Barrier film for flexible copper substrate and sputtering target for forming barrier film

摘要

A barrier film for a flexible copper substrate comprising a Co—Cr alloy film containing 5 to 30 wt % of Cr and a balance of unavoidable impurities and Co is provided. The barrier film has a thickness of 3 to 150 nm and a film thickness uniformity of 10% or less at 1&sgr;. A sputtering target for forming a barrier film comprising a Co—Cr alloy containing 5 to 30 wt % of Cr and a balance of unavoidable impurities and Co is also provided. The relative magnetic permeability in the in-plane direction of the sputtered face of the target is 100 or less. The barrier film for a flexible copper substrate and the sputtering target for forming such barrier film have a film thickness that is thin enough to prevent film peeling and inhibiting the diffusion of copper to a resin film such as polyimide, is capable of obtaining a sufficient barrier effect even in a minute wiring pitch and has barrier characteristics that will not change even when the temperature rises due to heat treatment or the like.