# US 2013/0157009 A1 · Method for forming identification marks on silicon carbide single crystal substrate, and silicon carbide single crystal substrate > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0157009 A1 - Document ID: US20130157009A1 - Status: Published application - Kind: A1 - Application number: 13/817,907 - Filed: 2012-01-05 - Published: 2013-06-20 - Earliest claimed: 2011-01-06 - Assignees: Hitachi Metals, Ltd. - Inventors: Sadahiko Kondo - Web page: https://patentgrep.com/patent/US20130157009A1 ## CPC - H10W 46/00: Marks applied to devices, e.g. for alignment or identification - B23K 26/364: for making a groove or trench, e.g. for scribing a break initiation groove - B23K 26/40: taking account of the properties of the material involved - B41M 3/14: Security printing {(securities B42D25/29)} - B41M 5/24: Ablative recording, e.g. by burning marks; Spark recording {(marking by high energetic means, e.g. by laser otherwise than burning or ablative removal B41M5/26; materials or methods for recording or reproduction by optical means G11B7/00)} - C30B 33/04: using electric or magnetic fields or particle radiation - C30B 33/08: Etching - B23K 2103/50: {Inorganic materials other than metals or composite materials} - Y10T 428/24355: Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.] - Y10T 428/24479: including variation in thickness - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM - B41M: PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING, (correction of typographical errors B41J; processes for applying transfer pictures or the like B44C1/16; fluid media for correction of typographical errors by coating C09D10/00; printing textiles D06P) - C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method for forming an identification mark on a silicon carbide single crystal substrate according to the present invention includes: (a) scanning a principal surface of a silicon carbide single crystal substrate with a laser beam at a first energy density such that a groove is formed in the principal surface of the silicon carbide single crystal substrate, thereby forming an identification mark which is constituted of one or more grooves in the principal surface of the silicon carbide single crystal substrate; and (b) scanning an inside of the groove formed in the principal surface of the silicon carbide single crystal substrate with a laser beam at a second energy density that is lower than the first energy density. ## Claims ### Claim 1 A method for forming an identification mark on a silicon carbide single crystal substrate, comprising: (a) scanning a principal surface of a silicon carbide single crystal substrate with a laser beam at a first energy density such that a groove is formed in the principal surface of the silicon carbide single crystal substrate, thereby forming an identification mark which is constituted of one or more grooves in the principal surface of the silicon carbide single crystal substrate; and (b) scanning an inside of the groove formed in the principal surface of the silicon carbide single crystal substrate with a laser beam at a second energy density that is lower than the first energy density. ### Claim 2 (depends on 1) The method of claim 1, wherein a width of the groove is not less than 50 μm, and a depth of the groove is not less than 20 μm. ### Claim 3 (depends on 1) The method of claim 1 wherein, at least at a bottom surface of an internal surface of the groove, the surface roughness Ra is not more than 1 μm. ### Claim 4 (depends on 1) The method of claim 1, further comprising (c) after step (b), performing mechanical polishing on the principal surface of the silicon carbide single crystal substrate. ### Claim 5 (depends on 4) The method of claim 4 wherein, after step (c), gas phase etching is performed on the principal surface of the silicon carbide single crystal substrate. ### Claim 6 (depends on 1) The method of claim 1, wherein the surface roughness Ra of the principal surface of the silicon carbide single crystal substrate is not less than 0.1 nm and not more than 2.0 nm. ### Claim 7 A silicon carbide single crystal substrate which has an identification mark on a principal surface of the silicon carbide single crystal substrate, the identification mark being constituted of one or more grooves, wherein a width of the groove is not less than 50 μm and less than 0.5 mm, and a depth of the groove is not less than 20 μm, and a surface roughness Ra of an internal surface of the groove is not more than 1 μm. ### Claim 8 (depends on 7) The silicon carbide single crystal substrate of claim 7, wherein the surface roughness Ra of the principal surface is not less than 0.1 nm and not more than 2.0 nm. ### Claim 9 (depends on 7) The silicon carbide single crystal substrate of claim 7, wherein a bottom surface of the groove is a solidified surface. ### Claim 10 (depends on 9) The silicon carbide single crystal substrate of claim 9, wherein the bottom surface of the groove has a striped pattern.