Domed and Released Thin-Film Construct—An Approach for Material Characterization and Compliant Interconnects

An approach for microfabricating precisely defined spherical 3-D domes through a simple low-temperature polymer reflow process was developed. Release of a thin metal film patterned over the domed structure was accomplished by the removal of the underlying polymer using two different methods: dry thermal decomposition and wet supercritical release. The domed shape impacted the effect of stiction during the release step and assisted in the release of large millimeter-size film geometries. The dome and release procedures were used to fabricate an experimental test specimen that functions as either a tensile or interfacial fracture test for thin films on rigid substrates. Other potential applications of the domed metal structures such as compliant electrical interconnects are discussed.