Low temperature Cu-Cu thermo-compression bonding with temporary passivation of self-assembled monolayer and its bond strength enhancement
Tan, Chuan Seng
Lim, Dau Fatt
Ang, X. F.
Leong, K. C.
Date of Issue2011
Singapore Institute of Manufacturing Technology
Self-assembled monolayer (SAM) of alkane-thiol is formed on copper (Cu) thin layer coated on silicon (Si) wafer with the aim to protect the surface against excessive oxidation during storage in the room ambient. After 3 days of storage, the temporary SAM layer is desorbed with in situ anneal in inert ambient to uncover the clean Cu surface. A pair of wafers is bonded at 250 °C. Clear evidences of in-plane and out-of-plane Cu grain growth are observed resulting in a wiggling bonding interface. This gives rise to enhancement in shear strength in the bonded Cusingle bondCu layer.
DRNTU::Engineering::Electrical and electronic engineering::Microelectronics
© 2011 Elsevier Ltd.