Microwave/millimeter wave circuit structure with discrete flip-chip mounted elements, and method of fabricating the same

Abstract From the Canadian patent

A microwave/millimeter wave circuit structure supports discrete circuit elements (2) by flip-chip mounting to an interconnection network (10) on a low cost non-ceramic and non-semiconductor dielectric substrate (2) preferably , Duroid. The necessary precise alignment of the circuit elements with contact pads (14) on the substrate network required for the high operating frequencies is facilitated by oxidizing (20) the interconnection network but providing , the contact pads from a non-oxidizable material (14') to establish a preferential solder bump (8) wetting for the pads. Alternately the contact , bumps on the flip-chips can be precisely positioned through corresponding openings …