Three dimensional interconnects with high aspect ratio TSVs and fine pitch solder microbumps

Abstract

High density three dimensional (3D) interconnects formed by high aspect ratio through silicon vias (TSVs) and fine pitch solder microbumps are presented in this paper. The aspect ratio of the TSV is larger than 10 and filled with Cu without voids; there are electrical nickel and immersion gold (ENIG) pads on top of the TSV as under bump metallurgy (UBM) layer. On the Si chip, Cu/Sn solder microbumps with 16µm in diameter and 25µm in pitch are fabricated. After singulating the Si chip and the Si carrier, there are joined together and the interconnection is formed between them through the solder micro bumps and the TSV.