Patent ID: 6050481
Filing Date: 2000-04-18
Classification: B23K,H01L,H05K,Y02P

Abstract:
A method of forming a solder ball structure comprising the steps of:a) obtaining a first object having at least one high melting point solder ball, wherein at least one of said high melting point solder ball has a corresponding ball limiting metallurgy structure (BLM) having a top and bottom and containing a low melting point solder, and wherein said solder ball has an outer surface, a top and a bottom and wherein the bottom of said solder ball in contact with the top of the corresponding BLM over a portion of the outer surface and wherein the bottom of said BLM in electrical communication with the first object;b) obtaining a template having a first surface;c) applying at least one disjoint area of low melting point solder paste to the first surface of the template;d) engaging the top of each at least one solder ball and the solder paste; ande) reflowing the solder ball and the disjoint area of solder paste while the solder ball and the disjoint area of solder paste are interacted, wherein the high melting point solder ball is coated with the low melting point solder over substantially all of the surface of the high melting point solder ball not in contact with the BLM; andf) disengaging the template from the solder ball structure.