Semiconductor device fabricating method, plasma processing system and storage medium

A plasma processing method comprising

• providing a substrate having thereon a SiC film, a SiCOH film, an organic film, a first SiO2 film, a SiN film, a second SiO2 film, an antireflection film and a patterned resist film which are stacked in layers, wherein the patterned resist film has an opening having a first opening size, and wherein a total thickness of the antireflection film and the resist film is greater than a total thickness of the first SiO2 film, the SiN film and the second SiO2 film;
• placing the provided substrate into a processing chamber;
• supplying a first processing gas into the processing chamber and generating a plasma of the first processing gas, thereby depositing a polymer on surfaces of the resist film including interior surfaces of the opening of the resist film, and thereby narrowing the opening of the resist film from the first opening size to a second opening size;
• supplying a second processing gas into the processing chamber and generating a plasma of the second processing gas, thereby performing non-selective etching of the resist film, the antireflection film, the second SiO2 film, the SiN film and the first SiO2 film down to the organic film, by using the resist film having the opening having the second opening size as an etch mask, thereby forming a part of a via hole;
• supplying a third processing gas into the processing chamber and generating a plasma of the third processing gas, thereby ashing the antireflection film remaining on the second SiO2 film and the SiN film, and etching the organic film by using the SiN film as an etch mask;
• supplying a fourth processing gas into the processing chamber and generating a plasma of the fourth processing gas, thereby etching the SiN film by using the second SiO2 film as an etch mask:
• supplying a fifth processing gas into the processing chamber and generating a plasma of the fifth processing gas, thereby etching the first SiO2 film and the SiCOH film by using the SiN film as an etch mask;
• and
• etching the SiN film, the SiC film and the organic film, thereby completing formation of the via hole and a trench,
• wherein the second processing gas is a mixed gas comprising CF4 gas, CHF3 gas and O2 gas.