Semiconductor device
View Patent ↗As etch-stop films or Cu-diffusion barrier films used in insulation films constituting conductor layers of a stacked structure, films having smaller dielectric constant than silicon nitride films are used, and an insulation film at a lower-layer part of the stacked structure is made to have smaller dielectric constant than that at an upper-layer part thereof, and further this insulation film is a silicon oxide (SiO) film and has, in the interior thereof, nano-pores of from 0.05 nm or more to 4 nm or less in diameter as chief construction. This makes it possible to dramatically reduce effective dielectric constant while keeping the mechanical strength of the conductor layers themselves, and can materialize a highly reliable and high-performance semiconductor device having mitigated the wiring delay of signals which pass through wirings.
1. A semiconductor device comprising:
a semiconductor substrate;
MOS transistors formed on said semiconductor substrate;
a plurality of layers of wiring structure positioned over said MOS transistors and each wiring structure comprising a first insulating film, a second insulating film formed over said first insulating film, a first wiring layer formed in said first insulating film, and a second wiring layer comprising copper material, formed in said second insulating film; and
a rewiring interconnection positioned over said plurality layers of wiring structure, having an outer lead connection in a part thereof;
wherein an uppermost wiring structure among said plurality layers of said wiring structure has a third insulating film formed between said first insulating film and said second insulating film of said uppermost wiring structure, having a dielectric constant higher than a dielectric constant of said second insulating film of said uppermost wiring structure,
said outer lead connection is positioned above said second insulating film of said uppermost wiring structure in cross-sectional view, and
said second insulating film of said uppermost wiring structure has higher dielectric constant than that of said second insulating film of a predetermined layer of wiring structure which is positioned lower than said uppermost wiring structure.
2. A semiconductor device according to claim 1 , wherein said second insulating film of said uppermost wiring structure is fluorine-doped silicon oxide.
3. A semiconductor device according to claim 1 , wherein said second insulating film of said predetermined layer of wiring structure has a dielectric constant less than 2.5.
4. A semiconductor device according to claim 1 , wherein said predetermined layer of wiring structure has a fourth insulating film over said second insulating film of said predetermined layer of wiring structure;
said fourth insulating film has a dielectric constant higher than that of said second insulating film of said predetermined layer of wiring structure; and
said second wiring layer of said predetermined layer of wiring structure is formed to extend through thickness direction of said second and fourth insulating films.
5. A semiconductor device according to claim 1 , further comprising:
a resin encapsulation which covers said semiconductor substrate;
outer lead having a part thereof exposed from said resin encapsulation, electrically connected to said outer lead connection.
6. A semiconductor device according to claim 1 , further comprising:
a fifth insulating film positioned between said uppermost wiring structure and said rewiring interconnection;
wherein said fifth insulating film comprises a polyimide insulation film.
7. A semiconductor device according to claim 1 , wherein all regions of said outer lead connection are vertically above said second insulating film of said uppermost wiring structure in cross-sectional view.
8. A semiconductor device according to claim 1 , wherein all regions of said outer lead connection are above said second insulating film of said uppermost wiring structure and offset from said second wiring layer of said uppermost wiring structure in cross-sectional view.