Keynote Lectures

Future Prospect for Semiconductor Technologies Supporting Automotive "Intelligence" and "Electrification"
Kiminori Hamada

Toyota Motor

Automobile development is entering two major turning points, “intelligence” and “electrification.” The former is automatic driving support technologies using AI and IoT technique toward the autonomous driving. And the latter is environmentally friendly technologies using electrified power trains such as PHV, EV and FCV.
A dramatic evolution of semiconductor technologies is indispensable to realize them. New devices such as semiconductor-laser radar, neuro chip, high-performance computing processor have been proposed and developed for automatic driving support technology. In addition, it is important to improve the performance of power semiconductor devices which are key components for further promotion of electrification.
In order to reduce the loss of IGBT which is widely used for electrified power trains, it is expected to introduce new power semiconductor devices using SiC and GaN materials, and the practical on-vehicle application has just started.
In this paper, we discuss expectations for these new electronic devices and issues for practical application.

Challenges and Opportunities in Gen3 Embedded Cooling with High Quality Microgap Flow
Avram Bar-Cohen
Gen3, Embedded Cooling, promises to revolutionize thermal management of advanced microelectronic systems by eliminating the sequential conductive and interfacial thermal resistances which dominate the present “remote cooling” paradigm. Single-phase interchip microfluidic flow with high thermal conductivity chips and substrates has been used successfully to cool single transistors dissipating more than 40kW/cm2. But efficient heat removal from transistor arrays, larger chips, and chip stacks operating at these prodigious heat fluxes would require the use of high-quality, two-phase cooling in inter- and inter-chip microgap channels. The motivation, as well as the challenges and opportunities, associated with evaporative embedded cooling is the focus of this presentation.
The lecture will begin with a brief review of the history of thermal packaging, reflecting the 70-year “inward migration” of cooling technology from the computer-room, to the rack, and then to the single chip and multichip module with attached air- and liquid-cooled coldplates. Discussion of the limitations of this approach and recent results from single=phase embedded cooling, the emerging Gen 3 thermal management paradigm, will follow.  This will set the stage for a more complete discussion of two-phase thermofluid characteristics of chip-scale microgap channels. Attention will be devoted to the effects of channel length, orientation, and gravitational, as well as centrifugal, acceleration on the prevailing flow regimes. The growth of interfacial waves and the stability of the liquid-vapor interface in Annular flow will also be discussed. The lecture will close with a description of the research needed to prepare high-quality embedded cooling for commercial application.

A New Neurofeedback Based Cognitive Training with Ultra-small NIRs System
Ryuta Kawashima
Tohoku University
Centering in advanced countries, the importance of handling cognition-related issues and demands for well-being is expanding globally. The issues with especially high needs include: (1) maintenance and enhancement of cognitive functions against aging, (2) alleviating and reducing risks for health problems related to lifestyles, and (3) achieving subjective well-being and better stress management. Neurofeedback (NF), a technique to train people to control their own brain activity into better directions, is still on a laboratory stage but will be able to provide strong supports for managing these issues.
Various training programs, cognitive or psychological therapies, and strategies have been developed and tested aiming at enhancement of cognitive functions, improvement of mental disorders and unhealthy lifestyles, and physical rehabilitation. These cognitive methods have been expected for their utility especially in fields where medication and other invasive treatments have little effect or are difficult/costly to adopt. However, difficulty of recognizing “whether using one’s own cognition properly or not” often limits the efficacy of these cognitive methods. The NF enables directly addressing this issue, with the help of recent technological advances in functional brain measurements.
In NF, one receives real-time information on his/her neural activities measured using some functional brain imaging technique while conducting specific cognitive tasks, and trains oneself to self-regulate the activities. Acquisition of voluntary modulation of a specific brain region or a network is expected to lead to improvement of the cognitive, emotional, perceptual, and motor function associated with the region/network. NF is similar to brain-computer interface (BCI) and brain-machine interface (BMI) in regard to its use of real-time neural measurement, but is unique in aiming at the volitional self-control and its resultant beneficial effects. I will introduce our NF-based cognitive training which monitors the prefrontal brain activity reflecting the user’s cognitive involvement in the training tasks using newly developed ultra-small NIRS, and leads the user to the maintenance of high PFC activity level, by switching the task types and difficulties in real-time.

Magnetism and Superconductivity
Kazuyoshi Yoshimura
Kyoto University
In these several decades, a lot of important theoretical and experimental approaches have been performed for understanding the itinerant-electron magnetism and superconductivity. Among them epoch-making was the great success of the spin-fluctuation theory for weak itinerant ferro- and antiferromagnets based on the self-consistent renormalization of spin fluctuations to magnetic free energy since 1973 (the SCR theory), exceeding the Stoner mean field theory and the dynamical mean field theory, called the random phase approximation (RPA) theory. Afterwards, the spin fluctuation theory has been developed toward the unified theory between the weakly itinerant ferro- and antiferromagnetic regime and the localized moment regime in metallic magnets by a phenomenological method. Furthermore, the itinerant-electron theory of spin fluctuations has been developed and rearranged in a quantitative way as well as by utilizing different approaches, by which we can compare the experiments and spin-fluctuation theories quantitatively by means of a set of spin-fluctuation parameters [1].
Meanwhile the novel superconductors have been discovered in the strongly correlated electron systems, such as heavy-fermion compounds and intermetallics, the organic compounds, the high-Tc cuprates, pyrochlore compounds, Co oxides with triangular lattices, Fe pnictides, and so on. Therefore, the correlations and interplays between the itinerant magnetism and the novel superconductivity, called exotic superconductivity, have been one of the most important problems in the solid-state sciences. The formalism of the BCS mean field theory should be valid even in high-Tc cuprate and iron pnictide superconductors, as well as in other strongly correlated electron superconductors, although the mediation mechanism of Cooper pairs should be different from that of BCS theory. In high-Tc cuprates, microscopic experiments have shown that the magnetic excitations were crucial, leading to the possible mechanism involving magnetic interaction-mediated Cooper pairs. In the spin-fluctuation theory, furthermore, the superconducting transition temperatures Tc of these exotic superconductors have been found to scale universally by the characteristic temperature corresponding to the energy width of spin fluctuations, T0, in exotic superconductors [1].
In this talk, the recent developments of experiments and theories in itinerant-electron magnetism and exotic superconductivity will be introduced and explained, and the future progresses as well as their applications will be discussed though in the author’s personal views.
[1] Kazuyoshi Yoshimura, J. Phys.: Conf. Series 868, 012001/1-8 (2017), and references therein.

Current Status and Trends of IC Packaging in China
Tianchun Ye
Institute of Microelectronics Chinese Academy of Sciences
With the rapid increase of global consumer markets, it is required that the electronics products should have features and characteristics such as high performance, multi-function, high reliability, miniaturation, small thickness, and low cost that make them applicable. To meet these requirements, electronics packaging technologies should provide better solutions such as lighter, thinner, denser packages with better electrical and thermal performance, higher reliability, and cost-effective. All these results are from the development and breakthrough in microelectronics packaging technology.   The initial state of electronics packaging technology in China was relatively weak. However, with Chinese intellectuals effort, and with the supports from Chinese government and State Major Project, Chinese electronics technologies have made substantial progress twenty years afterwards. Compared to international advancement, the gaps in new packaging technologies such as SiP, TSV interposer, 3D IC, WLCSP, FOWLP become narrower, while fundamental researches has led and supported the electronics packaging industry. In recent 10 years, Chinese semiconductor packaging and testing industries have made considerable progresses in terms of capacity, scale, and the strength. The capabilities of research and development in technology have been closer to those of international advancement. Some essential equipment and materials have been utilized by domestic and international production lines. Numerous Chinese companies have emerged and now been very competitive to those of international enterprises. The “Link up” phenomenon of Chinese electronics industry has been visible. The golden age for Chinese packaging and testing industry has come.