# US 7,608,527 B2 · Laser irradiation method and method for manufacturing crystalline semiconductor film > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,608,527 B2 - Document ID: US7608527B2 - Status: Granted - Kind: B2 - Application number: 11/017,900 - Filed: 2004-12-22 - Published: 2005-06-30 - Granted: 2009-10-27 - Earliest claimed: 2003-12-26 - Assignees: Semiconductor Energy Laboratory Co., Ltd. - Inventors: Koichiro Tanaka; Yoshiaki Yamamoto - Web page: https://patentgrep.com/patent/US7608527B2 ## CPC - B23K 26/0622: by shaping pulses - B23K 26/0732: {into a rectangular shape} - B23K 26/0736: {into an oval shape, e.g. elliptic shape} - C30B 1/00: Single-crystal growth directly from the solid state (unidirectional demixing of eutectoid materials C30B3/00; under a protective fluid C30B27/00) - C30B 13/24: using electromagnetic waves - C30B 29/06: Silicon - H10D 30/0314: {of lateral top-gate TFTs comprising only a single gate} - H10D 30/0321: {comprising silicon, e.g. amorphous silicon or polysilicon} - H10D 86/0229: {characterised by control of the annealing or irradiation parameters} - H10P 14/2922: {being non-crystalline insulating materials, e.g. glass or polymers} - H10P 14/3238: {being insulating materials} - H10P 14/3248: {consisting of two layers} - H10P 14/3411: {Silicon, silicon germanium or germanium} - H10P 14/3456: {Polycrystalline} - H10P 14/381: {Beam shaping, e.g. using a mask} - H10P 14/3816: {Pulsed laser beam} - H10P 14/382: {Scanning of a beam} - 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 - 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 - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract Even when the laser irradiation is performed under the same condition with the energy distribution of the beam spot shaped as appropriate, the energy given to the irradiated surface is not yet homogeneous. When a semiconductor film is crystallized to form a crystalline semiconductor film using such inhomogeneous irradiation energy, the crystallinity becomes inhomogeneous in this film, and the characteristic of semiconductor elements manufactured using this film varies. In the present invention, an irradiated object formed over a substrate is irradiated with a laser beam having the pulse width that is an order of picosecond (10−12 second) or less. ## Claims ### Claim 1 A method for manufacturing a semiconductor device comprising: forming an amorphous semiconductor film over a substrate having a refractive index n and a thickness d; and forming a crystal grain grown continuously in a scanning direction by irradiating the amorphous semiconductor film with a laser beam emitted from a pulsed laser oscillator while scanning the substrate in the scanning direction, wherein the laser beam has a pulse width t that satisfies an inequality ct<2nd where c is a speed of light in vacuum. ### Claim 2 (depends on 1) The method according to claim 1, wherein the laser beam emitted from the pulsed laser oscillator is converted into a second harmonic by a non-linear optical element. ### Claim 3 (depends on 1) The method according to claim 1, wherein the amorphous semiconductor film comprises silicon film. ### Claim 4 (depends on 1) The method according to claim 1, wherein the laser beam is incident vertically into the amorphous semiconductor film. ### Claim 5 (depends on 1) The method according to claim 1, wherein the laser beam is incident obliquely into the amorphous semiconductor film. ### Claim 6 (depends on 1) The method according to claim 1, wherein the semiconductor device is incorporated in to an electronic device selected from the group consisting of a personal computer, a video camera, a mobile computer, a goggle type display, a player, a digital camera, a cellular phone, mobile book, and a display. ### Claim 7 (depends on 1) The method according to claim 1, wherein the laser beam has a repetition rate of 10 MHz or more. ### Claim 8 A method for manufacturing a semiconductor device comprising: forming an amorphous semiconductor film over a substrate having a refractive index n and a thickness d; and forming a crystal grain grown continuously in a scanning direction by irradiating the amorphous semiconductor film with a laser beam emitted from a pulsed laser oscillator while scanning the substrate in the scanning direction, wherein the laser beam has a pulse width t that satisfies an inequality ct<4nd where c is a speed of light in vacuum. ### Claim 9 (depends on 8) The method according to claim 8, wherein the laser beam emitted from the pulsed laser oscillator is converted into a second harmonic by a non-linear optical element. ### Claim 10 (depends on 8) The method according to claim 8, wherein the amorphous semiconductor film comprises silicon film. ### Claim 11 (depends on 8) The method according to claim 8, wherein the laser beam is incident vertically into the amorphous semiconductor film. ### Claim 12 (depends on 8) The method according to claim 8, wherein the laser beam is incident obliquely into the amorphous semiconductor film. ### Claim 13 (depends on 8) The method according to claim 8, wherein the semiconductor device is incorporated in to an electronic device selected from the group consisting of a personal computer, a video camera, a mobile computer, a goggle type display, a player, a digital camera, a cellular phone, mobile book, and a display. ### Claim 14 (depends on 8) The method according to claim 8, wherein the laser beam has a repetition rate of 10 MHz or more. ### Claim 15 A method for manufacturing a semiconductor device comprising: forming an amorphous semiconductor film over a substrate having a refractive index n and a thickness d; and forming a crystal grain grown continuously in a scanning direction by irradiating the amorphous semiconductor film with a laser beam emitted from a pulsed laser oscillator while scanning the substrate in the scanning direction, wherein one point in the amorphous semiconductor film is irradiated simultaneously with both the laser beam being incident thereinto and the laser beam reflected on a rear surface of the substrate for a time corresponding to 10% or less of a pulse width of the laser beam. ### Claim 16 (depends on 15) The method according to claim 15, wherein the laser beam emitted from the pulsed laser oscillator is converted into a second harmonic by a non-linear optical element. ### Claim 17 (depends on 15) The method according to claim 15, wherein the amorphous semiconductor film comprises silicon film. ### Claim 18 (depends on 15) The method according to claim 15, wherein the laser beam is incident vertically into the amorphous semiconductor film. ### Claim 19 (depends on 15) The method according to claim 15, wherein the laser beam is incident obliquely into the amorphous semiconductor film. ### Claim 20 (depends on 15) The method according to claim 15, wherein the semiconductor device is incorporated in to an electronic device selected from the group consisting of a personal computer, a video camera, a mobile computer, a goggle type display, a player, a digital camera, a cellular phone, mobile book, and a display. ### Claim 21 (depends on 15) The method according to claim 15, wherein the laser beam has a repetition rate of 10 MHz or more. ### Claim 22 A method for manufacturing a semiconductor device comprising: forming a crystal grain grown continuously in a scanning direction by irradiating a crystalline semiconductor film formed over a substrate having a refractive index n and a thickness d with a laser beam emitted from a pulsed laser oscillator while scanning the substrate in the scanning direction so as to improve crystallinity of the crystalline semiconductor film, wherein the laser beam has a pulse width t that satisfies an inequality ct<2nd where c is a speed of light in vacuum. ### Claim 23 (depends on 22) The method according to claim 22, wherein the laser beam emitted from the pulsed laser oscillator is converted into a second harmonic by a non-linear optical element. ### Claim 24 (depends on 22) The method according to claim 22, wherein the crystalline semiconductor film comprises silicon film. ### Claim 25 (depends on 22) The method according to claim 22, wherein the laser beam is incident vertically into the crystalline semiconductor film. ### Claim 26 (depends on 22) The method according to claim 22, wherein the laser beam is incident obliquely into the crystalline semiconductor film. ### Claim 27 (depends on 22) The method according to claim 22, wherein the semiconductor device is incorporated in to an electronic device selected from the group consisting of a personal computer, a video camera, a mobile computer, a goggle type display, a player, a digital camera, a cellular phone, mobile book, and a display. ### Claim 28 (depends on 22) The method according to claim 22, wherein the laser beam has a repetition rate of 10 MHz or more. ### Claim 29 A method for manufacturing a semiconductor device comprising: forming a crystal grain grown continuously in a scanning direction by irradiating a crystalline semiconductor film formed over a substrate having a refractive index n and a thickness d with a laser beam emitted from a pulsed laser oscillator while scanning the substrate in the scanning direction so as to improve crystallinity of the crystalline semiconductor film, wherein the laser beam has a pulse width t that satisfies an inequality ct<4nd where c is a speed of light in vacuum. ### Claim 30 (depends on 29) The method according to claim 29, wherein the laser beam emitted from the pulsed laser oscillator is converted into a second harmonic by a non-linear optical element. ### Claim 31 (depends on 29) The method according to claim 29, wherein the crystalline semiconductor film comprises silicon film. ### Claim 32 (depends on 29) The method according to claim 29, wherein the laser beam is incident vertically into the crystalline semiconductor film. ### Claim 33 (depends on 29) The method according to claim 29, wherein the laser beam is incident obliquely into the crystalline semiconductor film. ### Claim 34 (depends on 29) The method according to claim 29, wherein the semiconductor device is incorporated in to an electronic device selected from the group consisting of a personal computer, a video camera, a mobile computer, a goggle type display, a player, a digital camera, a cellular phone, mobile book, and a display. ### Claim 35 (depends on 29) The method according to claim 29, wherein the laser beam has a repetition rate of 10 MHz or more. ### Claim 36 A method for manufacturing a semiconductor device comprising: forming a crystal grain grown continuously in a scanning direction by irradiating a crystalline semiconductor film formed over a substrate having a refractive index n and a thickness d with a laser beam emitted from a pulsed laser oscillator while scanning the substrate in the scanning direction so as to improve crystallinity of the crystalline semiconductor film, wherein one point in the crystalline semiconductor film is irradiated simultaneously with both the laser beam being incident thereinto and the laser beam reflected on a rear surface of the substrate for a time corresponding to 10% or less of a pulse width of the laser beam. ### Claim 37 (depends on 36) The method according to claim 36, wherein the laser beam emitted from the pulsed laser oscillator is converted into a second harmonic by a non-linear optical element. ### Claim 38 (depends on 36) The method according to claim 36, wherein the crystalline semiconductor film comprises silicon film. ### Claim 39 (depends on 36) The method according to claim 36, wherein the laser beam is incident vertically into the crystalline semiconductor film. ### Claim 40 (depends on 36) The method according to claim 36, wherein the laser beam is incident obliquely into the crystalline semiconductor film. ### Claim 41 (depends on 36) The method according to claim 36, wherein the semiconductor device is incorporated in to an electronic device selected from the group consisting of a personal computer, a video camera, a mobile computer, a goggle type display, a player, a digital camera, a cellular phone, mobile book, and a display. ### Claim 42 (depends on 36) The method according to claim 36, wherein the laser beam has a repetition rate of 10 MHz or more.