Method for manufacturing semiconductor integrated circuit device
View Patent ↗Disclosed is a technique for reducing the leak current by reducing contamination of metal composing a polymetal gate of a MISFET. Of a polycrystalline silicon film, a WN film, a W film, and a cap insulating film formed on a gate insulating film on a p-type well (semiconductor substrate), the cap insulating film, the W film, and the WN film are etched and the over-etching of the polycrystalline silicon film below them is performed. Then, a sidewall film is formed on sidewalls of these films. Thereafter, after etching the polycrystalline silicon film with using the sidewall film as a mask, a thermal treatment is performed in an oxidation atmosphere, by which a light oxide film is formed on the sidewall of the polycrystalline silicon film. As a result, the contamination on the gate insulating film due to the W and the W oxide can be reduced, and also, the diffusion of these materials into the semiconductor substrate (p-type well) and the resultant increase of the leak current can be prevented.
1. A semiconductor integrated circuit device, comprising:
(a) a semiconductor substrate having a main surface;
(b) a first insulating film formed on the main surface of the semiconductor substrate;
(c) a silicon film formed on the first insulating film, which has a first sidewall positioned adjacent to the first insulating film and a second sidewall positioned apart from the first insulating film;
(d) a refractory metal film formed above the silicon film and having a third sidewall;
(e) a second insulating film formed over the second and third sidewall;
(f) a third insulating film formed on the first sidewall;
(g) a fourth insulating film formed on the refractory metal film and having a sidewall; and
(h) a fifth insulating film formed over the second and third insulating film.
2. The semiconductor integrated circuit device according to claim 1 ,
wherein the first and third insulating film are silicon oxide films, and the second insulating film is a silicon nitride film.
3. The semiconductor integrated circuit device according to claim 1 ,
further comprising a diffusion barrier film between the silicon film and the refractory metal film, wherein the diffusion barrier film includes a refractory metal nitride film.
4. The semiconductor integrated circuit device according to claim 1 ,
wherein the refractory metal film is selected from tungsten or molybdenum film.
5. The semiconductor integrated circuit device according to claim 1 ,
wherein the fourth insulating film is a silicon nitride film.
6. The semiconductor integrated circuit device according to claim 1 ,
wherein the second, the fourth, and the fifth insulating film are silicon nitride films.
7. A semiconductor integrated circuit device, comprising:
(a) a semiconductor substrate having a main surface;
(b) a first insulating film formed on the main surface of the semiconductor substrate;
(c) a silicon film formed on the first insulating film, which has a first sidewall positioned adjacent to the first insulating film and a second sidewall positioned apart from the first insulating film;
(d) a refractory metal film formed above the silicon film and having a third sidewall;
(e) a second insulating film formed over the second and the third sidewall;
(f) a third insulating film formed on the first sidewall;
(g) a fourth insulating film formed on the refractory metal film and having a sidewall;
(h) a fifth insulating film formed over the second and the third insulating film; and
(j) a contact plug disposed between the fifth insulating films, which is electrically connected to the substrate.
8. The semiconductor integrated circuit device according to claim 7 ,
wherein the first and the third insulating film are a silicon oxide films, and the second insulating film is a silicon nitride film.
9. The semiconductor integrated circuit device according to claim 7 ,
further comprising a diffusion barrier film between the silicon film and the refractory metal film, wherein the diffusion barrier film includes a refractory metal nitride film.
10. The semiconductor integrated circuit device according to claim 7 ,
wherein the refractory metal film is selected from tungsten or molybdenum film.
11. The semiconductor integrated circuit device according to claim 7 ,
wherein the fourth insulating film is a silicon nitride film.
12. The semiconductor integrated circuit device according to claim 7 ,
wherein the second, the fourth, and the fifth insulating film are silicon nitride films.
13. The semiconductor integrated circuit device according to claim 7 ,
wherein the contact plug includes polycrystalline silicon.
14. The semiconductor integrated circuit device according to claim 7 ,
further comprising a diffusion barrier film between the silicon film and the refractory metal film, wherein the diffusion barrier film includes a conductive member selected from titanium nitride or tungsten nitride film.