A plurality of resist membranes are formed on a membrane of goods to be etched. The top resist is patterned by light beam, laser beam, X-rays, or electron beams. The wafer is transferred to a first unit into which discharging gas is introduced and plasma is generated in order to dry-etch the multilayer resists. The multilayer is transferred to a second unit in vacuum environment. In the second unit, the membrane of the wafer is dry-etched in a predetermined depth. The wafer then is transferred to a third unit in vacuum atmosphere so as to remove part of the resist depending a mask pattern and treat the resist by plasma.