Patent ID: 6872590

Claim:
A method of manufacturing a package substrate for electrolytic leadless plating, comprising the following steps of: (a) copper plating a whole surface of a base substrate having a plurality of through-holes defined in a copper clad laminate; (b) laminating a first dry film on the copper plated through-holes, followed by developing the laminated dry film; (c) etching a copper foil not covered with the first dry film so that an upper portion and a lower portion of the base substrate are patterned; (d) stripping the first dry film, followed by coating, exposing and developing a second dry film on the base substrate so that only the upper portion of the base substrate to be subjected to electrolytic Au plating is exposed; (e) grounding an electrolytic Au plating terminal to a solder ball pad, followed by Ni—Au plating a wire bonding pad through the through-holes; (f) removing the second dry film by use of a stripping solution; (g) coating, exposing and developing a third dry film on the substrate to pattern the solder ball pad; (h) removing a copper foil not covered with the third dry film by use of an etching solution, to form circuit patterns; (i) removing the third dry film by use of a stripping solution; (j) applying a solder resist onto a predetermined portion of the substrate, which is exposed, developed and then dried; and (k) coating an organic solderability preservative on the solder ball pad for metal finishing of the solder ball pad.