Patent ID: 7098126
Filing Date: 2006-08-29
Classification: H01L,H05K

Abstract:
1. A method of forming electroplated solder on an organic circuit board for attaching an IC chip, comprising: providing an organic circuit board including a surface bearing electrical circuitry that includes at least one contact pad; forming a solder mask layer that is placed on the board surface and patterned to expose the contact pad; coating the surfaces of the solder mask layer and the contact pad with aqueous solutions which at least contains copper ions followed by reduction of the copper ions; forming a first thin non-noble metal layer that is deposited by electroless plating over the board surface; forming a second thin metal layer that is deposited by electroplating over the first thin metal film; forming a resist layer over the second thin metal layer, and forming at least one opening located at the contact pad; forming a solder material in the opening by electroplating; removing the resist layer, and then removing the first and second thin metal layers beneath the resist layer; and reflowing the solder material to form a solder bump, wherein the first and second thin metal layers beneath the solder bump are dissolved completely into the solder bump.