Novel Photo-Defined Polymer-Enhanced Through-Silicon Vias for Silicon Interposers

This paper presents a silicon interposer interconnection solution featuring novel electrical and optical through-silicon vias (TSVs). The copper-based electrical TSVs include polymer-clad TSVs and polymer-embedded vias (copper vias embedded in polymer wells within a low resistivity silicon substrate). Fabrication of the novel electrical TSVs is shown along with high-frequency measurements for polymer-embedded vias. Optical TSVs are fabricated in parallel with the polymer-clad TSVs to provide chip-to-motherboard optical access at the 850-nm wavelength. Optical loss measurements are performed for the fabricated optical TSVs.