METHOD FOR ETHCING SILICON

摘要

[PROBLEMS] To improve the etching rate of silicon. [MEANS FOR SOLVING PROBLEMS] Water in an amount necessary for bringing the dew point of a mixed gas composed of CF4 as a fluorine material and Ar to 10°C to 40°C is added to the mixed gas, and the mixture is plasmatized at the atmospheric pressure. The plasmatized gas is mixed with an ozone-containing gas from an ozonizer (13) to prepare a reaction gas. The reaction gas contains not less than 1% by volume of ozone, a non-radical fluorine-type intermediate such as COF2, and not less than 0.4% by volume of a non-radical fluorine-type reactant such as HF. The ratio between the number of fluorine atoms (F) and the number of hydrogen atoms (H) is (F)/(H) > 1.8. This reaction gas is sprayed against a silicon film (91) (object material) having a temperature of 10°C to 50°C.