Patent ID: 8026613
Filing Date: 2011-09-27
Classification: H01L

Abstract:
1. An interconnection structure suitable for flip-chip attachment of microelectronic device chips to packages, comprising: a two-layer ball-limiting composition comprising an adhesion/reaction barrier layer, wherein the adhesion/reaction barrier layer serves both as an adhesion and reaction barrier layer, and a solder wettable layer, said adhesion/barrier layer being for placement between a microelectronic device and said solder wettable layer, and wherein said solder wettable layer is of a metal reactive with components of a tin-containing lead-free solder, so that said solder wettable layer is consumed during soldering, wherein the adhesion/reaction barrier layer remains after being placed in contact with said lead free solder during soldering; and one or more lead-free solder balls selectively situated on said solder wettable layer, said lead-free solder balls comprising tin as a predominant component and one or more alloying components; wherein said adhesion/reaction barrier layer is comprised of a material selected from the group consisting of Zr, and ZrN.