Development of Bumpless Stacking With Bottom-Up TSV Fabrication

A 3-D integration technology using bump less stacking based on a new bottom up Cu electroplating method without backside Cu chemical-mechanical planarization removal is presented in this paper. The approach successfully achieves via plating without thick Cu overburden by probing unique bottom electrodes for different I/O ports of TSV without additional steps in the conventional processes. The concepts and fabrication processes are described in detail. The results obtained from through silicon via (TSV) daisy chains show excellent electrical characteristics and good reliability in leakage current measurement. The proposed approach therefore has potential for low-cost via-last 3-D integration.