Demonstration of Low Cost TSV Fabrication in Thick Silicon Wafers

Low cost wafer-level chip-scale vacuum packaging (WLCSVP) imposes unique constraints on potential implementation of through-silicon vias (TSVs). A WLCSVP requires a relatively thick substrate to prevent mechanical failure. Two approaches for integrating TSVs in thick silicon wafers have been successfully demonstrated. Both approaches enable TSV formation from the backside of a device wafer and are compatible with the requirements of subsequent packaging operations. We achieved low contact resistance between TSVs and frontside Ti/Cu and Al metallization, while demonstrating high isolation resistance and high TSV yield.