adhesive

Ethoxyethyl α-cyanoacrylate was synthesized by first making oligo(ethoxyethyl α-cyanoacrylate) through a condensation reaction of ethoxyethyl cyanoacetate with paraformaldehyde, followed by a depolymerization of the oligomer at an elevated temperature in an acidic atmosphere with a high vacuum. The ethoxyethyl cyanoacetate was in turn synthesized from an esterification of ethoxyethanol and cyanoacetic acid. The molecular structure of the target monomer and the corresponding intermediates were corroborated by IR and 1H-NMR.

The dominant trend in packaging DDR DRAM for the future is the face down substrate-on-chip configuration. For this type of package it is critical that the die attach method employed provide precise control of bond line thickness and die tilt, minimal fillet, and prevent contamination of the wire bond pads located on the edge of the center wire bond channel. To date, a film adhesive has been the die attach method of choice because it is well suited to meet those requirements.

The present work demonstrates feasibility of an inkjettable, isotropically electrically conductive adhesive in the form of a silver loaded resin with a 2-step curing mechanism. In the first step, the adhesive is dispensed (jetted) and precured leaving a “dry” surface. The second step consists of assembly and final curing. The 2-step cure system is based on a Acrylate-Epoxy-Resin matrix with very low viscosity, i.e., 3 mPas of newtonian properties. Spheroidal silver particles of high purity and a compatible organic coating have been loaded at 70% by weight.