Patent ID: 7726544
Filing Date: 2010-06-01
Classification: H01L,H05K

Abstract:
1. A method of forming pre-solders on a substrate, comprising: providing a substrate, wherein the substrate comprises an upper surface and a lower surface, a plurality of upper-surface metal circuits are formed on the upper surface; forming an upper-surface solder mask on the substrate to cover parts of the upper-surface metal circuits and parts of the upper surface for exposing a plurality of upper-surface pads on parts of the upper-surface metal circuits; forming a patterned photo-resist film on the upper-surface of the mask, wherein the patterned photo-resist film has a plurality of openings for exposing the upper-surface pads; forming a plurality of metal materials in the openings by printing after the step of forming the patterned photo-resist film; reflowing the metal materials after the step of forming the metal materials in the openings, so as to form a plurality of pre-solders on the upper-surface pads, wherein the pre-solders directly contact with the upper-surface solder mask and cover parts of an upper-surface of the upper-surface solder mask, and each of the pre-solders is spaced apart from the patterned photo-resist film by an interval so as not to contact the patterned photo-resist film; and removing the patterned photo-resist film after the step of reflowing the metal materials while reserving the upper-surface solder mask on the substrate.