A new built-up epoxy resin PCB technology for high density surface mount package and device attachment

A new technology has been developed comprising of high density printed circuit board materials fabricated with epoxy resin as the insulation material for enhancing high density surface mount assembly. The high density circuit board process is fabricated by a semi-additive plating method utilizing photo sensitive epoxy resin as the insulation material, and electroless and electrolytic copper plating for the conductors, Two design rule steps have been developed to stabilize the manufacturing process and to meet the market demand. Step 1 is designed with 100 μm via diameters with 50 μm line widths and spaces, while Step 2 is designed with 30 μm lines widths and spaces with 50 μm via diameters. Adhesive strength of conductor pad metalization has been validated on the dielectric layer. The thermal stresses resulting from flip chip assembly are controlled by the effects of micro anchors processed in the conductors of uniform size. Confirmed also is the environmental reliability of a substrate processed with 30 μm design rule line widths and spaces by the semi-additive plated method