Ingot manufacturing method

Abstract

Provided is a method for manufacturing an ingot in which defects at corners are easily removed. A method for manufacturing an ingot includes a chamfering step of chamfering a corner portion of an outer peripheral edge of an end surface of a cylindrical ingot in a circumferential direction.

Description

Technical Field The present invention relates to a method for manufacturing an ingot. Background Art There is known a method for manufacturing an ingot in which the corners of a prismatic ingot are chamfered (see, for example, Patent Document 1). Prior art literature Patent Literature Patent Document 1: Japanese Patent No. 3973843 Patent document 2: International Publication No. 2019 / 102629. Summary of the invention The corners of the ingot produced by the cutting step are prone to defects such as chipping and cracks. Therefore, it is necessary to chamfer the corners of the ingot. However, in the past, the corners of the prismatic ingot were chamfered, so there was still an angular portion when the ingot was observed in the height direction after chamfering, so defects were likely to remain in this portion. In view of the above, an object of the present invention is to provide a method for producing an ingot that can easily remove defects at corners. One aspect of the present invention is as follows.

[0001] A method for manufacturing an ingot includes a chamfering step of chamfering corners of an outer peripheral edge of an end face of a cylindrical ingot in a circumferential direction.

[0002] The ingot manufacturing method according to [1] includes an inspection step of inspecting the corner portion chamfered in the chamfering step.

[0003] The method for manufacturing an ingot according to [2] comprises a removing step, wherein the removing step is performed to remove the corner of the ingot to a predetermined depth or to remove the entire end face to a predetermined depth when the removing step is determined to be necessary based on the result of the inspecting step.

[0004] According to the ingot manufacturing method described in [3], the corner removal is performed by the chamfering step again.

[0005] According to the ingot manufacturing method described in [4], the corner removal is performed under specified conditions, and the specified conditions are that the length of the total chamfering amount until the corner removal is completed is less than 3 mm with respect to each side of the corner before chamfering.

[0006] The ingot manufacturing method according to any one of [3] to [5], wherein the end surface removal is performed by cutting the ingot.

[0007] The ingot manufacturing method according to any one of [1] to [6], wherein the first chamfering step is performed under the following conditions: the length of the chamfering amount is 0.5 mm to 1.0 mm with respect to each side of the corner portion before chamfering.

[0008] In the method for manufacturing an ingot according to any one of [1] to [7], the chamfer formed by the chamfering step is a C-chamfer. According to the present invention, it is possible to provide a method for producing an ingot in which defects at corners can be easily removed. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 This is a flowchart showing a method for producing an ingot according to one embodiment of the present invention. Figure 2 It is shown Figure 1 Schematic diagram of the condition of the chamfering step in the ingot manufacturing method shown. Figure 3 It is shown Figure 1 A schematic diagram of the chamfered corner of an ingot is shown. DETAILED DESCRIPTION Hereinafter, embodiments of the present invention will be described by way of example with reference to the accompanying drawings. like Figure 1 to Figure 3 As shown, in one embodiment of the present invention, the method for manufacturing the ingot 1 includes a chamfering step S2, wherein the chamfering step S2 is performed along any side ( Figure 2 The outer peripheral corner 1b of the end face 1a of the cylindrical ingot 1 is chamfered in the direction indicated by the arrow in the figure. The circumferential direction refers to the direction around the central axis O of the cylindrical ingot 1. The circumferential chamfering in the chamfering step S2 is performed by utilizing the circumferential relative rotation of the corner 1b and the grinding tool (not shown), for example, as shown in FIG. Figure 1 As shown, the chamfering is performed by bringing the grinding tool into contact with the corner portion 1 b while rotating the ingot 1 in the circumferential direction. Alternatively, the chamfering may be performed while fixing the ingot 1 and moving the grinding tool in the circumferential direction. According to the above scheme, the ingot 1 is formed into a cylindrical shape, so that the corner 1b is smoothly continuous in the circumferential direction, and there is no angular part when the ingot 1 is observed in the axial direction after chamfering. Moreover, the ingot 1 is formed into a cylindrical shape, so that the chamfering can be easily performed by utilizing the relative rotation of the corner 1b and the grinding tool in the circumferential direction. Therefore, a method for manufacturing the ingot 1 that can easily remove defects in the corner 1b can be realized. In addition, the axial direction refers to the direction along the central axis O, which is the height direction of the cylinder. The grinding tool is not particularly limited, and is, for example, a grinder. The grinder has a grinding wheel, such as a diamond disc type, which has a processing surface pushed to the corner 1b and is driven to rotate around a rotation axis perpendicular to the processing surface. The driving method of the grinding wheel is not particularly limited, and is, for example, an electrical type. The chamfering of the corner 1b can be as follows Figure 2The holding device 2 is used as shown, and the holding device 2 holds the ingot 1 so that it can rotate in the circumferential direction. The holding device 2 can also be as Figure 2 As shown in FIG. 1 , the rotating body 2a is configured to have a plurality of rotating bodies 2a arranged side by side in the circumferential direction. The rotating body 2a can be as follows Figure 2 As shown, it is composed of a roller that can rotate around an axis P parallel to the central axis O of the ingot 1. The holding device 2 can be configured to have a driving device (not shown) that rotates and drives at least one rotating body 2a. The holding device 2 may not have a driving device, and a person or a robot may chamfer the ingot 1 while rotating the ingot 1 while the holding device 2 is holding the ingot 1. According to the above scheme, by using the holding device 2, easier chamfering can be achieved. The manufacturing method of the ingot 1 includes an inspection step S3, which inspects the corner 1b chamfered by the chamfering step S2. In the case where a defect appears at the corner 1b at the millimeter level, it can be found by visual inspection without using an X-ray device or the like, or by appearance inspection using equipment, but in the case where the defect extends to the inside of the ingot at the micron level, it is difficult to find it directly by appearance inspection. According to the above scheme, by virtue of the mechanical damage caused by grinding to the corner 1b due to chamfering, defects such as cracks that are hidden in the corner 1b and become difficult to find can be made obvious, so that simple and low-cost defect discovery by appearance inspection can be achieved. Moreover, it is possible to suppress the defect from becoming obvious in the subsequent process, so that the occurrence of production loss due to unnecessary processing can be suppressed. The manufacturing method of the ingot 1 includes a removal step S4, which is to remove the corner 1b of the ingot 1 to a specified depth or to remove the end face 1a as a whole to a specified depth, if it is determined to be necessary based on the result of the inspection step S3. The criterion for judging whether removal is necessary is not particularly limited, and a known criterion can be used. The specified depth refers to the depth perpendicular to the surface of the chamfered corner 1b in the case of corner removal, and the depth (axial direction) perpendicular to the end face 1a in the case of end face removal. According to the above scheme, the defect of the corner 1b found in the inspection step S3 can be removed by the removal step S4. The corner removal is performed by the re-chamfering step S2. According to the above scheme, the corner removal can be easily performed. After the re-chamfering step S2, the re-inspection step S3 can be performed. Corner removal is performed under prescribed conditions, and the prescribed conditions are that the length of the total chamfering amount until the end of the corner removal is less than 3 mm with respect to each side of the corner 1b before the chamfering is formed. That is, under the above prescribed conditions, the length L1 of the total chamfering amount on the side formed by the outer peripheral surface 1c and the length L2 of the total chamfering amount on the side formed by the end surface 1a are each less than 3 mm. According to the above scheme, corner removal can be performed under the above prescribed conditions without the total chamfering amount becoming too large. The end surface removal is performed by cutting the ingot 1. According to the above scheme, the end surface removal can be easily performed. Figure 1 As shown, the method for manufacturing the ingot 1 includes a cutting step S1 of forming a cylindrical ingot 1 as a target of the chamfering step S2 by cutting, and the end surface removal in the removal step S4 can be configured to be performed by means of a second cutting step S1. In addition, the second cutting step S1 forms a cylindrical ingot 1 as a target of the second chamfering step S2 performed later by cutting. The manufacturing method of the ingot 1 is as follows: if no defect is found in the inspection step S3, the ingot 1 inspected in the inspection step S3 is used as a finished product; if a defect is found in the inspection step S3, the removal step S4 and the subsequent inspection step S3 are repeatedly performed as needed until no defect is found in the corner 1b in the inspection step S3. According to the above scheme, the ingot 1 without defects in the corner 1b can be sent to the subsequent process. The removal step S4 is to remove the corner under the above-mentioned conditions when the defect is found in the inspection step S3, and to remove the end face when the defect found in the inspection step S3 cannot be completely removed. According to the above scheme, effective defect removal can be achieved. In addition, the amount of corner removal in each removal step S4 can be set in advance, or the amount of corner removal can be adjusted by a person or a computer (artificial intelligence, etc.) based on the size of the defect (crack, etc.) found in the inspection step S3. The removal step S4 has a judgment step S4a. When a defect is found in the inspection step S3, the judgment step S4a judges whether it is possible to completely remove the defect by performing corner removal under the above-mentioned conditions. When the judgment step S4a judges that the removal process is possible, the corner removal is performed. When the judgment step S4a judges that the removal process is impossible, the end face removal is performed. According to the above scheme, more effective defect removal can be achieved. The judgment method in the judgment step S4a is not particularly limited. For example, a person or a computer (artificial intelligence, etc.) can judge based on the size of the defect found in the inspection step S3. The algorithm used for judgment is not particularly limited. Sometimes, after performing corner removal based on the judgment in the judgment step S4a, the corner removal is performed according to the result in the inspection step S3. That is, the accuracy of the judgment in the judgment step S4a is not particularly limited. The initial chamfering step S2 is performed under the following conditions: the length of the chamfering amount is 0.5 mm or more and 1.0 mm or less with respect to each side of the corner portion 1b before chamfering. That is, under this condition, the length L1 of the chamfering amount on the side formed by the outer peripheral surface 1c and the length L2 of the chamfering amount on the side formed by the end surface 1a are each 0.5 mm or more and 1.0 mm or less. According to the above scheme, the initial chamfering step S2 can be performed under this condition that the chamfering amount does not become too large. The chamfer formed by the chamfering step S2 is a C-chamfer. According to the above configuration, the corner portion 1b can be easily chamfered. The ingot 1 is a silicon single crystal block (e.g., a diameter of 100 mm to 450 mm, a length of 50 mm to 500 mm, and a weight of 100 kg or less). The silicon single crystal block is hard and brittle, so defects are easily generated at the corner 1b formed by the cutting step S1. According to the above scheme, a method for manufacturing a silicon single crystal block that can easily remove defects at the corner 1b can be realized. The cylindrical ingot 1 has a corner 1b formed at one axial end and a corner 1b formed at the other axial end. The above series of steps for removing defects of the corner 1b are preferably applied to both corners 1b, but may be applied to only one of them. Although the embodiments of the present invention have been described above, the present invention is not limited to the aforementioned embodiments, and the aforementioned embodiments can be variously modified within the scope not departing from the gist of the present invention. Description of Reference Numerals 1 Ingot 1a End face 1b Corner 1c Outer surface 2 Holding device 2a Rotating body S1 Cutting Steps S2 Chamfering Steps S3 Inspection steps S4 Removal Step S4a Judgment Steps L1 The length of the side formed by the outer peripheral surface L2 The length of the side formed by the end faces O Center axis P axis.

Claims

1. A method for manufacturing an ingot, comprising the step of chamfering a corner portion of an outer peripheral edge of an end face of a cylindrical ingot in a circumferential direction.

2. The method for manufacturing an ingot according to claim 1, characterized in that: An inspection step is provided for inspecting the corner portion chamfered by the chamfering step.

3. The method for manufacturing an ingot according to claim 2, characterized in that: A removing step is provided, wherein, when it is determined to be necessary based on the result of the inspecting step, corner removal is performed to remove the corner of the ingot to a predetermined depth or end surface removal is performed to remove the entire end surface to a predetermined depth.

4. The method for manufacturing an ingot according to claim 3, characterized in that: The corner removal is performed by performing the chamfering step again.

5. The method for manufacturing an ingot according to claim 4 is characterized in that the corner removal is carried out under specified conditions, and the specified conditions are that the length of the total chamfering amount until the corner removal is completed is less than 3 mm with respect to each side of the corner before chamfering.

6. The method for manufacturing an ingot according to claim 3, characterized in that: The end surface removal is performed by cutting the ingot.

7. The method for manufacturing an ingot according to claim 1, characterized in that: The first chamfering step is performed under the condition that the length of the chamfering amount is 0.5 mm or more and 1.0 mm or less with respect to each side of the corner portion before chamfering.

8. The method for manufacturing an ingot according to claim 1, characterized in that: The chamfer formed by the chamfering step is a C-chamfer.

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