Method for galvanic forming of bonding pads

Claim 1

Method for the preparation of at least one bump structure on a surface of a substrate for bonding purposes, comprising the steps of (a) providing a metallic bond pad on said substrate, said metallic bond pad having a first thickness; (b) providing a metallic underbump metallization comprising: (i) selectively applying a first metallic layer having a second thickness onto only said metallic bond pad by a first electroless deposition, providing an adhesion and diffusion barrier with respect to said bond pad inside said at least one bump structure; (ii) providing a passivation outside of said at least one metallic bond pad, covering the surface of the substrate, a surface of said passivation being activated prior to the application of a plating base by a second electroless deposition onto said activated passivation substantially throughout the whole activated surface of said passivation and said selectively applied first metallic layer, said plating base having a third thickness; (c) providing a photosensitive resist layer, having a fourth thickness, related to a predetermined height of said at least one bump structure; (d) providing at least one opening in said photosensitive resist layer at a position said at least one metallic bond pad is provided on the substrate; (e) electrodepositing a metal into said at least one opening, to control the growth of an upper bump portion said at least one bump structure and thus form and shape an electrodeposited upper bump portion onto said electroless deposited underbump metallization and provide said at least one bump structure.