# US 10,319,613 B2 · Method of selectively etching first region made of silicon nitride against second region made of silicon oxide > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,319,613 B2 - Document ID: US10319613B2 - Status: Granted - Kind: B2 - Application number: 15/837,195 - Filed: 2017-12-11 - Published: 2018-06-14 - Granted: 2019-06-11 - Earliest claimed: 2016-12-13 - Assignees: Tokyo Electron Limited - Applicants: Tokyo Electron Limited - Inventors: Masahiro Tabata; Sho Kumakura - Web page: https://patentgrep.com/patent/US10319613B2 ## CPC - H10P 72/0421: {for drying etching} - H01J 37/00: Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof (H01J33/00, H01J40/00, H01J41/00, H01J47/00, H01J49/00 take precedence) - H01J 37/32137: {controlling of the discharge by modulation of energy} - H01J 37/32174: {Circuits specially adapted for controlling the RF discharge} - H10P 50/283: {by chemical means} - H10P 72/00: Handling or holding of wafers, substrates or devices during manufacture or treatment thereof - H01J 37/32449: {Gas control, e.g. control of the gas flow} - H01J 2237/334: Etching - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract Generation of a deposit can be suppressed and high selectivity can be acquired when etching a first region made of silicon nitride selectively against a second region made of silicon oxide. A method includes preparing a processing target object having the first region and the second region within a chamber provided in a chamber main body of a plasma processing apparatus; generating plasma of a first gas including a gas containing hydrogen within the chamber to form a modified region by modifying a part of the first region with active species of the hydrogen; and generating plasma of a second gas including a gas containing fluorine within the chamber to remove the modified region with active species of the fluorine. ## Claims ### Claim 1 A method of etching a first region made of silicon nitride selectively against a second region made of silicon oxide, comprising: preparing a processing target object having the first region and the second region within a chamber provided in a chamber main body of a plasma processing apparatus; generating plasma of a first gas including a gas containing hydrogen within the chamber to form a modified region by modifying a part of the first region with active species of the hydrogen; and generating plasma of a second gas including a gas containing fluorine within the chamber to remove the modified region with active species of the fluorine, wherein the processing target object further has a third region made of silicon, and the first gas further includes a gas containing oxygen. ### Claim 2 (depends on 1) The method of claim 1, wherein the first region is provided to cover the second region and the third region. ### Claim 3 (depends on 1) The method of claim 1, wherein a flow rate ratio of the gas containing oxygen in the first gas to the gas containing hydrogen in the first gas is set to be in a range from 3/100 to 9/100. ### Claim 4 (depends on 1) The method of claim 1, wherein the gas containing oxygen is an O2 gas. ### Claim 5 (depends on 1) The method of claim 1, wherein the second gas further contains oxygen. ### Claim 6 (depends on 1) The method of claim 1, wherein the second gas further contains hydrogen. ### Claim 7 (depends on 1) The method of claim 1, wherein in the generating of the plasma of the first gas, a bias power is supplied to a stage configured to hold the processing target object mounted thereon, and a high frequency power is supplied to an inductively coupled plasma antenna. ### Claim 8 (depends on 1) The method of claim 1, wherein in the generating of the plasma of the second gas, a high frequency power is supplied to an inductively coupled plasma antenna. ### Claim 9 (depends on 1) The method of claim 1, wherein in the generating of the plasma of the first gas, a bias power is supplied to a stage which is configured to hold the processing target object mounted thereon. ### Claim 10 (depends on 9) The method of claim 9, wherein in the generating of the plasma of the second gas, a high frequency power is supplied to an inductively coupled plasma antenna. ### Claim 11 A method of etching a first region made of silicon nitride selectively against a second region made of silicon oxide, comprising: preparing a processing target object having the first region and the second region within a chamber provided in a chamber main body of a plasma processing apparatus; generating plasma of a first gas including a gas containing hydrogen within the chamber to form a modified region by modifying a part of the first region with active species of the hydrogen; and generating plasma of a second gas including a gas containing fluorine within the chamber to remove the modified region with active species of the fluorine, wherein a plurality of sequences each of which includes the generating of the plasma of the first gas and the generating of the plasma of the second gas are performed in sequence, the processing target object further has a third region made of silicon, the first region is provided to cover the second region and the third region before the plurality of sequences are performed, the plurality of sequences include one or more first sequences performed until a time immediately before the third region is exposed or until the third region is exposed; and one or more second sequences performed to oxidize a surface of the third region after the one or more first sequences, and the first gas further includes a gas containing oxygen in at least one second sequence. ### Claim 12 (depends on 11) The method of claim 11, wherein the first gas does not contain the gas containing oxygen in the one or more first sequences. ### Claim 13 (depends on 11) The method of claim 11, wherein the plurality of sequences further include one or more third sequences performed after the one or more second sequences, and the first gas does not include the gas containing oxygen in the one or more third sequences.