# US 2020/0286756 A1 · Light irradiation type heat treatment method and heat treatment apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0286756 A1 - Document ID: US20200286756A1 - Status: Published application - Kind: A1 - Application number: 16/727,129 - Filed: 2019-12-26 - Published: 2020-09-10 - Earliest claimed: 2019-03-08 - Assignees: SCREEN Holdings Co., Ltd. - Applicants: SCREEN Holdings Co., Ltd. - Inventors: Akitsugu UEDA; Kazuhiko FUSE - Web page: https://patentgrep.com/patent/US20200286756A1 ## CPC - H10P 72/0436: {mainly by radiation} - H05B 3/0047: {for semiconductor manufacture} - H10P 14/6309: {of silicon in uncombined form, i.e. pure silicon} - H10P 14/69215: {the material being a silicon oxide, e.g. SiO2} - H10P 34/422: {using incoherent radiation} - H10P 95/90: Thermal treatments, e.g. annealing or sintering - H10P 14/6322: {Formation by thermal treatments (formation by plasma treatment H10P14/6319)} - H10P 72/3302: {Mechanical parts of transfer devices} - H10P 72/7624: {characterised by the mechanical construction of the susceptor, stage or support} - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract A silicon semiconductor wafer is transported into a chamber, and preheating of the semiconductor wafer is started in a nitrogen atmosphere by irradiation with light from halogen lamps. When the temperature of the semiconductor wafer reaches a predetermined switching temperature in the course of the preheating, oxygen gas is supplied into the chamber to change the atmosphere within the chamber from the nitrogen atmosphere to an oxygen atmosphere. Thereafter, a front surface of the semiconductor wafer is heated for an extremely short time period by flash irradiation. Oxidation is suppressed when the temperature of the semiconductor wafer is relatively low below the switching temperature, and is caused after the temperature of the semiconductor wafer becomes relatively high. As a result, a dense, thin oxide film having good properties with fewer defects at an interface with a silicon base layer is formed on the front surface of the semiconductor wafer. ## Claims ### Claim 1 A method of irradiating a substrate with light to heat the substrate, thereby forming an oxide film, said method comprising the steps of: (a) putting a substrate into a chamber; (b) irradiating said substrate with light to heat said substrate; and (c) supplying an oxidizing gas into said chamber to change an atmosphere within said chamber from an inert gas atmosphere to an oxidizing atmosphere when the temperature of said substrate reaches a predetermined switching temperature in the course of said step (b). ### Claim 2 (depends on 1) The method according to claim 1, wherein said step (b) includes the steps of: (b-1) irradiating said substrate with light from a continuous lighting lamp; and (b-2) irradiating said substrate with a flash of light from a flash lamp, said step (b-2) being performed after said step (b-1), wherein the supply of said oxidizing gas into said chamber starts in the course of said step (b-1). ### Claim 3 (depends on 2) The method according to claim 2, wherein said substrate is irradiated with said flash of light when the concentration of said oxidizing gas within said chamber reaches a predetermined value. ### Claim 4 (depends on 2) The method according to claim 2, wherein said substrate is irradiated with said flash of light, whereby an oxide film is formed on a surface of said substrate and impurities implanted in said substrate are activated. ### Claim 5 (depends on 1) The method according to claim 1, wherein the supply of said oxidizing gas into said chamber is stopped and pressure within said chamber is reduced after the completion of said step (b). ### Claim 6 (depends on 1) The method according to claim 1, wherein the supply of said oxidizing gas into said chamber is stopped and hydrogen gas is supplied into said chamber after the completion of said step (b). ### Claim 7 (depends on 1) The method according to claim 1, wherein the supply of said oxidizing gas into said chamber is stopped and argon gas or xenon gas is supplied into said chamber after the completion of said step (b). ### Claim 8 (depends on 1) The method according to claim 1, wherein said substrate is a silicon substrate, and said oxidizing gas is a gas selected from the group consisting of oxygen, ozone, oxygen radicals, and water vapor. ### Claim 9 (depends on 8) The method according to claim 8, wherein said oxidizing gas is mixed with an inert gas, and the gas mixture is supplied into said chamber in said step (c). ### Claim 10 (depends on 8) The method according to claim 8, wherein said switching temperature is 400° C. or above. ### Claim 11 A heat treatment apparatus for irradiating a substrate with light to heat the substrate, thereby forming an oxide film, said heat treatment apparatus comprising: a chamber for receiving a substrate therein; a light irradiator for irradiating said substrate with light to heat said substrate; a gas supply part for supplying an oxidizing gas into said chamber; and a controller for controlling said gas supply part so as to supply said oxidizing gas into said chamber to change an atmosphere within said chamber from an inert gas atmosphere to an oxidizing atmosphere when the temperature of said substrate reaches a predetermined switching temperature in the course of the process of heating said substrate by irradiating said substrate with light from said light irradiator. ### Claim 12 (depends on 11) The heat treatment apparatus according to claim 11, wherein: said light irradiator includes a continuous lighting lamp for irradiating said substrate with light to preheat said substrate, and a flash lamp for irradiating said substrate with a flash of light after said preheating; and said controller controls said gas supply part so as to start the supply of said oxidizing gas into said chamber in the course of said preheating. ### Claim 13 (depends on 12) The heat treatment apparatus according to claim 12, wherein said flash lamp irradiates said substrate with said flash of light when the concentration of said oxidizing gas within said chamber reaches a predetermined value. ### Claim 14 (depends on 12) The heat treatment apparatus according to claim 12, wherein said flash lamp irradiates said substrate with said flash of light, whereby an oxide film is formed on a surface of said substrate and impurities implanted in said substrate are activated. ### Claim 15 (depends on 11) The heat treatment apparatus according to claim 11, further comprising a pressure reduction part for reducing pressure within said chamber, wherein said gas supply part stops the supply of said oxidizing gas into said chamber and said pressure reduction part reduces the pressure within said chamber after the completion of the process of heating said substrate by irradiating said substrate with light from said light irradiator. ### Claim 16 (depends on 11) The heat treatment apparatus according to claim 11, wherein said gas supply part stops the supply of said oxidizing gas into said chamber and supplies hydrogen gas into said chamber after the completion of the process of heating said substrate by irradiating said substrate with light from said light irradiator. ### Claim 17 (depends on 11) The heat treatment apparatus according to claim 11, wherein said gas supply part stops the supply of said oxidizing gas into said chamber and supplies argon gas or xenon gas into said chamber after the completion of the process of heating said substrate by irradiating said substrate with light from said light irradiator. ### Claim 18 (depends on 11) The heat treatment apparatus according to claim 11, wherein said substrate is a silicon substrate, and said oxidizing gas is a gas selected from the group consisting of oxygen, ozone, oxygen radicals, and water vapor. ### Claim 19 (depends on 18) The heat treatment apparatus according to claim 18, wherein said gas supply part mixes said oxidizing gas with an inert gas to supply the gas mixture into said chamber. ### Claim 20 (depends on 18) The heat treatment apparatus according to claim 18, wherein said switching temperature is 400° C. or above.