A method of assembling a semiconductor flip chip comprising a wafer having solderable electrical conducting sites and a substrate having electrical connecting pads and electrically conductive posts operatively associated with the pads and extending away from the pads to terminate in distal ends, comprises the pre-assembly steps of solder bumping the distal ends through openings in a solder mask by injection molding solder onto the distal ends so that the distal ends extend into the mask through the openings to produce a solder bumped substrate, and soldering the solder bumped substrate to the sites.