Semiconductor device with a line and method of fabrication thereof
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 semiconductor device comprising:
a first insulation film;
a Cu wiring provided in the first insulation film, including copper, and having a lower hole formed in the Cu wiring;
a second insulation film provided on the first insulation film;
a third insulation film provided on the second insulation film, the second insulation film and the third insulation film having an upper hole formed over the lower hole, wherein the lower hole extends underneath the second insulation film;
a first barrier metal provided along an internal wall surface of the upper hole;
a first conductive film provided along an internal wall surface of the first barrier metal in the upper hole and along the lower hole, wherein the first conductive film is different from the first barrier metal;
a conductive film containing copper and filling the upper and lower holes, and
a second barrier metal which includes a material of the first barrier metal, and is formed along an inner wall surface of the first conductive film,
wherein a lower end of the first barrier metal is higher than a lower end of the first conductive film,
wherein the lower hole narrows gradually from an upper portion of the lower hole to a lower portion of the lower hole, and
wherein the Cu wiring and the conductive film are separated by the second barrier metal.
2. The semiconductor device according to claim 1 , further comprising:
an upper wiring including copper;
a hole including a bottom portion reaches the upper wiring at a top portion of the upper wiring; and
a connection layer filling the hole, the hole failing to extend into the upper wiring,
wherein the hole is larger in diameter than the upper hole, and
wherein the hole overlies the upper hole.
3. The semiconductor device according to claim 1 , wherein the first barrier metal includes at least one selected from a group consisting of tantalum nitride, tantalum silicide, tantalum carbide, titanium nitride, titanium silicide, titanium carbide, tungsten silicide, tungsten carbide, ruthenium, and ruthenium oxide.
4. The semiconductor device according to claim 1 , the lower hole is cone shape or hemisphere shape.
5. The semiconductor device according to claim 1 , wherein the lower hole is formed in the first insulation film and the Cu wiring.
6. The semiconductor device according to claim 1 , wherein a depth of the lower hole is equal or more than 30 nm.
7. The semiconductor device according to claim 1 , wherein a diameter of the upper portion of the lower hole is smaller than a diameter of the upper hole.
8. The semiconductor device according to claim 1 , wherein a lower end of the first conductive film is higher than the lower end of the second barrier metal, and is lower than the lower end of the first barrier metal.
9. The semiconductor device according to claim 1 , wherein the conductive film has a side through the lower hole, and
wherein the Cu wiring and the side of the conductive film are separated by the second barrier metal.