# US 11,993,822 B2 · Monocrystalline metal foil and manufacturing method therefor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,993,822 B2 - Document ID: US11993822B2 - Status: Granted - Kind: B2 - Application number: 16/767,751 - Filed: 2018-12-13 - Published: 2021-01-07 - Granted: 2024-05-28 - Earliest claimed: 2017-11-28 - Assignees: Institute for Basic Science; Unist (Ulsan National Institute of Science and Technology) - Applicants: Institute for Basic Science; Unist(Ulsan National Institute of Science and Technology) - Inventors: Ruoff Rodney S.; Sunghwan Jin - Web page: https://patentgrep.com/patent/US11993822B2 ## CPC - C21D 1/40: Direct resistance heating - C21D 9/46: for sheet metals - C22F 1/00: Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working (apparatus for mechanical working of metal B21, B23, B24) - C22F 1/002: {by rapid cooling or quenching; cooling agents used therefor} - C22F 1/14: of noble metals or alloys based thereon - C30B 1/02: by thermal treatment, e.g. strain annealing (C30B1/12 takes precedence) - C30B 1/04: Isothermal recrystallisation - C30B 29/02: Elements - C30B 35/00: Apparatus not otherwise provided for, specially adapted for the growth, production or after-treatment of single crystals or of a homogeneous polycrystalline material with defined structure - C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B) - C22F: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass, C23F17/00) - 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 ## Abstract The present invention relates to a method for manufacturing a monocrystalline metal foil and a monocrystalline metal foil manufactured thereby, the method comprising the steps of: fixing each of the ends of a polycrystalline metal foil to electrodes; and heat-treating the fixed polycrystalline metal foil to manufacture a monocrystalline metal foil. ## Claims ### Claim 1 A method for manufacturing a monocrystalline metal foil, the method comprising: a) a step of fixing each end of a polycrystalline metal foil by electrodes, respectively; and b) a step of heat treating the fixed polycrystalline metal foil to manufacture a monocrystalline metal foil, wherein the step a) further comprises a step of keeping the polycrystalline metal foil straight with a minimized stress applied to the polycrystalline metal foil by moving one or more electrodes which are fixing each end of the polycrystalline metal foil, respectively, before the step b) of heat treating the fixed polycrystalline metal foil, wherein the ends of the polycrystalline metal foil are opposite two edges of the polycrystalline metal foil, and a non-fixed portion, which is a region of the polycrystalline metal foil except for regions fixed by the electrodes is free of contact with solid materials, and wherein heat treating is performed while maintaining the polycrystalline metal foil in a straightened state by moving the one or more electrodes by a movement distance no greater than to an increased length of the polycrystalline metal foil due to thermal expansion. ### Claim 2 (depends on 1) The method of claim 1, wherein the heat treatment is performed by resistive heating. ### Claim 3 (depends on 1) The method of claim 1, wherein the step b) is performed by including: i) a primary heat treatment step of increasing a temperature of the polycrystalline metal foil by applying a current to the polycrystalline metal foil using the electrodes; and ii) a secondary heat treatment step of performing annealing at a finally increased temperature for a predetermined time. ### Claim 4 (depends on 3) The method of claim 3, wherein, in the primary heat treatment in the step i), the temperature is increased up to a temperature in the secondary heat treatment in the step ii). ### Claim 5 (depends on 4) The method of claim 4, wherein the temperature in the secondary heat treatment satisfies the following Relational Expression 2, 0.3×Tm≤T