A method for manufacturing a semiconductor device comprises dry-etching a thin film using a resist mask carrying patterns in which at least one of the width of each pattern and the space between neighboring two patterns ranges from 32 to 130 nm using a halogenated carbon-containing compound gas with the halogen being at least two members selected from the group consisting of F, I and Br. The ratio of at least one of I and Br is not more than 26% of the total amount of the halogen atoms as expressed in terms of the atomic compositional ratio to transfer the patterns onto the thin film. Such etching of a thin film avoids causing damage to the resist mask used. The resulting thin film carrying the transferred patterns is used as a mask for subjecting the underlying material to dry-etching.