Patent ID: 7732253

Claim:
A method comprising: forming a plurality of metallic posts on a flip-chip die, each metallic post having an exposed tip; forming a flash tin tip layer on the exposed tip of each metallic post; forming a plurality of solder bumps on a substrate, wherein the plurality of solder bumps are positioned to align with the plurality of metallic posts on the flip-chip die; after forming the flash tin tip layer on the exposed tip of each metallic post, positioning the flip-chip die over the substrate such that the flash tin tip layer of each of the plurality of metallic posts on the flip-chip die contacts a corresponding one of the plurality of solder bumps on the substrate; and heating the plurality of solder bumps to cause each one of the plurality of solder bumps to reflow and attach to the flash tin tip layer of each of the plurality of metallic posts when the plurality of solder bumps cool such that each metallic post contains no solder and solder is not placed on the exposed tips prior to positioning the flip-chip die over the substrate and heating the plurality of solder bumps.