Technical Name Low temperature instant copper bondinghigh toughness/low resistance RDL lines using 111 nanotwinned copper linesfoils
Project Operator National Chiao Tung University
Project Host 陳智
Electroplated nanotwinned Cu possesses excellent electrical & mechanical properties. It can be applied in three major joints:
1. Low thermal budget/ low resistance Cu bonding for high performance computing chip.
We are able to achieve low temperature bondinginstant bonding. Low temperature bonding is performed at 150°C for 1 h to achieve low contact resistance copper bonding. Instant bonding is performed at 300°C for 5 seconds under a pressure of 90MPa achieve low contact resistance.
2. High strength/ High ductility copper lines in 3D-IC packaging 
We are able to fabricate high strength foils with tensile strength of 800MPa. After annealing at 150°C for 3 hours, the foil retains a tensile strength of 750MPa. 3. Cu foils for lithium ion battery
Technical Film
Scientific Breakthrough
We are able to DC electroplate highly (111) oriented nanotwinned copper filmsfabricate high strength/high conductivity/High toughness copper lines in 3D-IC packaging 
The tensile strength can be as high as 800MPa while maintaining reasonable ductility. After annealing at 150°C for 3 hours, the foil retains a tensile strength of 750MPa. This exhibits the ideal thermal stabilitytoughness ductility for 3D-IC application. In addition, with the Cu foils, the energy density can be increased.
Industrial Applicability
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,we have projects with them to co-developed some applications. In addition, this technology also drawn attention from  the US
Matching Needs
1.Cu-Cu bonding, fine pitch, low thermal budget, low resistance junction.
2.High electromigration resistancehigh strength Cu lines.
3.high strength nanotwinned Cu.
Keyword nanotwinned copper Cu film with large grains high strength/ high thermal stability low temperature low pressure copper bondin Cu current collector for lithium ion battery Instant Cu-Cu bonding 3D IC integration AI chip packaging High electromigration resistance RDL Low resistance/ High strength Cu lines/foil
Download 2012-11 Science Unidirectional growth of microbumps in nt-Cu.pdf
2015-2 Scientific Reports Cu direct bonding by nt-Cu.pdf
2020-8 Materials Tensile strength of different nt-Cu structures_down sized.pdf
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