A new coiled microspring contact technology

A new contact technology has been developed using coiled microsprings for making highly compliant and independent electrical contacts to chips and package. The technology uses wafer-stage fabrication only, and is based on the formation of looped microsprings by irreversible thermal curving of thin film metal bimorphs. High contact forces can be used for making temporary or permanent planar contact with intrinsic scrub action. Microsprings have been made with coil diameters in the range 30 /spl mu/m to over 200 /spl mu/m. Coils 60 /spl mu/m diameter respond to forces in the 1-50 mN (0.1-5g) range with up to 10 /spl mu/m elastic compression.