to a method in which a fine pattern is formed over semiconductor substrate 1 with tin film 2 on its surface as shown in fig1 a tin film 2 is formed on semiconductor substrate 1 in tin film 2 a great many lone pairs of electrons of nitrogen atoms are present and the surface concentration of ammonia is high therefore the surface of tin film 2 is basic in other words a base 3 is present in the surface of tin film 2 acid solution 7 i e 20 percent by weight of a dichloroacetic acid solution is prepared by dissolving dichloroacetic acid in ethyl lactate as shown in fig1 b acid solution 7 thus prepared is drip fed onto semiconductor substrate 1 so that the entire surface of semiconductor substrate 1 is dipped into acid solution 7 for 20 seconds thereafter acid solution 7 is spin dried and the base 3 present in tin film 39 s 2 surfac is neutralized by an acid 8 present in acid solution 7 as a result tin film 2 with its surface neutralized is obtained next as shown in fig1 c a two component chemically amplified resist 4 of positive type e g wkr pt 2 manufactured by wako pure chemical industries ltd is spin applied onto tin film 2 then a prebaking process is carried out for 90 seconds at a temperature of 90 u00b0 c to form resist film 4 next.