Ultrafine pitch (6-µm) evolution of Cu-Cu bonded interconnects in 3D wafer-on-wafer stacking

• Main Authors: Peng, L., Zhang, L., Li, H. Y., Fan, Ji, Lim, Dau Fatt, Tan, Chuan Seng
• Other Authors: School of Electrical and Electronic Engineering
• Format: Conference or Workshop Item
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: https://hdl.handle.net/10356/97644; http://hdl.handle.net/10220/12069
• Institution: Nanyang Technological University

In this paper, we successfully demonstrate ultrahigh density (>; 10^6 cm^-2) Cu-Cu interconnects of 6-μm pitch using wafer-on-wafer thermo-compression bonding. This is a significant improvement from our previous achievement of 15-μm pitch. In addition, we integrate Cu sealing frame with excellent helium leak rate to the bonded structures to promote the overall bond reliability. On top of that, temporary passivation of Cu surface using self-assembled monolayer (SAM) enhances the resistance against oxidation and particle contamination. Finally, thermal cycling test confirmed the thermal stability of the Cu-Cu daisy chain structure up to 1,000 cycles. Hence, this work opens up new opportunity for wafer level integration of Cu-Cu bonding with state-of-the-art TSV technology, enabling future ultrahigh density 3D IC applications.