Cu pillar bump with non-metal sidewall protection structure

摘要

A sidewall protection structure is provided for covering at least a portion of a sidewall surface of a bump structure, in which a protection structure on the sidewalls of a Cu pillar and a surface region of an under-bump-metallurgy (UBM) layer is formed of at least one non-metal material layers, for example a dielectric material layer, a polymer material layer, or combinations thereof.