Prof. Takahiro Namazu
Kyoto University of Advanced Science, Japan
Speech Title: Next-generation Instantaneous Semiconductor Die Attach Technology using Exothermic Reactive Multilayer Films
Abstract: We are now in an era where we can fabricate submicron to nano-sized mechanical structures with high precision, thanking to great progress of semiconductor fabrication technology. As material researchers, it is academically interesting that when materials are reduced to submicron-nanometer sizes, new phenomena and functions that were not seen at bulk size can emerge. For example, the plastic deformation behavior of single crystal silicon, which was only observed at approximately 600°C or higher, can be observed at around room temperature on a nanometer scale. This “size effect” of material properties is of course a subject of academic interest, and sometimes has the potential to explore new industries.
Instantaneous reactive bonding technology using metallic multilayer films can be said to be an application example that utilizes the size effect of material characteristics. This uses a metallic multilayer film that exhibits a self-propagating exothermic reaction as a heat source, and is attracting attention as an energy-saving and eco-friendly semiconductor die attach technology. A metal multilayer film, in which light metals and transition metals, such as Al/Ni, are alternately deposited to a thickness on the order of nanometers (a few nm to a few tens of nm), instantly forms intermetallic compounds and generates heat when a small external stimulus is applied (e.g., electrical, mechanical, or optical). The heat generation performance of the functional material is determined by the combination of the two metals, their atomic ratio, and bilayer thickness, which can be artificially controlled. The authors have developed a new die attach technology using an Al/Ni multilayer film, where it can be used as a local heat source to melt a solder in less than 0.1 seconds. That means, die attach assemblies for power semiconductors can be complete within 0.1 seconds. In addition, since it does not require a reflow process, it is energy-saving, highly efficient, and zero-emission bonding technology. If the bonding technologies for all the semiconductor devices can be replaced with our instantaneous bonding technology using Al/Ni exothermic reaction, and if this can be realized on a global scale, it has the potential to contribute to improving global environmental problems.
In this presentation, the exothermic performances of the Al/Ni multilayer films will be introduced. Then, the instantaneous die attach technology for Si wafers will be introduced. I will discuss on how to suppress voids and cracks introduced into the bonded section to improve the mechanical and thermal reliability of the die attach assemblies using Al/Ni multilayer films.
Biography: Takahiro Namazu received the B.S., M.S., and Ph.D. degrees in mechanical engineering from Ritsumeikan University, Kusatsu, Japan, in 1997, 1999, and 2002, respectively. From 2002 to 2006, he was an Assistant Professor with the Department of Mechanical and Systems Engineering, Graduate School of Engineering, the University of Hyogo, Himeji, Japan. In 2007, he became an Associate Professor at the university. In 2010, he joined the Precursory Research for Embryonic Science and Technology (PRESTO) program, “Nanosystems and Emergent Functions” of the Japan Science and Technology Agency (JST), as a Researcher. In the JST PRESTO program, his research project was the emergence of self-propagating exothermic nanomaterials for future semiconductor industry and human life care. In 2016, he became a Professor of the Department of Mechanical Engineering, Aichi Institute of Technology, Toyota, Japan. In 2019, he joined the Kyoto University of Advanced Science (KUAS), Kyoto, Japan, as a Visiting Professor. In 2020, he became a Professor with the Faculty of Engineering, KUAS. He is currently engaged in studies on functional film materials, such as self-propagating exothermic materials, and their applications to micro/nano electro-mechanical systems (NMEMS). His research interests also include the development of material testing techniques for measuring the mechanical properties of micro/nanoscale materials, such as carbon nanotubes and silicon nanowires, which focuses on clarifying the nanomaterials’ size effect phenomena and these mechanisms. The evaluation of the reliability of MEMS and semiconductor devices is included as well in his interests for realizing the design of ultra-long life microdevices.
Dr. Namazu has earned over 20 research awards for his outstanding materials research results and his contributions to the evolution of the micro/nanoscale materials science field in the world.
Prof. Shoichiro YOSHIHARA
Shibaura Institute of Technology, Japan
Speech Title: Recent Trends in Studies
on Corrosion Mechanisms of Magnesium Alloys for Biomedical Applications
Abstract: Magnesium is a bio-essential element, and its
application to medical devices as a bioabsorbable metallic material is
promising. For example, when plaque accumulates in blood vessels, blood
flow is reduced and a stent is applied. If a magnesium alloy can be used
as a stent, the burden on the patient can be greatly reduced because the
magnesium would dissolve away after healing. However, magnesium corrodes
very fast, and many studies have been conducted to inhibit the corrosion
rate and to clarify the corrosion mechanism of magnesium alloys. In this
keynote, the trend of magnesium will be explained with its background.
Biography: Shoichiro YOSHIHARA received his M.S. and Ph.D. degrees from Tokyo Metropolitan University, Japan, in 1995 and 1998, respectively. In 1998, he joined the National Institute of Technology, Tokyo College, Japan. In 2002, he joined the School of Mechanical and Manufacturing Engineering as Visiting Researcher, Dublin City University, Ireland. In 2005, he moved to the Graduate Faculty of interdisciplinary Research of Engineering, University of Yamanashi, Japan. In 2018, he moved to Shibaura Institute of Technology as a professor. He has been engaged in research on Metal forming and Bio-material, Nano-forming, and so forth.
Prof. Kwang Leong Choy
Duke Kunshan University, China
Speech Title: Empowering Sustainability: The Role of Advanced Materials
Abstract: This presentation highlights the development of advanced materials, particularly multifunctional nanostructured materials, for various functional applications. These include clean energy generation and storage, as well as the creation of durable materials that extend their lifespan and reduce maintenance needs. Additionally, eco-friendly and low-temperature material processes that minimize resource utilization and reduce carbon footprint, waste, and environmental impact will also be presented. This includes non-vacuum, eco-friendly aerosol-assisted chemical vapor deposition-based methods for the fabrication of sustainable thin films, which allow for more efficient use of material precursors and reduce energy consumption. The use of these eco-friendly processes to create high-value, sustainable coated components with well-controlled structures and compositions at the molecular level, applicable in engineering, renewable energy, and healthcare, will be discussed.
Biography: Kwang Leong Choy’s research focuses on the development of high performance nanostructured and nanocomposite materials based on superthin/thin/thick films using novel and advanced materials synthesis methods for solar cells, energy storage, optoelectronics, environment, engineering, healthcare and biomedical applications. Her pioneering research on the innovative, eco-friendly and cost effective non-vacuum Chemical Vapour Deposition platform technology has led to patents, technology translation and exploitation by industrial companies as well as recognition awards, including the Kroll Medal & Prize (2020) and Grunfeld Memorial Award and Medal (1999) by The Institute of Materials, Minerals and Mining (IoM3). She has led and participated in many national, European and international research projects with a large consortium of academia and industries.
She has authored four books, “Chemical Vapour Deposition (CVD): Advances, Technology and Applications” (CRC Press, 2019), “Biomaterials in Clinical Practice: Advances in Clinical Research and Medical Devices” (Springer, 2017), “Commercialization of Nanotechnologies–A Case Study Approach” (Springer, 2017) and “Innovative and Cost-effective Materials Processing Methods” (Imperial College Press, London 2002). She has over 300 publications to her name, including papers published in leading academic journals such as Progress in Materials Science, Advanced Materials and ACS Nano. Her teaching interests at Duke Kunshan include materials science, materials synthesis and characterization, nanoscale functional materials and courses that connect materials to energy, environmental science and global health sectors.
Choy has a D.Phil. in materials science from the University of Oxford and a D.Sc. in materials from the University of Nottingham. Before joining Duke Kunshan, she was the founding director of the Institute for Materials Discovery and professor for materials discovery at University College London (UCL). She was also course director of the postgraduate taught programme (MSc) in advanced materials science at UCL.
She has served as a chairperson in materials and research director of the University Innovation Centre at the University of Nottingham, and as a reader at Imperial College London. Choy also held the Violette and Glasstone Research Fellowship at the University of Oxford. She has received teaching awards from the University of Nottingham and University College London. She has been awarded Fellow of The Institute of Materials, Minerals and Mining (FIMMM) and Fellow of the Royal Society of Chemistry (FRSC) in 2007 and 2010, respectively.