Method for removing silicon oxide film and processing apparatus

A method of removing silicon dioxide films from a surface of a workpiece having a natural oxide film thereon, said method comprising:

• removing the natural oxide film from the surface of the workpiece by a chemical process;
• forming a chemical oxide film on the surface as a protective film after removal of the natural oxide film, the chemical oxide film being a silicon dioxide film formed by a chemical process using a solution prepared by mixing H2O2 and NH4OH;
• and
• removing the chemical oxide film from the surface of the workpiece, under conditions that:
• a mixed gas containing HF gas and NH3 gas is used;
• a processing temperature for achieving etch selectivity for the chemical oxide film to a silicon nitride film is in the range of 200° C. to 600° C.;
• a processing pressure at which the workpiece is processed is not more than 53,200 Pa (400 Torr);
• and
• the flow rate ratio of HF gas to NH3 gas is in the range of 10:1 to 1:50.

A method of removing silicon dioxide films from a surface of a workpiece having a natural oxide film thereon, said method comprising:

• removing the natural oxide film from the surface of the workpiece by a chemical process;
• forming a chemical oxide film on the surface as a protective film after removal of the natural oxide film, the chemical oxide film being a silicon dioxide film formed by a chemical process using a solution prepared by mixing H2O2 and NH4OH;
• and
• removing the chemical oxide film from the surface of the workpiece under conditions that:
• a mixed gas containing HF gas and NH3 gas is used;
• a processing temperature for achieving etch selectivity for the chemical oxide film to a silicon dioxide film, which has been formed by CVD (Chemical Vapor Deposition), is in the range of 200° C. to 400° C.;
• a processing pressure at which the workpiece is processed is not more than 53,200 Pa (400 Torr);
• and
• the flow rate ratio of HF gas to NH3 gas is in the range of 10:1 to 1:50.

A method of removing silicon dioxide films from a surface of a workpiece having a natural oxide film thereon, said method comprising:

• removing the natural oxide film from the surface of the workpiece by a chemical process;
• forming a chemical oxide film on the surface as a protective film after removal of the natural oxide film, the chemical oxide film being a silicon dioxide film formed by a chemical process using a solution prepared by mixing H2O2 and NH4OH;
• and
• removing the chemical oxide film from the surface of the workpiece, under conditions that:
• a mixed gas containing HF gas and NH3 gas is used;
• a processing temperature for achieving etch selectivity for the chemical oxide film to a thermal oxide film is in the range of 100° C. to 600° C.;
• a processing pressure at which the workpiece is processed is not more than 53,200 Pa (400 Torr);
• and
• the flow rate ratio of HF gas to NH3 gas is in the range of 10:1 to 1:50.