the plurality of concave grooves is detected from an image captured by an imaging means that is provided at a position facing the ingot supporting means that supports the semiconductor crystal ingot across the plurality of wires and captures an image of the plurality of wires disposed in the plurality of concave grooves.

[0028] Therefore, the deviation angle can be accurately grasped, and for example, adjustment of the supporting means of the semiconductor crystal ingot, adjustment of the wire saw bobbin, and the like can be performed so as to cancel the deviation angle. After the adjustment, in the fifth invention, the imaging means can be retracted by the slider, and in the sixth invention, the slider itself provided with the imaging means at the front end can be removed, and the imaging means and the slider do not become an obstacle in a subsequent step (for example, a cutting step) or the like

[0029] As described above, according to the semiconductor crystal wafer manufacturing method of the fifth invention or the sixth invention, the semiconductor crystal ingot can be cut into slices with high accuracy, and a high-quality semiconductor crystal wafer can be easily and reliably manufactured.

[0030] A semiconductor crystal wafer manufacturing method of the seventh invention is the semiconductor crystal wafer manufacturing method according to the fifth or sixth invention. In the cutting step, prior to the cutting, the ingot supporting means performs a deviation angle adjustment step to rotate and fix the semiconductor crystal ingot so that the deviation angle detected from the image captured by the imaging means becomes zero.

[0031] According to the semiconductor crystal wafer manufacturing method of the seventh invention, prior to the cutting, rotation is performed and the semiconductor crystal ingot is fixed at a matching position such that the deviation angle is canceled to become zero, by a deviation angle adjustment step in which rotation around a rotation shaft extending perpendicularly to the cut surface formed by the plurality of wires is performed in the ingot supporting means, and the semiconductor crystal ingot is fixed at a position where the deviation angle becomes zero.

[0032] Accordingly, the deviation angle of the traveling direction of the plurality of wires with respect to the traveling direction (longitudinal direction) of the plurality of concave grooves becomes zero, and the plurality of wires can be accurately arranged in the plurality of concave grooves.

[0033] As described above, according to the semiconductor crystal wafer manufacturing method of the seventh invention, a semiconductor crystal ingot can be cut into slices with high accuracy with a simple configuration, and a high-quality semiconductor crystal wafer can be easily and reliably manufactured.BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a flowchart showing an entire process of a method of manufacturing a SiC wafer (semiconductor crystal wafer) of the present embodiment. FIG. 2 is an explanatory view showing a manufacturing device of the SiC wafer, which is composed of a groove machining step and a pad groove forming step in the manufacturing method of the SiC wafer of FIG. 1, according to the present embodiment. FIG. 3 is an explanatory view showing the contents of a groove machining step and a polishing step in the method of manufacturing the SiC wafer of FIG. 1. FIG. 4 is an explanatory view showing the content of a cutting step in the method of manufacturing the SiC wafer of FIG. 1. FIG. 5 is an explanatory view showing a deviation angle adjustment in a cutting step in the method of manufacturing the SiC wafer of FIG. 1. FIG. 6 is an explanatory view showing the contents of a first surface machining step and a second surface machining step in the method of manufacturing the SiC wafer of FIG. 1 DESCRIPTION OF EMBODIMENTS

[0035] As shown in FIG. 1, in the present embodiment, a method for manufacturing a SiC wafer which is a semiconductor crystal wafer is a method of obtaining a SiC wafer cut into a slice shape from a SiC ingot having been ground into a cylindrical shape, and includes: a groove machining step (STEP 100 / FIG. 1), a polishing step (STEP 110 / FIG. 1), a cutting step (STEP 120 / FIG. 1), a first surface machining step (STEP 130 / FIG. 1), and a second surface machining step (STEP 140 / FIG. 1).

[0036] With reference to FIG. 2 to FIG. 6, details of each step and a device for manufacturing a SiC wafer according to the present embodiment will be described.

[0037] A groove machining drum grindstone 20 used in the groove forming step (STEP 100 / FIG. 1) shown in FIG. 2 is used in common to perform pad groove forming machining in advance.

[0038] The groove machining drum grindstone 20 is a drum grindstone used to form a plurality of concave grooves 11 surrounding the entire side surface of a SiC ingot 10, and a plurality of convex portions 21 corresponding to the plurality of concave grooves 11 are formed on a side surface of the groove machining drum grindstone 20.

[0039] First, in the pad groove forming machining, a cylindrical polishing pad 30 for grounding a plurality of concave grooves 11 is machined, wherein the groove machining drum grindstone 20 is pressed against the polishing pad 30 while the polishing pad 30 and the groove machining drum grindstone 20 are respectively rotated on rotation shafts parallel to each other, thereby a plurality of pad grooves 31 corresponding to the plurality of convex portions 21 being formed on the entire side surface of the polishing pad 30

[0040] At this time, the pad grooves 31 are formed in a state in which the polishing pad 30 (impregnated with an appropriate amount of moisture as necessary) is solidified by being frozen. Then, the polishing pad 30 in which the pad grooves 31 are formed is used in the following steps after thawing (and drying if necessary) treatment.

[0041] Next, in the groove machining step (STEP 100 / FIG. 1), a plurality of concave grooves 11 surrounding the entire side surface of the SiC ingot 10 are formed by using the common groove machining drum grindstone 20.

[0042] Specifically, in the groove machining step (STEP 100 / FIG. 1), while the groove machining drum grindstone 20, which has a plurality of convex portions 21 corresponding to a plurality of concave grooves 11 formed on the entire side surface, and the SiC ingot 10 are respectively rotated on rotation shafts parallel to each other, the groove machining drum grindstone 20 is pressed against the SiC ingot 10 to thereby form the concave grooves 11.

[0043] At this time, the SiC ingot 10 is such supported to rotate freely while both end surfaces of the SiC ingot 10 are protected by a pair of protective plates 15, 15

[0044] The protective plate 15 is, for example, made of synthetic resin such as polyvinyl chloride, and is bonded to the SiC ingot 10 via an adhesive as necessary.

[0045] The pair of protective plates 15 and 15 can protect both ends of the SiC ingot 10 and prevent chipping and cracking of both ends. Therefore, a plurality of concave grooves 11 can be formed close to end edges of both end surfaces, so that a larger amount of cutting can be performed to obtain a larger amount of SiC wafers 100 described below.

[0046] In addition, when the SiC ingot 10 is clamped and fixed onto the rotation shaft, the protective plates 15 and 15 can be processed (for example, drilled) as needed to fix them. In addition, even in this case, the SiC ingot 10 will not be damaged because the SiC ingot 10 itself is not processed.

[0047] The plurality of concave grooves 11 of the SiC ingot 10 and the plurality of pad grooves 31 of the polishing pad 30 formed by the above-described processing steps have the same shape (the same pitch) corresponding to the plurality of convex portions 21 of the groove machining drum grindstone 20.

[0048] Therefore, as shown in FIG. 3, at approximately the same time as forming a plurality of concave grooves 11 in the SiC ingot 10 in the groove machining step (STEP 100 / FIG. 1), in the polishing step (STEP 110 / FIG. 1), polishing along the concave grooves 11 can be performed by a plurality of pad convex portions 32 (the convex portions between two adjacent pad grooves 31, 31) of the polishing pad 30 having the same pitch as the concave grooves 11.

[0049] Here, in the polishing step (STEP 110 / FIG. 1), polishing may be performed by CMP slurry (chemical mechanical liquid abrasive). However, powder abrasive (buffing abrasive) may be added intermittently or continuously to the surface of the polishing pad 30.

[0050] Further, as shown in FIG. 4A, in the cutting step (STEP 120 / FIG. 1), a plurality of wires 42 stretched between the bobbins 41 and 41 of a wire saw device 4, which is a cutting device, are disposed in the plurality of concave grooves 11 formed in the groove machining step (STEP 100 / FIG. 1), and the SiC ingot 10 is cut into slices by advancing while rotating the wires 42.

[0051] At this time, by accurately arranging the plurality of wires 42 in the plurality of concave grooves 11, the SiC ingot 10 can be cut into slices at one time with high accuracy.

[0052] Therefore, in the present embodiment, the wire saw device 4 includes an imaging means 44 that is provided at a position facing an ingot supporting means 43 that supports the SiC ingot 10 across the plurality of wires 42 and images the plurality of wires 42 disposed in the plurality of concave grooves 11.

[0053] The ingot supporting means 43 supports the SiC ingot 10, and the base portion thereof is constituted by, for example, a rotary table, and has a function as a deviation angle adjusting means which rotates in the direction of an arrow around a rotation shaft Z (vertical direction in the drawing) extending perpendicularly to a cut surface caused by the plurality of wires 42 and is fixed at an arbitrary position.

[0054] The imaging means 44 is constituted by, for example, a CCD camera or the like, and as shown in FIG. 4B, is connected to a frame 45 of the wire saw device 4 via a connection plate 46 of a hollow frame type, and is disposed on a front end side of a slider 47 configured to be capable of advancing and retreating in the hollow frame of the connection plate 46 (more precisely, the connection plate 46 and an auxiliary connection plate 46' integrally formed with the connection plate 46) so as to image a plurality of wires 42 overlapping with the plurality of concave grooves 11.

[0055] Here, the slider 47 may be an electric slider or a manual slider that is manually slid, and is detachably attached to the frame 45 of the wire saw device 4 via a connection plate 46 (corresponding to attaching and detaching means of the present invention). In the present embodiment, the connection plate 46 is detachably fixed to the frame 45 by screwing, but the detachable fixing means is not limited thereto.

[0056] In the present embodiment, an electric table (a vertical movement table) for focus / zoom adjustment is provided between the imaging means 44 and the slider 47, but the electric table may be omitted.

[0057] In the cutting step (STEP 120 / FIG. 1) by the wire saw device 4 configured as described above, first, a deviation angle adjustment step is performed prior to the cutting.

[0058] In the deviation angle adjustment step, first, the front end side of the slider 47 is advanced, and the imaging direction of the imaging means 44 is disposed at an imaging position where the plurality of concave grooves 11 and the plurality of wires 42 overlap (so as to capture an image from directly below to directly above the SiC ingot 10 in the drawing).

[0059] In this state, an image captured by the imaging means 44 is acquired, and a deviation angle 42 of the plurality of wires with respect to the plurality of concave grooves 11 are detected from the captured image.

[0060] At this time, even when the plurality of wires 42 with respect to the plurality of concave grooves 11 cannot be captured in the captured image at one time, by sliding the imaging means 44 via the slider 47 and continuously capturing images, it is possible to detect the deviation angle of the entire plurality of wires 42 with respect to the plurality of concave grooves 11 by continuously capturing images by scanning.

[0061] Specifically, as shown in an actual captured image in FIG. 5, it is possible to detect a deviation angle (not parallel) between the traveling direction of the concave grooves 11 (the left-right direction in the drawing) and the traveling direction of the wires 42 (the left-right direction in the drawing).

[0062] Although the deviation angle may be detected visually, for example, by performing edge detection processing or the like after binarizing the captured image, the traveling direction of the width position (vertical position) of the concave grooves 11 and the traveling direction of the width position (vertical position) of the wires 42 may be detected as straight lines, and the deviation angle may be detected from the inclination of these straight lines by image processing.

[0063] Next, the supporting means 43 is rotated around the rotation shaft Z so as to cancel the detected deviation angle and set the deviation angle to zero. After confirming that the deviation angle is zero in the captured image, the SiC ingot 10 is fixed at that position.

[0064] Here, in the case that the angle adjusting means is constituted by an electric turntable and the deviation angle adjustment means is configured to be automatically adjustable from the captured image, feedback control may be performed to output a deviation corresponding to the inclination between the straight lines as the number of output steps to the stepping motor of the turntable.

[0065] When the adjustment of the deviation angle is completed in this manner, the front end side of the slider 47 is retracted. Then, the slider 47 itself is detached from the frame 45 of the wire saw device 4 via the connection plate 46, and the slider 47 and the connecting means 44 are not disturbed or damaged in the subsequent cutting step or the like.

[0066] As described above, by accurately arranging the plurality of wires 42 in the plurality of concave grooves 11, the SiC ingot 10 can be cut into slices at one time with high accuracy.

[0067] In addition, as shown in FIG. 5, since the SiC wafer 100 obtained by cutting into slices is uniformly chamfered at its corners by the polishing pad 30 whose peripheral edges are accurately aligned in pitch, it is not necessary to perform chamfering or the like again after cutting.

[0068] Here, regarding the structure of the semiconductor crystal wafer (SiC wafer) manufacturing device (cutting device) of this embodiment, it is constituted by the groove machining drum grindstone 20, the polishing pad 30 and the wire saw device 40.

[0069] Next, as shown in FIG. 6, in the first surface machining step (STEP 130 / FIG. 1), one surface 110 of the cut surface is used as a support surface, and the other surface 120 is subjected to mechanical polishing (high-precision grinding).

[0070] Specifically, in the first surface machining step (STEP 130 / FIG. 1), grinding process is performed by a mechanical polishing device 50 (ultra-high synthetic high-precision grinding device) that performs mechanical polishing.

[0071] The mechanical polishing device 50 includes a spindle 51 and a diamond grindstone 53 located on a platen 52 serving as a platen.

[0072] First, one surface 110 of the SiC wafer 100 faces upward and is sucked to and supported by a porous vacuum chuck 54 which is a suction plate of the spindle 51, and the other surface 120 faces downward and is ground with the diamond grindstone 53.

[0073] At this time, the spindle 51 and the diamond grindstone 53 are rotationally driven by a driving device (not shown), and the other surface 120 is ground by pressing the spindle 51 against the diamond grindstone 53 using a compressor or the like (not shown).

[0074] Incidentally, after the grinding process, the diamond grindstone 53 may be dressed by a dresser or the like.

[0075] Furthermore, the mechanical polishing device 50 may have functional water supply piping as necessary, so that multiple types of functional water can be used during the process.

[0076] Next, in the second surface machining step (STEP140 / FIG. 1), the other surface 120 which has been subjected to the high-precision grinding process in the first surface machining step is directed upward, and the same high-precision grinding process as in the first surface machining step is performed on the one surface 110.

[0077] That is, the other side 120 is facing upward and is sucked to and supported by the porous vacuum chuck 54 which is the suction plate of the spindle 51, and the one side 110 is facing downward and is ground with the diamond grindstone 53.

[0078] In this case, the dresser or the like can also be pressed against the diamond grindstone 53 to perform dressing as necessary.

[0079] According to the mechanical polishing (high-precision grinding) process of the above-mentioned first surface machining step (STEP130 / FIG. 1) and second surface machining step (STEP140 / FIG. 1), any one surface of the transfer-free cut surface with high flatness obtained in the cutting and polishing step is used as the supporting surface (suction surface), and the other surface is sequentially and mechanically polished (high-precision grinding process). Accordingly, this can prevent so-called transfer and obtain high-quality SiC wafers, and can greatly simplify the conventional loose grinding stone process, which is a complicated manufacturing process containing, for example, multiple times of lapping step (from one time to four times).

[0080] More specifically, there is no need to exchange grinding stones for rough grinding and multiple times of fine grinding. For example, it is possible to directly perform a grinding process till fine grinding at once with a #30000 or above grinding stone. Therefore, it is not only simple but also has the advantage of being able to ensure a large amount of usable intrinsic semiconductor layers from the SiC wafer 100.

[0081] Here, in the high-precision grinding processing of the first surface machining step (STEP130 / FIG. 1) and the second surface machining step (STEP140 / FIG. 1), the size of SiC wafer 100 currently reaches 8 inches. However, wafers of various diameters (up to 12 inches) can be set according to the area of the grinding head to perform high-precision grinding processing.

[0082] The above is the details of the method for manufacturing the SiC wafer of the present embodiment. As described above in detail, according to the method and device for manufacturing SiC wafer of the present embodiment, a plurality of wires 42 can be accurately arranged in a plurality of concave grooves 11 with respect to the plurality of concave grooves 11 formed in the entire side surface of the SiC ingot 10 by the groove machining drum grindstone 20, wherein the cut portions of the wires are concentrated on the bottom portion of the concave grooves 11 without the wires 42 being biased to one side surface (for example, one surface in the width direction) of the concave grooves 11 while the concave grooves 11 serve as a guide at the time of cutting, and the SiC ingot 10 can be cut into slices via a plurality of wires 42 at once with high accuracy.

[0083] In addition, in the above embodiment, the pad groove forming process may be changed so that the pad grooves 31 and the pad convex portions 32 have the same shape as the plurality of concave grooves 11 (the plurality of convex portions 21 of the groove machining drum grindstone 20) surrounding the entire side surface of the SiC ingot 10.

[0084] Specifically, it is possible that in the pad groove forming process, a cylindrical pad groove machining grindstone is prepared in advance, and the groove machining drum grindstone 20 and the pad groove machining grindstone are pressed against each other while the groove machining drum grindstone and the semiconductor crystal ingot are rotated respectively on rotation shafts parallel to each other, to form pad machining grooves (pad machining convex portions) corresponding to the plurality of convex portions 21 in the pad groove machining grindstone, and then the pad grooving grindstone and the polishing pad 30 are rotated on rotation shafts parallel to each other, respectively, while the pad groove machining grindstone is pressed against the polishing pad 30a, thereby a plurality of pad grooves corresponding to the pad machining grooves (pad machining convex portions) are formed on the entire side surface of the polishing pad 30.

[0085] Further, in the method of manufacturing the SiC wafer according to the present embodiment, a chemical mechanical polishing (CMP) process or a wafer cleaning process may be performed as necessary after the series of processes described above.

[0086] Further, in the present embodiment, as a method for manufacturing semiconductor crystal wafer, a case where a SiC wafer is manufactured from a SiC ingot has been described, but the semiconductor crystal is not limited to SiC, and may be gallium arsenide, indium phosphide, silicon, or other compound semiconductor.

[0087] Further, in the present embodiment, in the groove machining step (STEP 100 / FIG. 1), the SiC ingot 10 is supported to be freely rotatable while its two end surfaces are protected by a pair of protective plates 15, 15, but the present invention is not limited to as such. For example, the pair of protective plates 15 and 15 may be omitted, and the SiC ingot 10 may be directly fixed to the rotation shaft.

[0088] Further, in a step other than the groove machining step (STEP 100 / FIG. 1), for example, in the polishing step (STEP 110 / FIG. 1) or the cutting step (STEP 120 / FIG. 1), the machining process may be performed in a state where both end surfaces of the SiC ingot 10 are protected by the pair of protective plates 15 and 15.

[0089] In addition, in the present embodiment, as illustrated in FIG. 4, for the positional relationship between the wire saw device 4 and the SiC ingot 10, the SiC ingot 10 is disposed outside the wound wires 42 so that the wires 42 advance outward in the circumferential direction (upward in the drawing), but the present invention is not limited thereto.

[0090] For example, the SiC ingot 10 may be disposed inside the wound wires 42, and the wires 42 may (relatively) move inward in the circumferential direction (downward in the drawing). In this case, the imaging means 44 is disposed on the upper side of the wires 42 (so as to capture an image from directly above to directly below the SiC ingot 10).REFERENCE SIGNS LIST

[0091] 1SiC crystal (semiconductor crystal) 4wire saw device 10SiC ingot (semiconductor crystal ingot) 11concave groove 15protective plate 20groove machining drum grindstone 21convex portion 30polishing pad 31pad groove 32pad convex portion 41bobbin 42wire 43ingot supporting means 44imaging means 45frame 46connection plate (attaching / detaching means) 46'auxiliary connection plate 47slider 50mechanical polishing device (ultra-high synthetic high-precision grinding device) 51spindle 52platen 53diamond grindstone 54porous vacuum chuck (suction plate) 100SiC wafer (semiconductor crystal wafer) 110one surface 120the other surface

Claims

1. A semiconductor crystal wafer manufacturing device which cuts a semiconductor crystal ingot, that has been ground into a cylindrical shape, into slices as wafers, the device comprising: a groove machining drum grindstone configured for forming a plurality of concave grooves surrounding an entire side surface of the semiconductor crystal ingot, wherein a plurality of convex portions corresponding to the plurality of concave grooves are formed on a side surface of the groove machining drum grindstone; and a wire saw device configured for cutting the semiconductor crystal ingot into slices by advancing a plurality of wires disposed in the plurality of concave grooves while making the plurality of wires revolving; an imaging means provided in the wire saw device at a position facing an ingot supporting means that supports the semiconductor crystal ingot across the plurality of wires, so as to image the plurality of wires disposed in the plurality of concave grooves; and a slider provided with the imaging means on a front end side thereof and capable of advancing the imaging means from a frame of the wire saw device to the position where imaging is performed and retracting the imaging means after imaging; wherein a deviation angle of the plurality of wires with respect to the plurality of concave grooves is detected from an image captured by the imaging means.

2. A semiconductor crystal wafer manufacturing device which cuts a semiconductor crystal ingot, that has been ground into a cylindrical shape, into slices as wafers, the device comprising: a groove machining drum grindstone configured for forming a plurality of concave grooves surrounding an entire side surface of the semiconductor crystal ingot, wherein a plurality of convex portions corresponding to the plurality of concave grooves are formed on a side surface of the groove machining drum grindstone; and a wire saw device configured for cutting the semiconductor crystal ingot into slices by advancing a plurality of wires disposed in the plurality of concave grooves while making the plurality of wires revolving; an imaging means provided in the wire saw device at a position facing an ingot supporting means that supports the semiconductor crystal ingot across the plurality of wires, so as to image the plurality of wires disposed in the plurality of concave grooves; a slider provided with the imaging means on a front end side thereof and capable of advancing the imaging means to the position where imaging is performed; and an attaching / detaching means configured for detachably attaching the slider to the wire saw device; wherein a deviation angle of the plurality of wires with respect to the plurality of concave grooves is detected from an image captured by the imaging means.

3. The device of claim 1 or 2, wherein the slider makes the imaging means slide at the position, and the imaging means continuously images the plurality of wires disposed in the plurality of concave grooves.

4. The device of claim 1 or 2, wherein the ingot supporting means includes a deviation angle adjusting means, which is configured to rotate and fix the semiconductor crystal ingot so that the deviation angle detected from the image captured by the imaging means becomes zero.

5. A semiconductor crystal wafer manufacturing method which cuts a semiconductor crystal ingot, that has been ground into a cylindrical shape, into slices as wafers, the method comprising: a groove machining step for forming a plurality of concave grooves surrounding an entire side surface of the semiconductor crystal ingot; and a cutting step performed by a wire saw device, which cuts the semiconductor crystal ingot into slices by advancing a plurality of wires disposed in a plurality of concave grooves formed in the groove machining step while making the plurality of wires revolving; wherein, in the groove machining step, a groove machining drum grindstone in which a plurality of convex portions corresponding to the plurality of concave grooves are formed on a side surface thereof is pressed against the semiconductor crystal ingot while the groove machining drum grindstone and the semiconductor crystal ingot are rotated respectively on rotation shafts parallel to each other to form the concave grooves; and wherein, in the cutting step, before the semiconductor crystal ingot is cut into slices by advancing the plurality of wires disposed in the plurality of concave grooves while making the plurality of wires revolve, a slider provided with an imaging means on a front side thereof is advanced from a frame of the wire saw device, and wherein, at a position facing an ingot supporting means that supports the semiconductor crystal ingot across the plurality of wires, the plurality of wires disposed in the plurality of concave grooves are imaged by the imaging means, and a deviation angle of the plurality of wires with respect to the plurality of concave grooves is detected from a captured image, wherein the deviation angle is adjusted to zero, and the slider is retracted after the deviation angle is adjusted.

6. A semiconductor crystal wafer manufacturing method which cuts a semiconductor crystal ingot, that has been ground into a cylindrical shape, into slices as wafers, the method comprising: a groove machining step for forming a plurality of concave grooves surrounding an entire side surface of the semiconductor crystal ingot; and a cutting step performed by a wire saw device which cuts the semiconductor crystal ingot into slices by advancing a plurality of wires disposed in the plurality of concave grooves formed in the groove machining step while making the plurality of wires revolve; wherein, in the groove machining step, a groove machining drum grindstone in which a plurality of convex portions corresponding to the plurality of concave grooves are formed on a side surface thereof is pressed against the semiconductor crystal ingot while the groove machining drum grindstone and the semiconductor crystal ingot are rotated respectively on rotation shafts parallel to each other to form the concave grooves; and wherein, in the cutting step, before the semiconductor crystal ingot is cut into slices by advancing the plurality of wires disposed in the plurality of concave grooves while making the plurality of wires revolve, a slider provided with an imaging means on a front side thereof is advanced, and wherein, at a position facing an ingot supporting means that supports the semiconductor crystal ingot across the plurality of wires, the plurality of wires disposed in the plurality of concave grooves are imaged by the imaging means, and a deviation angle of the plurality of wires with respect to the plurality of concave grooves is detected from a captured image, wherein the deviation angle is adjusted to zero, and the slider is removed after the deviation angle is adjusted.

7. The method of claim 5 or 6, wherein in the cutting step, prior to the cutting, the ingot supporting means performs a deviation angle adjustment step to rotate and fix the semiconductor crystal ingot so that the deviation angle detected from the image captured by the imaging means becomes zero.

Images