Semiconductor device and manufacturing process therefor
View Patent ↗An objective of this invention is to provide a semiconductor device comprising a less bias-dependent capacitative element with a large capacity per a unit area, having a configuration which can be manufactured using an existing structure in a semiconductor device. There is provided a semiconductor device 100 , comprising a semiconductor substrate; a lower interconnection 101 on the semiconductor substrate, in whose upper surface a concave is formed; dielectrics 102 a, 102 b, 102 c, 102 d covering the inner surface of the concave; and a upper interconnection 104 on the dielectrics 102 a, 102 b, 102 c, 102 d.
1. A semiconductor device, comprising:
a semiconductor substrate;
a first metal film on the semiconductor substrate;
an insulating film disposed on the first metal film, wherein the insulating film includes a through hole whose tip is a concave in the upper surface of the first metal film;
a capacitor film covering the inner surface of the concave; and
a second metal film on the capacitor film.
2. The semiconductor device according to claim 1 , wherein the first metal film is a metal interconnection; and the second metal film is a metal plug.
3. The semiconductor device according to claim 1 , wherein
a plurality of the concaves are formed in the first metal film; and
a second metal film is formed on each of the capacitor films covering the inside of the plurality of concaves.
4. The semiconductor device according to claim 3 , further comprising a third metal film connected to each of the plurality of second metal films.
5. The semiconductor device according to claim 3 , wherein the third metal film is a metal interconnection.
6. The semiconductor device according to claim 1 , wherein the capacitor film comprises a metal oxide film, a metal nitride film or a metal oxynitride film.
7. The semiconductor device according to claim 6 , wherein the capacitor film comprises a film formed by oxidizing or nitriding the inner surface of the concave in the first metal film.
8. The semiconductor device according to claim 1 , wherein the first metal film comprises an Al- or Cu-containing metal film; and
the capacitor film comprises an Al oxide or Cu oxide, nitride or oxynitride film.
9. The semiconductor device according to claim 1 , wherein the capacitor film comprises a silicon oxide film, a silicon nitride film or a silicon oxynitride film.
10. The semiconductor device according to claim 1 , wherein the capacitor film comprises a film deposited on the inner surface of the first metal film by CVD or PVD.
11. The semiconductor device according to claim 1 , wherein the first metal film
and the insulating film are on separate layers of the semiconductor device with respect to a direction in which the insulator film is disposed on the first metal film.
12. A process for manufacturing a semiconductor device, comprising:
forming a first metal film on the upper surface of a semiconductor substrate;
forming an upper insulating film on the first metal film;
forming a through hole penetrating the insulating film, whose tip is a concave in the upper surface of the first metal film;
forming a capacitor film covering the inner surface of the concave in the first metal film; and
forming a second metal film on the capacitor film.
13. The process for manufacturing a semiconductor device according to claim 12 , further comprising the step of forming a third metal film connected to the second metal film on the insulating film and the second metal film.
14. The process for manufacturing a semiconductor device according to claim 11 , wherein the step of forming the capacitor film comprises oxidizing or nitriding the inner surface of the concave in the first metal film.
15. The process for manufacturing a semiconductor device according to claim 12 , wherein the step of forming the capacitor film comprises forming the capacitor film on the inner surface of the concave in the first metal film by CVD or PVD.
16. A capacitor comprising:
a first metal wiring;
an interlayer insulating film disposed on said first metal wiring, the interlayer insulating film having a plurality of holes therethrough, wherein the plurality of the holes extend into an upper surface of the first metal wiring defining a plurality of concaves in the upper surface of the first metal wiring;
a plurality of dielectric films each disposed on the upper surface of said first metal wiring in each of the plurality of the concaves;
a plurality of plugs each formed in the corresponding ones of said plurality of the concaves and said plurality of the holes;
and a second metal wiring formed on said interlayer insulating film and said plurality of the plugs;
and a second metal wiring formed on said interlayer and said plurality of plugs.