Semiconductor device and producing method thereof

1. A semiconductor device manufacturing method comprising:

forming a fin region over a substrate, the fin region having an apex portion and a sidewall portion and extending in a first direction;

forming a dummy gate electrode over the fin region, the dummy gate electrode extending in a second direction different from the first direction;

forming a first insulating film over the dummy gate electrode and the fin region;

polishing the first insulating film until the dummy gate electrode is exposed;

removing at least part of the exposed dummy gate electrode to form a trench, a surface of the fin region being exposed in the trench while leaving at least part of the dummy gate electrode positioned under the first insulating film and a second part of the dummy gate electrode at a bottom portion of the trench without removing;

after removing the exposed dummy gate electrode, forming a gate insulator over the surface of the fin region exposed in the trench;

depositing a gate electrode material over the gate insulator and over the first insulating film; and

polishing the gate electrode material over the first insulating film until the first insulating film is exposed to form a gate electrode.

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

forming an insulating cap layer before forming the dummy gate electrode, the apex portion of the fin region being covered with the insulating cap layer.

3. The semiconductor device manufacturing method according to claim 1 , further comprising:

implanting an impurity in the fin region using the dummy gate electrode as a mask to form a source/drain region.

4. The semiconductor device manufacturing method according to claim 3 , wherein forming the source/drain region comprises:

implanting a first impurity in the fin region using the dummy gate electrode as a mask;

forming a sidewall spacer in the sidewall portion of the fin region after implanting the first impurity; and

implanting a second impurity in the fin region using the dummy gate electrode and the sidewall spacer as masks.

5. The semiconductor device manufacturing method according to claim 3 , further comprising:

forming a silicide layer on a surface of the source/drain region.

6. The semiconductor device manufacturing method according to claim 1 , wherein the dummy gate electrode includes nitride silicon.

7. The semiconductor device manufacturing method according to claim 1 , wherein the gate electrode includes at least one of TiN and W.

8. The semiconductor device manufacturing method according to claim 1 , wherein the substrate is a semiconductor on insulator substrate.

9. The semiconductor device manufacturing method according to claim 1 , wherein the gate insulator is formed by laminating an oxide silicon film and an insulating film from at least one of the group consisting of a HfSiO film, a HfSiON film, a HfO 2 film, a HfAlO film, a HfAlON film, a LaO 2 film, a LaSiO film, and a LaAlO film.