A method of forming a minute pattern with controlled resist profile by using chemically amplifying type resist and deep UV ray is disclosed. A positive chemically amplifying type resist is applied on a silicon substrate, to form a resist film of the resist on the silicon substrate. The resist film is selectively irradiated with KrF excimer laser beam by using a photomask. Thereafter, an electric field directed vertically downward is applied to the resist film while the resist film is heated. According to this method, H.sup.+ ions which are catalyst for destroying the dissolution inhibiting capability of the dissolution inhibitor generated in the resist film move vertically downward, so that diffusion of the H.sup.+ ions in the lateral direction during heating can be prevented. Consequently, a positive minute pattern having sidewall formed vertical to the substrate can be provided.