A new aramid/epoxy laminate for advanced SMT

A new aramid/epoxy laminate for use in advanced surface mount technology has been developed. The laminate consists of paper from PPODTA (co-poly-paraphenylene 3,4´-oxydiphenylene terephthalamide) and epoxy resin with high purity and high temperature resistance. Because the laminate is designed and processed to have minimum impurities, high glass transition temperature, and high dimensional stability, the laminate can be used as a substrate for LCCC, COB, flip chip, PGA, TAB, and other advanced surface mount technologies. The laminate is among the most reliable for electromigration between surface conductors, between plated-through barrels, and between opposed conductors. These properties are related to the purity and high temperature resistance of both the reinforcement material and the resin. Drilling, chemical treatment, and plating technologies lengthen the life of plated-through holes to thermal shocks. Applications to multilayer boards were also investigated by putting a stress on registration behaviors of the boards. The better registration of the new laminate was attributed to lower thermal expansion and higher temperature resistance than those of conventional FR-4 laminates