Low-temperature direct copper-to-copper bonding enabled by creep on highly (111)-oriented Cu surfaces

• Published in: Scripta materialia Vol. 78-79; pp. 65 - 68
• Main Authors: Liu, Chien-Min, Lin, Han-wen, Chu, Yi-Cheng, Chen, Chih, Lyu, Dian-Rong, Chen, Kuan-Neng, Tu, K.N.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2014
• Subjects: BONDING; Copper; Creep; Creep (materials); CREEP PROPERTIES; Cu-to-Cu direct bonding; DIFFUSION; Diffusivity; Lead (metal); Planes; Preferred orientation; SOLDERING ALLOYS; Solders; Surface diffusion; Creep; Diffusion; Cu-to-Cu direct bonding; Preferred orientation

We achieve low-temperature Cu-to-Cu direct bonding using highly (111)-orientated Cu films. The bonding temperature can be lowered to 200°C at a stress of 114psi for 30min at 10−3torr. The temperature is lower than the reflow temperature of 250°C for Pb-free solders. Our breakthrough is based on the...