PURPOSE: To obtain a pattern superior in resolution, resistance to chemicals, adhesion, etc., and suitable for manufacture of IC, LSI, etc., by using a developing solvent mixture of n-heptane and n-butyl acetate in a specified volume ratio for developing a negative type cyclized rubber photoresist.

CONSTITUTION: A silicon wafer having a heat oxidized film is spin coated with a negative type cyclized butadiene rubber photoresist "OMR-83" made by TOKYO OKA CO., and prebaked to form a photoresist layer. This is exposed to far UV light through a mask and developed with a 9:1W2:3 by vol. mixture of n-heptane and n-butyl acetate. n-Heptane may be replaced by xylene up to 20vol%. As a result, swelling of the exposed parts is inhibited and the unexposed parts are prevented from remaining due to deficient dissolving, and fine patterns can be formed with high precision.