Patent ID: 6566234
Filing Date: 2003-05-20
Classification: B23K,B32B,C09J,H01L,H05K

Abstract:
A method for making an electrical component assembly that comprises the steps of:(a) providing an integrated circuit device having an active surface having one or more solderable contacts with a plurality of discrete solder bumps such that said one or more solderable contacts has a solder bump associated therewith and electrically interconnected thereto, and applying to at least a portion of the active surface and solder bumps a first portion encapsulant; (b) providing a printed circuit substrate having a surface with a plurality of discrete metallized pads thereon, at least one pad corresponding to at least one solder bump on said integrated circuit device; (c) disposing a second portion encapsulant comprising a fluxing agent between the integrated circuit device and the printed circuit substrate; and (d) attaching the integrated circuit device to the printed circuit substrate to form a combined unit wherein the solder bumps face towards and are aligned with their corresponding pads, and there exists a thin layer of said second portion encapsulant at least between the solder bumps and the printed circuit substrate; wherein said first portion encapsulant comprises a chemical composition selected so as to not adversely affect properties of the second portion, said properties including i. a fluxing agent promoting wetting of the metallized pads by the solder; ii. chemically immobilizing the fluxing agent and flux reaction byproducts after cure; iii. having a low viscosity during a soldering operation that does not impede flow of molten solder; iv. resisting corrosion and resisting degradation at soldering temperatures; and v. not evolving any gases that can cause voids or bubbles.