Patent ID: 6692611
Filing Date: 2004-02-17
Classification: B32B,C08F,C09D,C09J,H01L

Abstract:
A method for preparing a soldered and underfilled flip chip assembly on a circuit substrate, the method comprising the steps of:a) providing 1) an integrated circuit chip having a surface comprising reflowable solder bumps with contact tips thereon, and 2) a printed circuit substrate having a bonding site, wherein at least one of said chip and said circuit substrate is transmissive to actinic radiation in an identified spectral region having wavelengths greater than 400 nm and up to 1200 nm, b) applying a photopolymerizable adhesive composition directly to one or both of the surface of the chip with solder bumps and the bonding site of the printed circuit substrate, said method providing exposure of said contact tips of said solder bumps of said chip, said photopolymerizable adhesive composition comprising a photopolymerizable moiety and a photoinitiator therefor, wherein said photopolymerizable composition absorbs radiation in said identified spectral region of said radiation transmissive chip or circuit substrate, c) aligning and pressing the exposed tips of the bumps on the surface of said chip against the bonding site of said circuit substrate, d) subjecting the flip chip assembly to heat at a temperature sufficient to melt and reflow the solder so as to establish electrical contact and a metallurgical bond between said chip and said circuit substrate, wherein the photopolymerizable material remains substantially uncured, and e) directing radiation within said identified spectral region through said radiation transmissive chip or circuit substrate for a time sufficient to cure said photopolymerizable adhesive composition and to produce said soldered and underfilled flip chip assembly on said circuit substrate.