Patent ID: 8921221

Claim:
A method comprising the steps of: obtaining an assembly comprising a substrate, a plurality of rows of electrically conductive contact pads on the substrate, a layer of solder resist on the substrate, and a plurality of first openings in the solder resist above and in fluid communication with the contact pads; applying a dry film layer of photoresist on the layer of solder resist; forming a plurality of second openings in the dry film layer above and in fluid communication with the contact pads; injecting flux-free molten solder into said first and second openings such that the molten solder interfaces with the contact pads and extends above the layer of solder resist; allowing the molten solder to solidify; removing the dry film layer from the layer of solder resist; and curing the dry film layer by heat treatment prior to injecting flux-free molten solder into the first and second openings, wherein the dry film layer has a relatively strong adhesion to a peripheral area of the substrate relative to an inner area of the substrate including the contact pads.