Keynote Lectures

Reinventing the Technology Roadmap
William T. Chen
ASE Group

The electronic industry has reinvented itself through multiple disruptive changes in market, business, and technologies. We are now entering a new era of digital economy with data migration to the cloud, smart devices everywhere, Internet of Things to Internet of Everything, and the emergence of autonomous vehicles. While Moore’s Law is slowing, the pace of technology innovation continues to expand to meet challenges of the new era. With the closure of ITRS by SIA (last ITRS 2.0 edition published on July 8th 2016), the crucial question is: what are the critical paths going forward? The IEEE CPMT, EDS, and Photonics Societies and SEMI have joined in collaboration to re-invent the Technology Roadmap for the professional, industry, academia and research communities. The Heterogeneous Integration Roadmap (HIR) will follow directly the purpose, process and format of the ITRS for the 15-year assessment of future requirement, and 25-year assessment for emerging materials and devices. The roadmap will address disruptive changes in the market place, major challenges in technology requirements, while identifying roadblocks and potential solutions. This talk will report on the progress of the making of the 1st edition of the Roadmap and the work of the nineteen Technical Working Groups. Such involves achieving the purpose to provide long term vision into the future and identifying the needs of future system applications. Further, it will identify the technologies at semiconductor, package, and system integration levels that will address future technology requirements. We shall provide examples in the roadmap chapters from Heterogeneous Components, Integrations Processes, Materials, and Special Applications.

Organic LEDs for Displays and Lighting
Junji Kido
Frontier Center for Organic Materials,
Yamagata University

In the past 30 years, the performance of organic LEDs (OLEDs) has been steadily improved and, today, a variety of OLED display products are in the market.  Small-size OLEDs are used for smart phones and tablets, and large-size are used for televisions.  White OLEDs are considered to be the general lighting of the next generation.  These days, high quantum efficiencies (QEs) can be obtained by using phosphorescent emitters such as iridium complexes. External QE of 25―30% was achieved for blue, green and red OLEDs, which correspond to the internal QE of nearly 100%.  Device lifetime at high luminance levels, which is required for general lighting, has been significantly improved by using the tandem structure.  By combining the above techniques, OLEDs can be extremely efficient and possess extremely long lifetime, even at high luminance level.  A white OLED with a high efficiency of 150lm/W can be obtained.  In this talk, recent progress in OLED will be discussed.

3D-Integration and Wafer Bonding for MEMS Packaging: Overview and examples
Joerg Froemel
Fraunhofer Project Center for MEMS/NEMS devices and manufacturing technologies,
Tohoku University

Academia and companies have demonstrated excellent progress in realizing amazing micro devices ranging through all aspects of our modern life. However, only a fraction of these devices have brought it to the market level. Albeit many of the non-successful micro parts had conceptual deficiencies, several very promising devices were stopped in their tracks by the sheer cost of interfacing them to the real world. Wafer level packaging as well as 3D-integration are essential technologies for successful MEMS application. An overview of current concepts will be given including actual examples and technologies, including innovative via fabrication. Furthermore, low-temperature (<400°C) bonding of semiconductor wafers is an important technology for 3D integration and other heterogeneous integration schemes. Recent progress in this technology field will be reviewed focusing on metal thermocompression bonding with gold and copper, also highlighting a development by using Ag as bonding material. Ag-Ag bonding does not require surface treatment before bonding and still can achieve high strength (>100MPa) at relatively low temperature, such as 300°C. Beside results also the underlying mechanism is explained. Another focus will be put at SLID (solid liquid interdiffusion) bonding using Au/Sn, Au/Ga and Cu/Ga. By using gallium as interface material metal-metal bonding below 100°C is possible. It will be explained and shown in detail. The bonding by Ga SLID has been investigated regarding the bonding parameters and their influence on bond interface properties. After temperature treatment of 90°C, a shear strength of up to 90 MPa and hermetic bond could be achieved. Phase transition in the solid phase from CuGa2 to Cu9Ga4 was found to be the key for an increase in bonding strength.

Converter-in-Package: Realising the Potential of Wide Band-Gap Power Electronics
C Mark Johnson
UK Engineering and Physical Sciences Research Council (EPSRC) Centre for Power Electronics

Wide band-gap semiconductors offer many potential benefits to designers of power electronic systems. Lower switching losses allow operation at higher switching frequencies, which in principle allows a reduction in passive component values in many converter applications. However, the efficient operation of WBG devices at higher switching frequencies requires increased voltage and current transition rates compared to typical Silicon devices. Currents induced through parasitic capacitances, as a result of high dv/dt and voltages induced in parasitic inductances, as a result of high di/dt, can both be expected to be higher with WBG devices. Regrettably, Silicon power module technology is far from ideal in this regard. Firstly, the typical buss bar/screw terminal or solder/spring pin interconnect adds significant inductance to the commutation loop formed with the external decoupling capacitor. The resulting transient voltage spikes and ringing will add to the electromagnetic interference (EMI) emitted from the system. Secondly, the typical design of power module substrate results in a relatively high capacitance from the switching node to the module baseplate and hence to ground if, as is typical, the module is mounted on a grounded, metal heatsink. This can lead to unacceptable levels of common mode current flow. Alternative designs, incorporating low-inductance interconnects, integrated passives and effective screening of common mode currents are desirable. Outside the commutation cell, fast voltage transitions may lead to unacceptably high levels of conducted and radiated EMI, so approaches involving the local filtering of converter outputs are attractive. If these are incorporated into the commutation cell there is the potential to deliver integrated solutions that confine the EMI within the converter commutation cell. Here we examine the design and realisation of “Converter-in-Package” (CiP) modular blocks for system power levels up to 100s kW, incorporating individual commutation cells with close-coupled gate drives, input/output filtering and electromagnetic screening/shielding.