Texture and stress analysis of 120 nm copper interconnects

Abstract

A scanning transmission electron microscope diffraction technique was used to determine the local orientation of copper grains in 120 nm copper interconnect (CI) lines. These grains exhibit a normal orientation while the and the type orientations are present along the length and width of the CI line, respectively. Stresses, as high as 625 MPa, are present at the copper/diffusion barrier triple junctions that in conjunction with large stress gradients may induce stress-induced void formation upon thermal cycling.