Manufacturing device and manufacturing method for semiconductor crystal wafer

Abstract

The purpose of the present invention is to provide a manufacturing device and a manufacturing method for a semiconductor crystal wafer, wherein a semiconductor crystal wafer of high quality can be easily and reliably manufactured. This manufacturing method for a SiC wafer, which is a semiconductor crystal wafer, comprises a groove machining step (STEP100 / fig. 1), a guideline forming step (STEP110 / fig. 1), a cutting step (STEP120 / fig. 1), and a grinding machining step (STEP130 / fig. 1).

Description

Semiconductor crystal wafer manufacturing apparatus and manufacturing method

[0001] The present invention relates to a semiconductor crystal wafer manufacturing apparatus and method for slicing wafers from a semiconductor crystal ingot that has been ground into a cylindrical shape.

[0002] Conventionally, as a method for manufacturing a SiC wafer, which is this type of semiconductor crystal wafer, as disclosed in Patent Document 1 below, there has been known a method for manufacturing a SiC wafer, which includes, as a wafer shape forming step, an ingot forming step in which a mass of crystal-grown single crystal SiC is processed into a cylindrical ingot, a crystal orientation forming step in which a notch is formed in a part of the outer periphery to serve as a mark indicating the crystal orientation of the ingot, a slicing step in which the single crystal SiC ingot is sliced ​​and processed into thin disk-shaped SiC wafers, a planarizing step in which the SiC wafer is planarized using abrasive grains having a hardness less than the modified Mohs hardness, an imprint forming step in which an imprint is formed, and a chamfering step in which the outer periphery is chamfered, as well as a process-damaged layer removing step in which a process-damaged layer introduced into the SiC wafer in the preceding step is removed, and finally, as a mirror polishing step, a chemical mechanical polishing (CMP) step in which polishing is performed using a combination of the mechanical action of a polishing pad and the chemical action of a slurry.

[0003] Japanese Patent Application Laid-Open No. 2020-15646

[0004] However, such conventional SiC wafer manufacturing methods have the problem that they involve many complicated manufacturing steps, which results in a complicated apparatus configuration and increases manufacturing costs.

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

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a semiconductor crystal wafer manufacturing apparatus and method that can easily and reliably manufacture high-quality semiconductor crystal wafers.

[0007] The semiconductor crystal wafer manufacturing apparatus of the first invention is a semiconductor crystal wafer manufacturing apparatus that cuts wafers into slices from a semiconductor crystal ingot that has been ground into a cylindrical shape, and comprises: a guideline forming means that forms cutting guidelines by scanning a focal point of a laser beam having a wavelength that is transparent to the semiconductor crystal ingot along a planned cutting surface; and a cutting means that cuts the planned cutting surface of the semiconductor crystal ingot, wherein the guideline forming means forms the cutting guidelines as scanning lines that correspond to the cutting direction of the cutting means on the planned cutting surface, and that coincide with the cutting direction of the cutting means.

[0008] According to the semiconductor crystal wafer manufacturing apparatus of the first invention, the cutting guide lines formed on the intended cutting surface act as a guide for cutting when the cutting means is used, so that the semiconductor crystal ingot can be cut into slices with high precision by the cutting means.

[0009] That is, when cutting, the cutting guide line of the cutting means becomes an area with low cutting resistance and serves as a guide for cutting.

[0010] Here, the cutting guideline is formed as a scanning line corresponding to the cutting direction of the cutting means within the intended cutting surface corresponding to the cutting direction of the cutting means (for example, the scanning line may be coincident with the cutting direction, perpendicular to the cutting direction, or the density of the scanning line may vary depending on the cutting direction), so that an area with low cutting resistance can be formed corresponding to the cutting direction when cutting with the cutting means.

[0011] Furthermore, according to the semiconductor crystal wafer manufacturing apparatus of the first invention and the semiconductor crystal wafer manufacturing method of the fifth invention, by forming the cutting guide lines along scanning lines that coincide with the cutting direction of the cutting means, when the cutting means actually cuts, the cutting guide lines, which are areas with low cutting resistance, are formed continuously in the cutting direction and serve as cutting guides.

[0012] In this way, the semiconductor crystal wafer manufacturing apparatus of the first aspect of the invention can accurately cut a semiconductor crystal ingot into slices, and can easily and reliably manufacture high-quality semiconductor crystal wafers.

[0013] The semiconductor crystal wafer manufacturing apparatus of the second invention is the same as that of the first invention, wherein the cutting means is a wire electric discharge machining apparatus that advances a wire while making it circle around the intended cutting surface and generates an electric discharge from the wire.

[0014] According to the semiconductor crystal wafer manufacturing apparatus of the second invention, it is preferable that the cutting means is a wire electric discharge machine, and the semiconductor crystal ingot can be cut into slices with high precision.

[0015] In this way, the semiconductor crystal wafer manufacturing apparatus of the second invention can actually cut a semiconductor crystal ingot into slices with high precision, and can easily and reliably manufacture high-quality semiconductor crystal wafers.

[0016] A third aspect of the present invention provides a semiconductor crystal wafer manufacturing apparatus according to the first aspect, characterized in that the cutting means is a cutter device that advances a cutting blade along the intended cutting surface.

[0017] According to the semiconductor crystal wafer manufacturing apparatus of the third invention, it is preferable that the cutting means is a cutter device, which can accurately cut the semiconductor crystal ingot into slices.

[0018] In this way, the semiconductor crystal wafer manufacturing apparatus of the third invention can actually cut a semiconductor crystal ingot into slices with high precision, and can easily and reliably manufacture high-quality semiconductor crystal wafers.

[0019] A semiconductor crystal wafer manufacturing apparatus according to a fourth aspect of the present invention is an apparatus for cutting wafers into slices from a semiconductor crystal ingot that has been ground into a cylindrical shape, the apparatus comprising: a groove processing drum grindstone for forming a plurality of grooves that go around the entire side of the semiconductor crystal ingot, the groove processing drum grindstone having a plurality of convex portions formed on its side surface corresponding to the plurality of grooves; a wire saw device for cutting the semiconductor crystal ingot into slices by advancing a plurality of wires arranged in the plurality of grooves while moving them around; and guideline forming means for forming cutting guidelines on each planned cutting surface that includes each groove formed on the side of the semiconductor crystal ingot, by scanning a focusing point of a laser beam having a wavelength that is transparent to the semiconductor crystal ingot along the planned cutting surface, the focusing point being formed by focusing a laser beam having a wavelength that is transparent to the semiconductor crystal ingot; the guideline forming means forms the cutting guidelines in a scanning direction that corresponds to the traveling direction of the wire of the wire saw device, and that coincides with the traveling direction of the wire.

[0020] The semiconductor crystal wafer manufacturing apparatus of the fourth invention is configured with a groove processing drum grindstone that forms multiple grooves around the entire side surface of a semiconductor crystal ingot and has multiple protrusions formed on its side surface that correspond to the multiple grooves, and additional equipment that corresponds to this.

[0021] The first additional equipment is a wire saw device that rotates multiple wires arranged in multiple grooves formed on the entire side of a semiconductor crystal ingot.

[0022] The second additional equipment is a guideline forming means that forms cutting guidelines by scanning a laser beam of a wavelength having transparency along each cutting surface, including each groove, at a focal point.

[0023] In the above configuration, multiple wires are accurately positioned in multiple grooves formed on the entire side of the semiconductor crystal ingot by the groove processing drum grinding stone, and cutting guidelines formed on each intended cutting surface act as a cutting guide during cutting with the wires, allowing the semiconductor crystal ingot to be accurately cut into slices using multiple wires.

[0024] That is, when the wire placed in the groove moves forward while circling during cutting, the groove and cutting guide line in the portion before cutting form an area with low cutting resistance, thereby serving as a guide for cutting.

[0025] Furthermore, by forming the cutting guide line in accordance with the direction of wire travel, it is possible to continuously provide the wire with an area of ​​low cutting resistance while the wire is traveling.

[0026] Furthermore, according to the semiconductor crystal wafer manufacturing apparatus of the fourth invention, by forming the cutting guide lines in alignment with the direction of wire travel, it is possible to continuously provide the wire with areas of low cutting resistance while the wire is actually traveling.

[0027] In this way, the semiconductor crystal wafer manufacturing apparatus of the fourth aspect of the invention makes it possible to cut a semiconductor crystal ingot into slices with high precision, and to easily and reliably manufacture high-quality semiconductor crystal wafers.

[0028] A semiconductor crystal wafer manufacturing apparatus according to a fifth aspect of the present invention is any one of the first to fourth aspects of the present invention, characterized in that the guideline forming means causes the laser beam to be incident on an end face of the semiconductor crystal ingot.

[0029] According to the semiconductor crystal wafer manufacturing apparatus of the fifth invention, the laser beam for forming the cutting guideline is incident on the end face of the semiconductor crystal ingot, and the distance to the focal point is determined and the wire is scanned along the direction of travel while maintaining that distance, thereby making it possible to easily and reliably form the cutting guideline.

[0030] In this way, according to the semiconductor crystal wafer manufacturing apparatus of the fifth invention, cutting guidelines can be easily and reliably formed, and the semiconductor crystal ingot can be accurately cut into slices, making it possible to easily and reliably manufacture high-quality semiconductor crystal wafers.

[0031] A sixth aspect of the present invention relates to a method for manufacturing a semiconductor crystal wafer, which involves cutting wafers into slices from a semiconductor crystal ingot that has been ground into a cylindrical shape, and includes a guideline forming step of forming cutting guidelines by scanning a focused point of a laser beam having a wavelength that is transparent to the semiconductor crystal ingot along a planned cutting surface, and a cutting step of cutting the planned cutting surface of the semiconductor crystal ingot, wherein the guideline forming step forms the cutting guidelines as scanning lines that correspond to the cutting direction of the cutting step on the planned cutting surface, and that coincide with the cutting direction of the cutting step.

[0032] According to the method for manufacturing a semiconductor crystal wafer of the sixth aspect of the present invention, the cutting guide lines formed on the intended cutting surface serve as a guide for cutting during the cutting step, and therefore the semiconductor crystal ingot can be cut into slices with high precision during the cutting step.

[0033] That is, in the cutting step, the cutting guide line becomes an area with low cutting resistance during cutting and serves as a guide for cutting.

[0034] Here, the cutting guideline is formed as a scanning line corresponding to the cutting direction of the cutting process within the intended cutting surface corresponding to the cutting direction of the cutting process (for example, the cutting direction can be coincident with the cutting direction, perpendicular to the cutting direction, or the density of the scanning line can be varied depending on the cutting direction), so that an area with low cutting resistance can be formed corresponding to the cutting direction when cutting in the cutting process.

[0035] Furthermore, according to the semiconductor crystal wafer manufacturing method of the sixth aspect of the invention, by forming the cutting guide lines along scanning lines that coincide with the cutting direction of the cutting step, the cutting guide lines, which are areas of low cutting resistance during actual cutting in the cutting step, are formed continuously in the cutting direction and serve as cutting guides.

[0036] Thus, according to the method for producing a semiconductor crystal wafer of the sixth aspect of the invention, it is possible to cut a semiconductor crystal ingot into slices with high precision, and to easily and reliably produce high-quality semiconductor crystal wafers.

[0037] A seventh aspect of the present invention relates to a method for manufacturing a semiconductor crystal wafer, which involves cutting wafers into slices from a semiconductor crystal ingot that has been ground into a cylindrical shape, and includes: a groove processing step of forming a plurality of grooves that go around the entire side surface of the semiconductor crystal ingot; a guideline forming step of forming cutting guidelines by scanning, along each planned cutting surface including each groove formed on the side surface of the semiconductor crystal ingot by the groove processing step, a focusing point of a laser beam having a wavelength that is transparent to the semiconductor crystal ingot; and a cutting step of cutting the semiconductor crystal ingot into slices by advancing a plurality of wires disposed in the plurality of grooves formed in the groove processing step while making them go around, wherein the guideline forming step forms the cutting guidelines in a scanning direction that corresponds to the direction of travel of the wires in the cutting step.

[0038] According to the semiconductor crystal wafer manufacturing method of the seventh invention, the following steps are carried out: a groove processing step in which grooves corresponding to the multiple convex portions of the groove processing drum are formed on the entire side surface of the semiconductor crystal ingot; a guideline forming step in which cutting guidelines are formed on each of the intended cutting surfaces including the multiple grooves formed in the groove processing step; and a cutting step in which the semiconductor crystal ingot is cut into slices by advancing and circulating multiple wires disposed in the multiple grooves formed in the groove processing step.

[0039] Here, multiple wires are accurately positioned in multiple grooves formed across the entire side surface of the semiconductor crystal ingot by the groove processing drum grinding stone, and cutting guidelines formed on each intended cutting surface act as a guide for cutting during cutting with the wires, allowing the semiconductor crystal ingot to be accurately cut into slices using multiple wires.

[0040] That is, when the wire placed in the groove moves forward while circling during cutting, the groove and cutting guide line form an area with low cutting resistance, which serves as a guide for cutting.

[0041] Furthermore, by forming the cutting guide line in correspondence with the direction of wire travel, it is possible to continuously provide the wire with areas of low cutting resistance while the wire is traveling.

[0042] Thus, according to the semiconductor crystal wafer manufacturing method of the seventh aspect of the invention, it is possible to cut a semiconductor crystal ingot into slices with high precision, and to easily and reliably manufacture high-quality semiconductor crystal wafers.

[0043] Fig. 2 is a flowchart showing all steps in a method for manufacturing a SiC wafer (semiconductor crystal wafer) according to the present embodiment. Fig. 3 is an explanatory diagram showing the details of a groove processing step in the method for manufacturing a SiC wafer of Fig. 1. Fig. 4 is an explanatory diagram showing the details of a guideline forming step and a cutting step in the method for manufacturing a SiC wafer of Fig. 1. Fig. 5 is an explanatory diagram showing the details of a grinding step in the method for manufacturing a SiC wafer of Fig. 1. Fig. 6 is an explanatory diagram showing a modified example of the guideline forming step in the method for manufacturing a SiC wafer of Fig. 1. Fig. 7 is an explanatory diagram showing a modified example of the guideline forming step in the method for manufacturing a SiC wafer of Fig. 1.

[0044] As shown in FIG. 1 , in this embodiment, the method for manufacturing a SiC wafer, which is a semiconductor crystal wafer, is a method for obtaining SiC wafers by slicing them from a SiC ingot that has been ground into a cylindrical shape, and includes a groove processing step (STEP 100 / FIG. 1), a guideline formation step (STEP 110 / FIG. 1), a cutting step (STEP 120 / FIG. 1), and a grinding step (STEP 130 / FIG. 1).

[0045] The details of each step and the SiC wafer manufacturing apparatus of this embodiment will be described with reference to FIGS.

[0046] First, in the groove processing step (STEP 100 / FIG. 1), a common groove processing drum grindstone 20 is used to form a plurality of recessed grooves 11 around the entire side surface of the SiC ingot 10.

[0047] The groove processing drum grinding wheel 20 is a drum grinding wheel for forming a plurality of grooves 11 that run around the entire side surface of the SiC ingot 10, and has a plurality of protrusions 21 formed on the side surface corresponding to the plurality of grooves 11.

[0048] Specifically, in the groove processing step (STEP 100 / Figure 1), groove processing drum grinding wheels 20, each having a plurality of protrusions 21 corresponding to the plurality of grooves 11 formed on the entire side, are rotated on mutually parallel rotation axes while being pressed against the SiC ingot 10 to form the grooves 11.

[0049] At this time, the SiC ingot 10 is rotatably supported with both end faces thereof protected by a pair of protective plates 15, 15.

[0050] The protective plate 15 is made of a synthetic resin such as polyvinyl chloride, and is bonded to the SiC ingot 10 via an adhesive or the like as needed.

[0051] The pair of protective plates 15 protects both ends of the SiC ingot 10 and prevents chipping or cracking at both ends. This allows the formation of multiple grooves 11 up to the edges of both end faces, thereby enabling a larger number of SiC wafers 100 (described later) to be cut and obtained.

[0052] Furthermore, when the SiC ingot 10 is clamped and fixed to the rotating shaft, the protective plates 15, 15 can be processed (for example, drilled) to fix the SiC ingot 10 as needed. In addition, since no processing of the SiC ingot 10 itself is involved in this case either, the SiC ingot 10 is not damaged.

[0053] Next, as shown in FIG. 3A, prior to cutting with the wire 40, cutting guidelines are formed on the intended cutting surface in a guideline forming step (STEP 110 / FIG. 1).

[0054] The intended cutting surface is a surface including each groove 11 formed in the groove processing step (STEP 100 / FIG. 1) (a circular surface shown by an imaginary line in the drawing, which is smaller than the outer diameter of the ingot by the width of the groove). By positioning a focal point of a laser beam having a wavelength that is transparent to SiC ingot 10 on the intended cutting surface, modified regions of SiC crystal are partially formed in SiC ingot 10. Then, a desired cutting guideline is formed by scanning the focal point across the intended cutting surface along a scanning line.

[0055] The guideline means for forming such cutting guideline includes a laser oscillator for emitting the laser beam and a condenser (lens) for condensing the laser beam inside the SiC ingot 10.

[0056] Specifically, as shown in the cross-sectional view of the intended cutting surface in Fig. 3(b), multiple cutting guide lines are formed by scanning multiple times in the direction of travel of the wire 40, as indicated by the arrows in the figure. The spacing between these cutting guide lines may be uniform, but they may also be spaced apart so that the spacing becomes smaller toward the center and becomes larger toward both the left and right sides.

[0057] By providing such a density variation, the cutting speed slows down in the center where the amount of cutting is greater as the wire 40 advances (conversely, the cutting speed increases on both sides), causing the wire 40 to curve. However, by providing areas with low cutting resistance in stages from both sides to the center, the wire 40 can be prevented from curving and kept straight, as shown in Figure 3(c).

[0058] The wire device used in the cutting process using such wire 40 (STEP 120 / Figure 1) (various devices can be used) advances and rotates multiple wires 40 passed between wire bobbins, and applies a high voltage (high frequency high voltage) to the wire to discharge electricity into the SiC ingot 10, thereby cutting the SiC ingot 10 into slices.

[0059] When the wire 40 placed in the groove 11 moves forward while circling and discharging during cutting, in addition to the groove 11 (which reduces the outer diameter of the SiC ingot 10), the cutting guideline makes the surface to be cut an area with low cutting resistance, allowing the wire 40 to slide across the surface to be cut.

[0060] This allows the SiC ingot 10 to be precisely sliced ​​into slices in one go using the multiple wires 40 arranged in the multiple grooves 11. That is, high-speed cutting can be achieved using the wires 40, and the cut surface can be flat and low-damage processed. In addition, even SiC ingots 10 with poor crystallinity in the entire surface or specific regions can be sliced ​​to a specified thickness, without being affected by crystal orientation.

[0061] Furthermore, since the cutting resistance is small, the diameter of the wire 40 itself can be made small, and as a result, the cutting allowance can be minimized and the yield can be improved.

[0062] Next, as shown in FIG. 4, in the grinding process (STEP 130 / FIG. 1), in the first surface processing process (STEP 130(1)), one of the cut surfaces 110 is used as a support surface, and the remaining other surface 120 is subjected to mechanical polishing (high-precision grinding).

[0063] Specifically, in the first surface processing step (STEP 130(1)), grinding is performed by a mechanical polishing device 50 (ultra-high synthesis, high precision grinding device) that performs mechanical polishing.

[0064] The mechanical polishing device 50 includes a spindle 51 and a diamond grinding wheel 53 on a platen 52 serving as a surface plate.

[0065] First, the first surface 110 is set as the upper surface and supported by the vacuum porous chuck 54 which is the suction plate of the spindle 51 , and the second surface 120 is set as the lower surface and is ground by the diamond grindstone 53 .

[0066] At this time, the spindle 51 and the diamond grinding wheel 53 are rotated by a drive device (not shown), and the spindle 51 is pressed against the diamond grinding wheel 53 by a compressor (not shown) or the like, thereby grinding the other surface 120.

[0067] After the grinding process, the diamond grinding wheel 53 may be dressed using a dresser or the like.

[0068] Furthermore, the mechanical polishing device 50 may have a functional water supply pipe so that multiple types of functional water can be used during processing, if necessary.

[0069] Next, in the second surface processing step (STEP 130 (2)), the other surface 120 that has been subjected to high-precision grinding in the first surface processing step is used as the upper surface, and high-precision grinding similar to that in the first surface processing step is performed on the one surface 110.

[0070] That is, the other surface 120 is attached to a vacuum porous chuck 54 which is an attachment plate of the spindle 51 with the other surface 120 as the upper surface, and the one surface 110 is ground with the diamond grindstone 53 with the one surface 110 as the lower surface.

[0071] In this case, too, dressing may be performed by pressing a dresser or the like against the diamond grinding wheel 53, if necessary.

[0072] According to the mechanical polishing (high-precision grinding) treatment in the first surface processing step (STEP 130(1)) and the second surface processing step (STEP 130(2)), one of the transferless cut surfaces having high flatness obtained in the cutting and polishing step is used as a support surface (adsorption surface), and the remaining surfaces are sequentially subjected to mechanical polishing (high-precision grinding). This makes it possible to prevent so-called transfer and obtain high-quality SiC wafers, and also makes it possible to significantly simplify the complicated manufacturing process such as conventional free grinding stone processing, i.e., multiple lapping steps from the first to fourth stages.

[0073] More specifically, there is no need to change grinding stones to perform rough grinding or multiple finish grinding operations. For example, finishing can be performed directly in one grinding operation using a grinding stone of #30000 or higher. This is not only simple, but also has the advantage of being able to ensure a large intrinsic semiconductor layer that can be used from SiC wafer 100.

[0074] In the high-precision grinding process of the first surface processing step (STEP 130(1)) and the second surface processing step (STEP 130(2)), the size of the SiC wafer 100 is currently up to 8 inches, and wafers of each diameter are set according to the area of ​​the head (up to 12 inches are possible), and high-precision grinding process is performed.

[0075] The above is the details of the SiC wafer manufacturing method of this embodiment. As described above in detail, according to the SiC wafer manufacturing method and apparatus of this embodiment, by proactively forming regions with low cutting resistance using grooves 11 and cutting guidelines, these act as cutting guides, and SiC ingot 10 can be accurately sliced ​​into slices in one go using multiple wires 40.

[0076] Next, an example of a modification of the cutting guide line will be described with reference to FIG.

[0077] Specifically, as shown in Fig. 5(a), the cutting guide lines are not limited to the end surface of the SiC ingot 10. By irradiating a laser beam from the side, a plurality of cutting guide lines may be formed concentrically on the intended cutting surface, as shown in the cross-sectional view of the intended cutting surface in Fig. 5(b). For example, concentric cutting guide lines can be easily formed by rotating the SiC ingot 10 around its axis.

[0078] In this case, too, when the wire 40 disposed in the groove 11 moves forward while circling during cutting, the groove 11 in the uncut region and the cutting guide lines also function as regions of low cutting resistance, and serve as cutting guides. Also in this case, the multiple concentric cutting guide lines are denser toward the center of the SiC ingot 10, so that the wire 40 can be prevented from bowing and kept straight, as shown in FIG. 5( c).

[0079] In the above embodiment, the cutting guidelines are not limited to being aligned with the advancing direction of the wire 40 or being formed concentrically. The cutting guidelines may be formed in any manner as long as they take into account the advancing direction of the wire 40, and may be formed, for example, with the cutting end point of the wire 40 as the starting point and in a scanning direction that radiates in the advancing / retreating direction of the wire (the retracting direction in this case).

[0080] In this case, too, the cutting guidelines are denser in the center of the SiC ingot than on the left and right sides, so areas with low cutting resistance are gradually provided from both sides to the center, preventing the wire 40 from becoming curved and keeping the wire straight.

[0081] Of course, instead of or in addition to being radially aligned from the cutting end point of the wire 40, the cutting guidelines may be formed in a scanning direction that is radially aligned from the cutting start point in the direction of advancement and retreat of the wire (in this case, the direction of advancement).

[0082] In this way, by providing radial cutting guidelines originating from the start point and the end point of the cut, cutting at the start point and the end point of the cut can be performed with almost no cutting resistance, thereby significantly improving the cutting finish at these start point and end point of the cut.

[0083] Furthermore, the guideline formation step (STEP 110 / FIG. 1) of this embodiment may be applied to thin film processing for forming a backside for the purpose of wafer reclamation.

[0084] In the method for manufacturing a SiC wafer according to this embodiment, after the series of processes described above, a chemical mechanical polishing (CMP) step and a wafer cleaning step may be carried out as necessary.

[0085] Furthermore, in this embodiment, a method for manufacturing a semiconductor crystal wafer has been described in which a SiC wafer is manufactured from a SiC ingot, but the semiconductor crystal is not limited to SiC, and may be gallium phosphate, indium phosphide, silicon, or other compound semiconductors.

[0086] In the present embodiment, in the groove machining step (STEP 100 / FIG. 1), the SiC ingot 10 is rotatably supported with both end faces protected by a pair of protective plates 15, 15. However, the present invention is not limited to this. For example, the pair of protective plates 15, 15 may be omitted, and the SiC ingot 10 may be fixed directly to the rotating shaft.

[0087] Furthermore, in processes other than the groove processing process (STEP 100 / Figure 1), for example, the cutting process (STEP 120 / Figure 1), the processing may be performed while both end surfaces of the SiC ingot 10 are protected by a pair of protective plates 15, 15.

[0088] In this embodiment, the groove processing step (STEP 100 / Figure 1) is described as a case in which a common groove processing drum grinding stone 20 is used to form multiple grooves 11 around the entire side surface of the SiC ingot 10, but the groove processing step of STEP 100 may be omitted and no grooves 11 may be formed.

[0089] In addition, in the present embodiment, an electric discharge machining device, which is an electric discharge wire saw device, has been described as an example of the cutting means, but the cutting means is not limited to this and may be a wire saw device without an electric discharge function, or a cutter device (including those with an electric discharge function). In this case, the shape of the cutting blade may be a disk-shaped ring blade, a hacksaw blade, or the like.

[0090] Furthermore, in this embodiment, the cutting guide lines formed in the guideline formation process (STEP 110 / Figure 1) have been mainly described as scanning lines that correspond to the cutting direction, but the scanning lines that correspond to the cutting direction are not limited to this, and in addition to scanning lines that are perpendicular to the cutting direction, scanning lines may be made sparse or dense in accordance with the cutting direction.

[0091] For example, as shown in Fig. 6, cutting guidelines may be formed as radial scanning lines starting from the cutting end point of the cutting means (the wire of the wire saw device) and extending in the cutting direction (the direction of wire travel). By forming the scanning lines radially in this way, for example, regions with low cutting resistance are gradually provided from both sides to the center during cutting, which prevents the center of the wire from being fed in a bow shape in the cutting region, and because the final cut portion is a radial point (which allows cutting without cutting resistance), the finish of the final cut portion is excellent.

[0092] In addition to or instead of starting from the cutting end point of the cutting means (the wire of the wire saw device), such radial scanning lines may start from the cutting start point. In this case, the cutting start point is a radiation point (which allows cutting without cutting resistance), resulting in an excellent finish at the cutting start point.

[0093] 1...SiC crystal (semiconductor crystal), 4...wire saw device (electric discharge machining device), 10...SiC ingot (semiconductor crystal ingot), 11...groove, 15, 15...pair of protective plates, 20...groove processing drum grinding stone, 21...protrusion, 40...wire, 50...mechanical polishing device (ultra-high synthesis high precision grinding processing device), 51...spindle, 52...platen, 53...diamond grinding stone, 54...vacuum porous chuck (suction plate), 100...SiC wafer (semiconductor crystal wafer), 110...one side, 120...other side.

Claims

1. A semiconductor crystal wafer manufacturing apparatus for cutting wafers into slices from a semiconductor crystal ingot that has been ground into a cylindrical shape, comprising: a guideline forming means for forming cutting guidelines by scanning a focused point of a laser beam having a wavelength that is transparent to the semiconductor crystal ingot along a surface to be cut; and a cutting means for cutting the surface to be cut of the semiconductor crystal ingot, wherein the guideline forming means forms the cutting guidelines as scanning lines that correspond to the cutting direction of the cutting means on the surface to be cut and that coincide with the cutting direction of the cutting means.

2. An apparatus for manufacturing semiconductor crystal wafers according to claim 1, wherein the cutting means is a wire electric discharge machining device which advances a wire around the intended cutting surface while generating an electric discharge from the wire.

3. The semiconductor crystal wafer manufacturing apparatus according to claim 1, wherein the cutting means is a cutter device which advances a cutting blade along the intended cutting surface.

4. A semiconductor crystal wafer manufacturing apparatus for cutting wafers into slices from a semiconductor crystal ingot ground into a cylindrical shape, comprising: a groove processing drum grindstone for forming a plurality of grooves that go around the entire side surface of the semiconductor crystal ingot, the groove processing drum grindstone having a plurality of convex portions formed on the side surface corresponding to the plurality of grooves; a wire saw apparatus for cutting the semiconductor crystal ingot into slices by advancing a plurality of wires arranged in the plurality of grooves while moving them around; and guideline forming means for forming cutting guideline by scanning a focusing point of a laser beam having a wavelength that is transparent to the semiconductor crystal ingot along each planned cutting surface including each of the grooves formed on the side surface of the semiconductor crystal ingot, wherein the guideline forming means forms the cutting guideline in a scanning direction that corresponds to the traveling direction of the wire of the wire saw apparatus and that coincides with the traveling direction of the wire.

5. An apparatus for manufacturing semiconductor crystal wafers according to any one of claims 1 to 4, wherein said guide line forming means causes said laser beam to be incident on an end face of said semiconductor crystal ingot.

6. A method for manufacturing a semiconductor crystal wafer, in which wafers are cut into slices from a semiconductor crystal ingot ground into a cylindrical shape, comprising: a guideline forming step of forming cutting guidelines by scanning a focused point of a laser beam having a wavelength that is transparent to the semiconductor crystal ingot along a surface to be cut; and a cutting step of cutting the surface to be cut of the semiconductor crystal ingot, wherein the guideline forming step forms the cutting guidelines on the surface to be cut as scanning lines corresponding to the cutting direction of the cutting step and coinciding with the cutting direction of the cutting step.

7. A method for manufacturing a semiconductor crystal wafer, in which wafers are cut into slices from a semiconductor crystal ingot ground into a cylindrical shape, comprising: a groove processing step of forming a plurality of grooves encircling an entire side surface of the semiconductor crystal ingot; a guideline forming step of forming cutting guidelines by scanning along each planned cutting surface, including each groove formed on the side surface of the semiconductor crystal ingot by the groove processing step, a focusing point of a laser beam having a wavelength that is transparent to the semiconductor crystal ingot, to form cutting guidelines; and a cutting step of cutting the semiconductor crystal ingot into slices by advancing a plurality of wires disposed in the plurality of grooves formed in the groove processing step while rotating them, wherein in the guideline forming step, the cutting guidelines are formed in a scanning direction that corresponds to the traveling direction of the wires in the cutting step and that coincides with the traveling direction of the wires.

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