Special CMSM Seminar No.313

Abstract: The Nanomechatronics Laboratory, whose director is Prof. Namazu, explores “Mechano-Nanofunctonics”, a mechanics-based approach to create novel functions from nano- to microscale structures using mechanical stimuli and responses. By directly probing the mechanical responses of nanomaterials and architected particles and actively using mechanical stimuli to trigger and control thermal, electrical, optical, and chemical functions, we aim to design and develop new functional materials and devices for sensing, energy conversion, and advanced systems. For example, nanolayered metallic films made of a light metal and a transition metal, such as Al/Ni, show self-propagating exothermic reactions when subjected not only to an electric spark but also to a mechanical stimulus. When these shocks are applied, the film ignites, forms intermetallic compounds, and generates heat. It can ignite other portions; thus, the exothermic reaction can self-propagate through the film at around 10 m/s. The two-metal combination, atomic ratio, bilayer thickness, and total film thickness can control the exothermic characteristics. Al/Ni exothermic films are used as heat sources to melt solder for semiconductor wafer bonding [1]. The reaction requires very little external energy and produces no emissions, making it an eco-friendly semiconductor packaging technology.
This presentation will first introduce Al/Ni exothermic films and their application in semiconductor packaging. Itwill also cover nano/micromechanics topics, such as single-walled carbon nanotube mechanical characterization [2], and introduce advanced experimental mechanics technologies newly designed and developed in the laboratory.

References
[1] K. Maekawa, et al., Influence of bonded area size on cracking in reacted NiAl layer for crack-free reactive soldering, Jpn. J. Appl. Phys., 59, SIIL01, 2020.
[2] A. Takakura, et al., Strength of Carbon Nanotubes Depends on Their Chemical Structures, Nature Com., 10, 3040, 2019.

Ken-ichi Uchida
Research Center for Magnetic and Spintronic Materials
・E-mail