|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Advanced Microelectronic Packaging, Emerging Interconnection Technology, and Pb-free Solder
||Cu-to-Cu Direct Bonding by <111>-oriented Nanotwinned Copper Films with Chemical-mechanical Polishing
||Shih-Yang Chang, Chih Chen
|On-Site Speaker (Planned)
Direct Cu-to-Cu joints are desired for high performance devices to meet the demand for ultra-high I/O density. However, in the literature, the interface of two bonded Cu films or pads is usually remained as grain boundary after direct bonding process, or even after post-annealing. We reported that the direct-current electroplated (111)-oriented nanotwinned Cu (nt-Cu) exhibited extremely large grain. The as-fabricated films were chemical-mechanical Polished to lower the film roughness under 5 nm. The bonding temperatures were 250 and 300 oC for 15 to 60 min. The bonding process was in vacuum environment under about 1x10^-3 torr in a quartz furnace tube. When the bonding temperature was at 250oC, two nt-Cu can be bonded in 15 min. As the bonding time prolonged to 60 min, nt-Cu structure is still stable. However, the extremely large grain growth happened as the bonding time extended to 120 min.
||Planned: Supplemental Proceedings volume