Moisture resistant aluminum nitride filler for high thermal conductivity microelectronic molding compounds

Abstract

A patented moisture resistant aluminum nitride filler has been developed for use in high thermal conductivity microelectronic molding compounds. Molding compounds based on biphenyl resin and using this filler show high thermal conductivity (4.5 W/mK), low coefficient of thermal expansion (16 ppm //spl deg/C), good flowability, high strength, moderate abrasion, and device reliability comparable to standard fused silica systems. Finite Element Analysis of a TO220 device using transient thermal stress shows approximately a 41% and 64% reduction respectively for Theta ja and Theta jc, assuming an aluminum nitride molding compound of 3.2 W/mK. Experimental thermal measurements on a 208 lead PQFP (no heat sink) molded with an ECN based molding compound (3.4 W/mK) yielded a 21% reduction in Theta ja and a 61% reduction in Theta jc.