Electrical and Reliability Investigation of Cu TSVs With Low-Temperature Cu/Sn and BCB Hybrid Bond Scheme

A wafer-level 3-D integration scheme using Cu through-silicon vias (TSVs) and fine-pitch Cu/Sn-BCB hybrid bonding was developed and investigated with electrical characterization and reliability assessment. The hybrid bonding could be achieved below 250 °C. Low Kelvin resistance and stable daisy chain resistance were achieved in 5- and 10- μm TSV test structures across the whole wafer. Without obvious deterioration in reliability test results, the integrated Cu TSV and hybrid bond scheme can be potentially designed for 3-D integration applications.