PURPOSE: To form a pattern having a sawtooth-shaped cross section by irradiating collimated far ultraviolet beams in the direction that the parallel plane of a semiconductor substrate crosses at right angles with the side surface of the pattern and from an oblique upper section and sensitizing and developing the section of a far ultraviolet beam resist not shielded by light.

CONSTITUTION: A novolak group positive type photo-resist 2 is applied onto an Si substrate l, and pre-baked. The repetitive patterns of lines and spaces are drawn through electron-beam exposure, and developed by an alkali group developer, thus forming a pattern. A resist for far ultraviolet beam exposure is applied, a cylindrical type plasma etching device is used, PMMA is removed through plasma ashing, and collimated far ultraviolet beams are irradiated in the direction that the parallel plane of the substrate 1 crosses at right angles with the side surfaces of the repetitive patterns and from an oblique upper section. Far ultraviolet beams are shielded by the resist 2, only sections not exposed are left, pattern sections are removed through development, and only oblique patterns are shaped. Accordingly, A resist pattern with a sawtooth- shaped cross section can he formed.