A double-lithography and double-reflow process and application to multi-pitch multi-height mechanical flexible interconnects

Wafer-level multi-pitch and multi-height mechanically flexible interconnects (MPMH MFIs) are demonstrated using a double-lithography and double-reflow process of a large array of sacrificial polymer domes with various heights (ranging from 26 mu m to 66 mu m). Using these domes, NiW MFIs with various pitches (ranging from 50 mu m to 150 mu m) are formed atop the multi-height domes using electroplating. The mechanical and electrical properties of the fabricated MPMH MFIs are characterized using indentation and four-point resistance measurements.