# US 2022/0285166 A1 · Substrate processing method and substrate processing apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0285166 A1 - Document ID: US20220285166A1 - Status: Published application - Kind: A1 - Application number: 17/652,320 - Filed: 2022-02-24 - Published: 2022-09-08 - Earliest claimed: 2021-03-02 - Assignees: Tokyo Electron Limited - Applicants: Tokyo Electron Limited - Inventors: Takumi Honda - Web page: https://patentgrep.com/patent/US20220285166A1 ## CPC - H10P 50/283: {by chemical means} - C09K 13/04: containing an inorganic acid - H10P 14/662: {Laminate layers, e.g. stacks of alternating high-k metal oxides (adhesion layers or buffer layers H10P14/6508, H10P14/6548)} - H10P 14/69215: {the material being a silicon oxide, e.g. SiO2} - H10P 14/69433: {the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz} - H10P 50/642: {Chemical etching} - H10P 72/0422: {for wet etching} - H10P 72/0426: {with the semiconductor substrates being dipped in baths or vessels} - H10P 72/0456: {in-line arrangement} - H10P 72/0604: {Process monitoring, e.g. flow or thickness monitoring} - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE ## Abstract A substrate processing method includes preparing a phosphoric acid processing liquid, etching a substrate and increasing a concentration of the precipitation inhibitor. The phosphoric acid processing liquid is prepared by supplying a precipitation inhibitor into a phosphoric acid aqueous solution. The substrate having a silicon oxide film and a silicon nitride film is etched by immersing the substrate in a processing tub. The concentration of the precipitation inhibitor is increased by additionally supplying the precipitation inhibitor into the phosphoric acid processing liquid when a number of substrates etched has reached a first threshold value or when a silicon concentration in the phosphoric acid processing liquid has reached a second threshold value. The etching of the substrate comprises etching a new substrate by immersing the new substrate in the processing tub in which the phosphoric acid processing liquid with the increased concentration of the precipitation inhibitor is stored. ## Claims ### Claim 1 A substrate processing method, comprising: preparing a phosphoric acid processing liquid by supplying a precipitation inhibitor configured to inhibit precipitation of silicon oxide into a phosphoric acid aqueous solution; etching a substrate having a silicon oxide film and a silicon nitride film by immersing the substrate in a processing tub in which the phosphoric acid processing liquid is stored; and increasing a concentration of the precipitation inhibitor in the phosphoric acid processing liquid by additionally supplying the precipitation inhibitor into the phosphoric acid processing liquid in the processing tub when a number of substrates etched by the phosphoric acid processing liquid has reached a first threshold value or when a silicon concentration in the phosphoric acid processing liquid has reached a second threshold value, wherein the etching of the substrate comprises, after the increasing of the concentration of the precipitation inhibitor, etching a new substrate by immersing the new substrate in the processing tub in which the phosphoric acid processing liquid with the increased concentration of the precipitation inhibitor is stored. ### Claim 2 (depends on 1) The substrate processing method of claim 1, further comprising: draining all of the phosphoric acid processing liquid from the processing tub when the number of the substrates etched by the phosphoric acid processing liquid has reached a third threshold value higher than the first threshold value, or when the silicon concentration in the phosphoric acid processing liquid has reached a fourth threshold value higher than the second threshold value. ### Claim 3 (depends on 2) The substrate processing method of claim 2, wherein the increasing of the concentration of the precipitation inhibitor is performed twice or more between an end of the preparing of the phosphoric acid processing liquid and a start of the draining of all of the phosphoric acid processing liquid. ### Claim 4 (depends on 3) The substrate processing method of claim 3, wherein the increasing of the concentration of the precipitation inhibitor comprises: additionally supplying the precipitation inhibitor into the phosphoric acid processing liquid within the processing tub; and circulating the precipitation inhibitor together with the phosphoric acid processing liquid through a circulation path provided in the processing tub. ### Claim 5 (depends on 2) The substrate processing method of claim 2, wherein the increasing of the concentration of the precipitation inhibitor comprises: additionally supplying the precipitation inhibitor into the phosphoric acid processing liquid within the processing tub; and circulating the precipitation inhibitor together with the phosphoric acid processing liquid through a circulation path provided in the processing tub. ### Claim 6 (depends on 5) The substrate processing method of claim 5, wherein the processing tub comprises: an inner tub, having a top opening, configured to store the phosphoric acid processing liquid therein; and an outer tub disposed outside the inner tub to receive the phosphoric acid processing liquid flown out from the opening, wherein the inner tub is provided with a gas discharge unit configured to discharge a gas into the inner tub, and in the additionally supplying of the precipitation inhibitor, the precipitation inhibitor is supplied into the inner tub. ### Claim 7 (depends on 6) The substrate processing method of claim 6, wherein in the additionally supplying of the precipitation inhibitor, the precipitation inhibitor is dripped onto a liquid surface of the phosphoric acid processing liquid from a position higher than the liquid surface within the inner tub. ### Claim 8 (depends on 2) The substrate processing method of claim 2, wherein the increasing of the concentration of the precipitation inhibitor is performed between an end of the etching of the substrate being currently performed and a start of the etching of the substrate to be performed next. ### Claim 9 (depends on 3) The substrate processing method of claim 3, wherein the increasing of the concentration of the precipitation inhibitor is performed between an end of the etching of the substrate being currently performed and a start of the etching of the substrate to be performed next. ### Claim 10 (depends on 1) The substrate processing method of claim 1, wherein the increasing of the concentration of the precipitation inhibitor comprises: additionally supplying the precipitation inhibitor into the phosphoric acid processing liquid within the processing tub; and circulating the precipitation inhibitor together with the phosphoric acid processing liquid through a circulation path provided in the processing tub. ### Claim 11 (depends on 10) The substrate processing method of claim 10, wherein the processing tub comprises: an inner tub, having a top opening, configured to store the phosphoric acid processing liquid therein; and an outer tub disposed outside the inner tub to receive the phosphoric acid processing liquid flown out from the opening, wherein the inner tub is provided with a gas discharge unit configured to discharge a gas into the inner tub, and in the additionally supplying of the precipitation inhibitor, the precipitation inhibitor is supplied into the inner tub. ### Claim 12 (depends on 11) The substrate processing method of claim 11, wherein in the additionally supplying of the precipitation inhibitor, the precipitation inhibitor is dripped onto a liquid surface of the phosphoric acid processing liquid from a position higher than the liquid surface within the inner tub. ### Claim 13 (depends on 1) The substrate processing method of claim 1, wherein the increasing of the concentration of the precipitation inhibitor is performed between an end of the etching of the substrate being currently performed and a start of the etching of the substrate to be performed next. ### Claim 14 A substrate processing apparatus, comprising: a processing tub; a preparing unit configured to prepare a phosphoric acid processing liquid by supplying a precipitation inhibitor configured to inhibit precipitation of silicon oxide into a phosphoric acid aqueous solution; a supplying unit configured to supply the precipitation inhibitor into the processing tub; and a controller configured to perform preparing the phosphoric acid processing liquid by controlling the preparing unit, etching a substrate having a silicon oxide film and a silicon nitride film by immersing the substrate in the processing tub in which the phosphoric acid processing liquid is stored, and increasing a concentration of the precipitation inhibitor in the phosphoric acid processing liquid by controlling the supplying unit to additionally supply the precipitation inhibitor into the phosphoric acid processing liquid in the processing tub when a number of substrates etched by the phosphoric acid processing liquid has reached a first threshold value or when a silicon concentration in the phosphoric acid processing liquid has reached a second threshold value, wherein the etching of the substrate comprises, after the increasing of the concentration of the precipitation inhibitor is performed, etching a new substrate by immersing the new substrate in the processing tub in which the phosphoric acid processing liquid with the increased concentration of the precipitation inhibitor is stored.