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

Si interposer with 10 μm-width, 100 μm-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 ΩW 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.