Fully-Filled, Highly-Reliable Fine-Pitch Interposers with TSV Aspect Ratio >10 for Future 3D-LSI/IC Packaging

Si interposer with 10 mu m-width, 100 mu m-deep through-silicon via (TSV) has been fabricated using electroless (EL) Ni as barrier and seed layers, and characterized for their electrical resistance. The chemistry of electroless-Ni plating bath was meticulously adjusted for the conformal formation of Ni along the TSV side wall. From the resistance value of 36 m Omega per TSV obtained from the Kelvin measurement of these Cu-TSV chain showed that the electroless Ni layer well acts as a good seed layer for completely filling the high aspect ratio TSVs by Cu-electroplating.