Patent attributes
An etching method performed by an etching apparatus includes a first process of causing a first high-frequency power supply to output a first high-frequency power with a first frequency and causing a second high-frequency power supply to output a second high-frequency power with a second frequency lower than the first frequency in a cryogenic environment where the temperature of a wafer is −35° C. or lower, to generate plasma from a hydrogen-containing gas and a fluorine-containing gas and to etch, with the plasma, a multi-layer film of silicon dioxide and silicon nitride and a single-layer film of silicon dioxide that are formed on the wafer; and a second process of stopping the output of the second high-frequency power supply. The first process and the second process are repeated multiple times, and the first process is shorter in time than the second process.
