Method of forming an interconnect structure

Claim 1

A method of filling an interconnect structure, wherein the interconnect structure has sides, the method comprising the steps of: providing the interconnect structure wherein the interconnect structure has a top opening having a first dimension and a bottom opening having a second dimension, the first dimension being greater than the second dimension: forming a barrier layer on the sides of the interconnect structure, wherein the barrier layer is formed at a temperature below about 400° C.; forming a first conductive layer overlying the barrier layer and in the interconnect structure, wherein the first conductive layer comprises aluminum and is formed at a temperature below about 400° C.; forming a second conductive layer overlying the first conductive layer and in the interconnect structure, wherein the second conductive layer comprises aluminum and copper and is formed at a temperature below about 400° C.; and annealing the second conductive layer at a temperature below about 400° C. so that copper from the second conductive layer is diffused into the first conductive layer, whereby none of the barrier layer, the first conductive layer, and the second conductive layer are ever exposed to a temperature greater than about 400° C. in the steps of forming and annealing: polishing portions of all of the barrier layer, the first conductive layer, and the second conductive layer together to form a conductive interconnect structure which contains portions of all of the barrier layer, the first conductive layer, and the second conductive layer as part of the conductive interconnect structure.

Claim 2

A method of filling an interconnect structure, wherein the interconnect structure has sides, the method comprising the steps of: providing the interconnect structure wherein the interconnect structure has a top opening having a first dimension and a bottom opening having a second dimension, the first dimension being greater than the second dimension: forming a barrier layer on the sides of the interconnect structure, wherein the barrier layer is formed at a temperature below about 400° C.; forming a first conductive layer overlying the barrier layer and in the interconnect structure, wherein the first conductive layer comprises aluminum and is formed at a temperature below about 400° C.; forming a second conductive layer overlying the first conductive layer and in the interconnect structure, wherein the second conductive layer comprises aluminum and copper and is formed at a temperature below about 400° C.; and annealing the second conductive layer at a temperature below about 400° C. so that copper from the second conductive layer is diffused into the first conductive layer, whereby none of the barrier layer, the first conductive layer, and the second conductive layer are ever exposed to a temperature greater than about 400° C. in the steps of forming and annealing: polishing portions of all of the barrier layer, the first conductive layer, and the second conductive layer together to form a conductive interconnect structure which contains portions of all of the barrier layer, the first conductive layer, and the second conductive layer as part of the conductive interconnect structure.