Patent ID: 8669137
Filing Date: 2014-03-11
Classification: H01L

Abstract:
1. A method for forming a semiconductor flip chip from a wafer having solderable electrical conducting sites and a substrate having electrical connecting pads and electrically conductive posts operatively associated with said pads and extending away from said pads to terminate in distal ends, the steps comprising solder bumping said distal ends through openings in a solder mask by infection molding solder onto said distal ends to produce a solder bumped substrate and soldering said solder bumped substrate to said sites wherein said distal ends extend into said mask through said openings comprising: a. providing said substrate having said posts on said pads; b. providing said mask wherein said openings comprise a plurality of through hole reservoirs and aligning said reservoirs in said mask to be substantially concentric with said distal ends; c. injecting liquid solder into said reservoirs to provide a volume of liquid solder on said distal ends; d. cooling said liquid solder in said reservoirs to solidify said solder; e. removing said mask to expose said solidified solder after said cooling and thereby provide a solder bumped substrate; f. positioning said solder bumped substrate on said wafer in a manner that leaves a gap between said wafer and said substrate; g. abutting said posts and said sites and joining said wafer to said substrate by heating said solder to its liquidus temperature.