Patent ID: 8580688

Claim:
A method for forming a copper interconnection structure, the method comprising the steps of: forming an insulating layer over a main body; forming a copper layer including manganese on the insulating layer; annealing the copper layer including manganese so as to form a diffusion barrier layer, wherein the annealing step is applied: in a vacuum atmosphere with a pressure of not more than 0.1 Pa, at temperatures ranging from 350° C. to 550° C., and for a time period ranging from 5 to 80 minutes; and depositing copper over the diffusion barrier layer so as to form an interconnection body, wherein the diffusion barrier layer comprises an oxide layer including manganese having a compositional ratio of oxygen to manganese (y/x) less than 2; further comprising a step of annealing an upper surface of the interconnection body after the depositing step so as to form a second oxide layer on the upper surface of the interconnection body; wherein a compositional ratio of oxygen to manganese in the second oxide layer (y 1 /x 1 ) is greater than the compositional ratio of oxygen to manganese in the diffusion barrier layer (y/x).