A multilevel epoxy substrate for flip-chip hybrid multichip module applications

A multilayer organic substrate is described. The multiple multilayer is comprised of two portions: one is thicker than the other, reinforced by organic fiber in each layer; and the other is a thick film that is not reinforced by organic fiber and forms low dielectric constant layers. A sophisticated epoxy resin provides the two-dimensional support with adhesion strength between the epoxy layer, thus stabilizing the elongation, shrinking, and warpage by an order of magnitude smaller compared to the conventional FR-4 substrate with inorganic reinforcement. The resin of an aromatic-amine additive type can lower the dielectric constant suitable for high frequency circuit performance and be an excellent acceptor of both adhered copper foil and copper-plated electrodes keeping a minimum width of 25-50 mu m. This two-portion substrate enables the use of flip-chip bonding on thick-film hybrid circuits, thus providing the necessary characteristic impedance of the semiconductor circuit, while maintaining compatibility with wire bonding and reflow soldering processes. >