Semiconductor device with a line and method of fabrication thereof
View Patent ↗A semiconductor device includes an interlayer insulation film, an underlying line provided in the interlayer insulation film, a liner film overlying the interlayer insulation film, an interlayer insulation film overlying the liner film. The underlying line has a lower hole and the liner film and the interlayer insulation film have an upper hole communicating with the lower hole, and the lower hole is larger in diameter than the upper hole. The semiconductor device further includes a conductive film provided at an internal wall surface of the lower hole, a barrier metal provided along an internal wall surface of the upper hole, and a Cu film filling the upper and lower holes. The conductive film contains a substance identical to a substance of the barrier metal. A highly reliable semiconductor device can thus be obtained.
1. A method of fabricating a semiconductor device, comprising the steps of
forming an lower wiring layer including a first insulation film and a Cu wiring which is formed in said first insulating film and includes copper;
depositing a second insulating film on said first insulating film and said Cu wiring;
depositing a third insulating film on said second insulating film;
forming an upper hole in said second and third insulation films, said upper hole reaching said Cu wiring;
wet-etching an interior of said upper hole to form a lower hole in said Cu wiring, said lower hole communicating with said upper hole;
depositing an upper conductive film covering an inner wall surface of said upper hole and a bottom of said lower hole;
physically etching said upper conductive film and said Cu wiring which are present at said bottom of said lower hole to provide a lower conductive film on an inner wall surface of said lower hole; and
depositing a conductive film containing copper and filling said upper and lower holes.
2. The method according to claim 1 , wherein the step of physically etching includes physical etching until said Cu wiring is penetrated.
3. The method according to claim 2 , wherein said upper conductive film is a barrier metal including a predetermined material, and
wherein said lower conductive film includes said predetermined material and copper.
4. The method according to claim 1 , wherein the step of forming said upper hole includes forming said upper hole reaching said Cu wiring and said first insulation film.
5. The method according to claim 1 , wherein said lower hole is larger in diameter than said upper hole.