Preliminary Characterisation of Low-Temperature Bonded Copper Interconnects for 3-D Integrated Circuits
Author(s)Leong, Hoi Liong; Gan, C.L.; Pey, Kin Leong; Tsang, Chi-fo; Thompson, Carl V.; Hongyu, Li; ... Show more Show less
Three dimensional (3-D) integrated circuits can be fabricated by bonding previously processed device layers using metal-metal bonds that also serve as layer-to-layer interconnects. Bonded copper interconnects test structures were created by thermocompression bonding and the bond toughness was measured using the four-point test. The effects of bonding temperature, physical bonding and failure mechanisms were investigated. The surface effects on copper surface due to pre-bond clean (with glacial acetic acid) were also looked into. A maximum average bond toughness of approximately 35 J/m² was obtained bonding temperature 300 C.
Advanced Materials for Micro- and Nano-Systems (AMMNS);
three dimensional integrated circuits, bonded copper interconnects, bonding, fabrication