Cleaning gases and etching gases

A method comprising etching a silicon-containing film with a gas, which gas comprises FCOF and O2, wherein the mixing molar ratio of FCOF to O2 (FCOF/O2) satisfies the formula 1≦FCOF/O2≦9, and optionally other gases, wherein the total content of FCOF and O2 is in the range of 70 to 100 mol % based on the total gas amount being 100 mol %.

A gas comprising CF3OCOF and O2, and optionally other gases.

A method comprising etching a silicon-containing film with a gas, which gas comprises CF3OCOF and O2, and optionally other gases.

A gas comprising CF3OCF2OCOF and O2, and optionally other gases.

A method comprising etching a silicon-containing film with a gas, which gas comprises CF3OCF2OCOF and O2, and optionally other gases.

A gas comprising at least one fluorine compound selected from the group consisting of FCOF, CF3OCOF and CF3OCF2OCOF, and O2, wherein the mixing molar ratio of the at least one fluorine compound to O2 (F compound/O2) satisfies the formula 1≦F compound/O2≦9, and optionally other gases, wherein the total content of the at least one fluorine compound and O2 is in the range of 70 to 100 mol % based on the total gas amount being 100 mol %.

A method comprising etching a silicon-containing film with a gas, which gas comprises at least one fluorine compound selected from the group consisting of FCOF, CF3OCOF and CF3OCF2OCOF, and O2, wherein the mixing molar ratio of the at least one fluorine compound to O2 (F compound/O2) satisfies the formula 1≦F compound/O2≦9, and optionally other gases, wherein the total content of the at least one fluorine compound and O2 is in the range of 70 to 100 mol % based on the total gas amount being 100 mol %.

A gas comprising CF2(COF)2 and O2, and optionally other gases, wherein the total content of CF2(COF)2 and O2 is in the range of 70 to 100 mol % based on the total gas amount being 100 mol %.

A method comprising etching a silicon-containing film with a gas, which gas comprises CF2(COF)2 and O2, and optionally other gases, wherein the total content of CF2(COF)2 and O2 is in the range of 70 to 100 mol % based on the total gas amount being 100 mol %.