Semiconductor device
A semiconductor device includes a conductive layer formed on a silicon semiconductor substrate, cobalt silicide films formed in a surface layer of the conductive layer, an interlayer insulating film which covers the silicon semiconductor substrate thereabove, and a barrier metal film and a tungsten film which fill in a contact hole formed in the interlayer insulating film and is electrically connected to the cobalt silicide film. The positions of lower surfaces of the cobalt silicide films at the bottom of the contact hole are set lower than the position of a lower surface of the cobalt silicide film provided outside the contact hole. A cobalt silicide film having a necessary thickness can be ensured at the bottom of the contact hole. Further, a contact resistance can be reduced and a junction leak can be suppressed.
1. A semiconductor device comprising:
a first impurity diffusion layer formed in a surface layer of a semiconductor substrate;
a first low resistance film which contains metal formed in a surface layer of said first impurity diffusion layer;
an insulating film which covers said semiconductor substrate; and
a first conductive film which fills in a first opening formed in said insulating film and is electrically connected to said first low resistance film; and
a second low resistance film which contains metal formed beneath said first low resistance film and only at a bottom of said first opening,
wherein a position of a lower surface of said second low resistance film at the bottom of said first opening is lower than a position of a lower surface of said first low resistance film provided outside said first opening.
2. The semiconductor device according to claim 1 , wherein a thickness of said first and second low resistance films at the bottom of said first opening is different from the a thickness of said first low resistance film provided outside said first opening.
3. The semiconductor device according to claim 2 , wherein the thickness of said first and second low resistance films at the bottom of said first opening is thicker than the thickness of said first low resistance film provided outside said first opening.
4. The semiconductor device according to claim 1 , further comprising,
a second impurity diffusion layer formed in a surface layer of said semiconductor substrate in a region different from a region in which said first impurity diffusion layer is formed;
a pad electrode formed on said second impurity diffusion layer;
a third low resistance film formed in a surface layer of said pad electrode; and
a second conductive film formed on said pad electrode and electrically connected to said pad electrode via said third low resistance film.
5. The semiconductor device according to claim 4 , wherein the region in which said first impurity diffusion layer is formed, is a logic area, and the region in which said second impurity diffusion layer is formed, is a memory cell area.
6. The semiconductor device according to claim 4 , wherein said second conductive film is electrically connected to said pad electrode via a second opening formed in said insulating film, and wiring patterns each having the same thickness are respectively formed on said insulating film by said first conductive film and said second conductive film.
7. The semiconductor device according to claim 6 , wherein said first conductive film and said second conductive film are formed of the same material.
8. The semiconductor device according to claim 1 , further comprising a fourth low resistance film formed in a concave portion of the surface of said insulating film and different in resistivity from said first conductive film,
wherein said first conductive film extends over said fourth low resistance film and said insulating film as a predetermined pattern, and
said first conductive film including two films separated from each other on said fourth low resistance film and are electrically connected to each other via said fourth low resistance film.
9. The semiconductor device according to claim 1 , wherein said first conductive film is a laminated film in which a barrier metal film and a high melting-point metal film are laminated in this order from a lower layer.
10. The semiconductor device according to claim 4 , wherein said second conductive film is a laminated film in which a barrier metal film and a high melting-point metal film are laminated in this order from a lower surface.