Liner and barrier layer in dual damascene cu interconnect for enhanced EM and process
View Patent ↗A Cu interconnect and a method of forming a Cu interconnect of damascene process is provided. A barrier layer is formed at a sidewall and a bottom of a through hole and a groove, constructing a Cu interconnecting line. The barrier layer comprises a metal crystal adhesion layer or a graphene layer. The metal crystal adhesion layer may be a Co, Ru or Os crystal layer. The metal crystal adhesion layer may enhance adhesion of Cu, inhibit diffusion of Cu toward a dielectric layer efficiently, and promoting electro-migration of Cu. The graphene layer may be an Carbon allotrope/graphene complex layer. The graphene layer may provide lower resistance for the Cu interconnect and increase adhesion between barrier and dielectric layer to improve EM. Both the metal crystal adhesion layer and the graphene layer may efficiently reduce the total thickness of the barrier layer and the first barrier layer to efficiently decrease resistance of the through hole.
1. A copper (Cu) interconnect, forming in a through hole and a groove of a dielectric layer on a substrate, wherein the Cu interconnect comprises a barrier layer forming at a sidewall and a bottom of the through hole and a sidewall and a bottom of the groove and a Cu interconnecting line forming on the barrier layer and filling the through hole and groove, the barrier layer comprises a metal crystal adhesion layer, a first barrier layer is formed between the metal crystal adhesion layer the through hole and the groove, an amorphous metal pad layer is formed between the metal crystal adhesion layer and the first barrier layer, and the metal crystal adhesion layer is cobalt (Co) crystal layer, ruthenium (Ru) crystal layer or osmium (Os) crystal layer.
2. The Cu interconnect according to claim 1 , wherein a thickness of the metal crystal adhesion layer is within 1 nm˜5 nm.
3. The Cu interconnect according to claim 1 , wherein a metal crystal of the metal crystal adhesion layer is in hexagonal close-packed (HCP) crystal structure or face centered-cubic (FCC) crystal structure.
4. The Cu interconnect according to claim 1 , wherein the amorphous metal pad layer is amorphous Co layer, amorphous Ru layer or amorphous Os layer.
5. The Cu interconnect according to claim 4 , wherein a thickness of the amorphous metal pad layer is within 1 nm˜3 nm, a thickness of the metal crystal adhesion layer is within 1 nm˜2 nm.
6. The Cu interconnect according to claim 1 , wherein the first barrier layer is a tantalum nitride (TaN) layer or TaN/Ta multilayers.