Patent ID: 8371497

Claim:
A method to attach a die to a package substrate, the method comprising: applying a single continuous layer of flux resin having a thickness of approximately 5 to 15 micrometers to the package substrate, wherein pads are located on the package substrate, and wherein the flux resin covers the pads on the package substrate; dipping at least a portion of the die into solder paste; placing the dipped die onto the package substrate after applying the flux resin, wherein the at least a portion of the dipped die is placed directly onto the applied flux resin; and after placing the dipped die onto the package substrate to provide electrical connection between the die and the pads on the package substrate, reflowing the solder paste remaining on the portion of the die to attach the die to the package substrate, wherein underfill is applied between the dipped die and the package substrate after reflowing the solder paste.