Method for manufacturing semiconductor device and semiconductor device

1. A method for manufacturing a semiconductor device, comprising:

forming, on a substrate, an element isolation insulating film which includes a protruding portion protruding above a level of a surface of the substrate;

forming a first film on the substrate and on the element isolation insulating film;

polishing the first film to expose the protruding portion;

forming a first resist pattern which straddles the first film and the protruding portion after polishing the first film;

patterning the first film using the first resist pattern as a mask to form a first pattern; and

forming a sidewall film at side surfaces of the first pattern.

2. The method for manufacturing the semiconductor device according to claim 1 , comprising:

forming a second resist pattern on the substrate after forming the sidewall film;

implanting impurities into the substrate using the first pattern, the sidewall film, and the second resist pattern as a mask; and

removing the second resist pattern by chemical solution treatment.

3. The method for manufacturing the semiconductor device according to claim 2 , comprising:

forming a metal film on the substrate after removing the second resist pattern;

performing heat treatment to form a silicide in the substrate; and

removing the unreacted metal film on the substrate by chemical solution treatment.

4. The method for manufacturing the semiconductor device according to claim 3 , comprising

cleaning the substrate before forming the metal film on the substrate.

5. The method for manufacturing the semiconductor device according to claim 2 , comprising:

forming a first insulating film on the substrate after implanting the impurities;

polishing the first insulating film to expose the first pattern;

removing the first pattern after polishing the first insulating film;

forming a metal film on the first insulating film after removing the first pattern; and

polishing the metal film to expose the first insulating film.

6. The method for manufacturing the semiconductor device according to claim 1 , wherein

the forming the element isolation insulating film including the protruding portion comprises:

forming a trench in the substrate;

forming a second insulating film in the trench;

polishing the second insulating film;

forming a third resist pattern on the second insulating film after polishing the second insulating film; and

etching the second insulating film using the third resist pattern as a mask to make an upper surface of the second insulating film in a region not covered with the third resist pattern lower than the surface of the substrate.