"Copper is the most important conductor in semiconductor industry. This technology enhanced the electrical and mechanical properties of electroplating copper by using <111> nanotwinned copper. This is an essential material for the next generation copper joints. This can be applied in two major joints:
1. Low thermal budget/ low resistance copper bonding, which will be the ultra-high packaging technology for next generation high performance computing devices and stacking of high bandwidth memory.
2. High strength/ High ductility copper lines in 3D-IC packagingWe are able to fabricate highly (111) oriented nanotwinned copper films. Cu-Cu bonding can be achieved at 150°C for 1 hour under a vacuum pressure of 10-3 torr.
Nanotwinned structure has the ability to prevent dislocation under deformation, with the tensile strength reaching 2-3 times higher than regular copper.Low temp Cu-Cu bonding appears to be the solution for next generation ultra-fine pitch packaging. Nanotwinned Cu lines can also be used as redistribution lines in 3D IC integration. This technology has drawn attention from TSMC, MediaTek, Applied Materials, LAM Research, and we have projects with them to co-developed some applications. In addition, this technology also drawn attention from Apple INC from US. We are establishing collaboration with Apple through a project."