Silicon Interposers Enable High Performance Capacitors

Thin film capacitors without TSVs have been used previously. However, with the interconnect inductance being high, benefits of thin film capacitors have not been fully realized. TSV interposers with embedded capacitors provide the shortest electrical path between devices and power supply decoupling capacitors. TSVs with their very low inductance interconnects thus will enable very high electrical performance when integrated with embedded thin film capacitors. ALLVIA, on behalf of it's foundry customers, has been conducting studies of various capacitors on silicon interposers. The data presented in this paper shows after several thermal cycles that planar capacitors on silicon results in stable, reliable capacitors operating at very high frequencies. Unlike an issue of parallel resonance seen with chip capacitors, planar capacitors in interposers don't exhibit this property.