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Mechanical Engineering Building on Campus Refurbished
KAIST’s Mechanical Engineering Department has finished the project to remodel its buildings and hosted an opening ceremony on December 12, 2016, which was attended by the university’s senior management and guests including President Steve Kang and Choong-Hwan Ahn, Architecture Policy Officer at the Ministry of Land, Infrastructure and Transport of Korea (MLIT).
With an investment of approximately USD 10 million, the old buildings (each consisting of seven floors and one basement) were transformed into smart, green buildings. Among the upgrades were the establishment of LED lighting systems, the replacement of the exterior walls with insulated materials, and the installation of double-glazed windows, all resulting in the improvement of the buildings’ energy efficiency. Previously, offices and lecture halls in the buildings had individual cooling and heating systems, which consumed a great deal of energy, but they were replaced with a centralized smart energy control system that monitors the operation status as well as energy consumption in real time.
With these new improvements, the Department was able to slash its energy consumption by 32%, for which it received Green Building Conversion Certification from MLIT. The ministry issues the certification to buildings that reduce their energy consumption by over 20% as a result of infrastructure upgrades. Beginning with the Mechanical Engineering buildings, KAIST will work on obtaining this certification for all of its buildings that are either under renovation or construction.
President Kang said, “We are pleased to offer our students a comfortable environment for study and research and will continue improving outdated facilities and infrastructure to make the campus safer and nicer.”
Picture 1: Ribbon-cutting ceremony for the refurbished Mechanical Engineering buildings on campus
Picture 2: Mechanical engineering buildings
2016.12.09 View 7078 -
A KAIST Team Wins the Chem-E-Car Competition 2016
A KAIST team consisted of four students from the Department of Chemical and Biomolecular Engineering won the Chem-E-Car Competition 2016, which took place on November 13 at the Union Square in San Francisco. The students who participated were Young-Hyun Cha, Jin-Sol Shin, Dae-Seok Oh, and Wan-Tae Kim. Their adviser was Professor Doh Chang Lee of the same department.
Established in 1999, the Chem-E-Car is an annual worldwide college competition for students majoring in chemical engineering. The American Institute of Chemical Engineers (AIChE), founded in 1908, is the world’s leading organization for chemical engineering professionals with more than 50,000 members from over 100 countries and hosts this competition every year.
A total of 41 university teams including Carnegie Mellon University and Purdue University participated in this year’s competition.
KAIST students competed in the event for the first time in 2014 and reached the rank of 28. In 2015, the students placed 16th, and finally, took the first place in last month’s competition, followed by the Georgia Institute of Technology.
In the competition, students must design small-scale (20x30x40 cm) automobiles that operate chemically, as well as describe their research and drive their car a fixed distance down a wedge-shaped course to demonstrate the car’s capabilities. In addition to driving a specified distance (15-30 meters), the car must hold a payload of 0-500 mL of water.
The organizers tell participants the exact distance and amount of payloads one hour before the competition begins. Winners are chosen based on their finishing time and how close their car reaches the finish line. Thus, students must show sophisticated coordination of chemical reactions to win.
The KAIST team designed their car to have a stable power output using a Vanadium redox flow battery developed by Professor Hee Tak Kim of Chemical and Biomolecular Engineering. They employed iodine clock reactions to induce quick and precise chemical reactions to control their car.
KAIST’s car finished with the best run coming within 11 cm of the target line; Georgia Tech’s car reached the finish line by 13 cm and New Jersey Institute of Technology’s car by 14 cm.
Young-Hyun Cha, one of the four students, said, “When we first designed our car, we had to deal with many issues such as stalls or connection errors. We kept working on fixing these problems through trial and error, which eventually led us to success.”
For a news article on KAIST’s win at 2016 Chemi-E-Car Competition by AIChE, see the link below:
http://www.aiche.org/chenected/2016/11/koreas-kaist-wins-1st-place-2016-chem-e-car-competition-photos
2016.12.08 View 10660 -
Professor Kwon to Represent the Asia-Pacific Region of the IEEE RAS
Professor Dong-Soon Kwon of the Mechanical Engineering Department at KAIST has been reappointed to the Administrative Committee of the Institute of Electrical and Electronics Engineers (IEEE) Robotics and Automation Society (IEEE RAS). Beginning January 1, 2017, he will serve his second three-year term, which will end in 2019. In 2014, he was the first Korean appointed to the committee, representing the Asia-Pacific community of the IEEE Society.
Professor Kwon said, “I feel thankful but, at the same time, it is a great responsibility to serve the Asian research community within the Society. I hope I can contribute to the development of robotics engineering in the region and in Korea as well.”
Consisted of 18 elected members, the administrative committee manages the major activities of IEEE RAS including hosting its annual flagship meeting, the International Conference on Robotics and Automation.
The IEEE RAS fosters the advancement in the theory and practice of robotics and automation engineering and facilitates the exchange of scientific and technological knowledge that supports the maintenance of high professional standards among its members.
2016.12.06 View 9638 -
Mystery of Biological Plastic Synthesis Machinery Unveiled
Plastics and other polymers are used every day. These polymers are mostly made from fossil resources by refining petrochemicals. On the other hand, many microorganisms naturally synthesize polyesters known as polyhydroxyalkanoates (PHAs) as distinct granules inside cells.
PHAs are a family of microbial polyesters that have attracted much attention as biodegradable and biocompatible plastics and elastomers that can substitute petrochemical counterparts. There have been numerous papers and patents on gene cloning and metabolic engineering of PHA biosynthetic machineries, biochemical studies, and production of PHAs; simple Google search with “polyhydroxyalkanoates” yielded returns of 223,000 document pages. PHAs have always been considered amazing examples of biological polymer synthesis. It is astounding to see PHAs of 500 kDa to sometimes as high as 10,000 kDa can be synthesized in vivo by PHA synthase, the key polymerizing enzyme in PHA biosynthesis. They have attracted great interest in determining the crystal structure of PHA synthase over the last 30 years, but unfortunately without success. Thus, the characteristics and molecular mechanisms of PHA synthase were under a dark veil.
In two papers published back-to-back in Biotechnology Journal online on November 30, 2016, a Korean research team led by Professor Kyung-Jin Kim at Kyungpook National University and Distinguished Professor Sang Yup Lee at the Korea Advanced Institute of Science and Technology (KAIST) described the crystal structure of PHA synthase from Ralstonia eutropha, the best studied bacterium for PHA production, and reported the structural basis for the detailed molecular mechanisms of PHA biosynthesis. The crystal structure has been deposited to Protein Data Bank in February 2016. After deciphering the crystal structure of the catalytic domain of PHA synthase, in addition to other structural studies on whole enzyme and related proteins, the research team also performed experiments to elucidate the mechanisms of the enzyme reaction, validating detailed structures, enzyme engineering, and also N-terminal domain studies among others.
Through several biochemical studies based on crystal structure, the authors show that PHA synthase exists as a dimer and is divided into two distinct domains, the N-terminal domain (RePhaC1ND) and the C-terminal domain (RePhaC1CD). The RePhaC1CD catalyzes the polymerization reaction via a non-processive ping-pong mechanism using a Cys-His-Asp catalytic triad. The two catalytic sites of the RePhaC1CD dimer are positioned 33.4 Å apart, suggesting that the polymerization reaction occurs independently at each site. This study also presents the structure-based mechanisms for substrate specificities of various PHA synthases from different classes.
Professor Sang Yup Lee, who has worked on this topic for more than 20 years, said,
“The results and information presented in these two papers have long been awaited not only in the PHA community, but also metabolic engineering, bacteriology/microbiology, and in general biological sciences communities. The structural information on PHA synthase together with the recently deciphered reaction mechanisms will be valuable for understanding the detailed mechanisms of biosynthesizing this important energy/redox storage material, and also for the rational engineering of PHA synthases to produce designer bioplastics from various monomers more efficiently.”
Indeed, these two papers published in Biotechnology Journal finally reveal the 30-year mystery of machinery of biological polyester synthesis, and will serve as the essential compass in creating designer and more efficient bioplastic machineries.
References:
Jieun Kim, Yeo-Jin Kim, So Young Choi, Sang Yup Lee and Kyung-Jin Kim. “Crystal structure of Ralstonia eutropha polyhydroxyalkanoate synthase C-terminal domain and reaction mechanisms” Biotechnology Journal DOI: 10.1002/biot.201600648
http://onlinelibrary.wiley.com/doi/10.1002/biot.201600648/abstract
Yeo-Jin Kim, So Young Choi, Jieun Kim, Kyeong Sik Jin, Sang Yup Lee and Kyung-Jin Kim. “Structure and function of the N-terminal domain of Ralstonia eutropha polyhydroxyalkanoate synthase, and the proposed structure and mechanisms of the whole enzyme” Biotechnology Journal DOI: 10.1002/biot.201600649
http://onlinelibrary.wiley.com/doi/10.1002/biot.201600649/abstract
2016.12.02 View 10053 -
Aerospace Engineering Students Win the Minister's Award
On November 11, 2016, students from KAIST’s Aerospace Engineering Department won the Minister’s Award of Trade, Industry and Energy of Korea at the 14th Research Paper Competition hosted by Korea Aerospace Industries (KAI). The award came with a cash prize of USD 1,200 as well as opportunities to visit international airshows held abroad.
The KAIST students' paper introduced a novel design concept for "a virtual-fighter-pilot system for unmanned combat aerial vehicles to enable them to engage in mass aerial combat."
This was one of the two highest honors given to contestants. A group of students from Korea Aerospace University received the other grand prize from the Minister of Land, Infrastructure and Transport of Korea.
The KAIST team consisted of two doctoral students, Hee-Min Shin and Jae-Hyun Lee, and one Master’s student, Hyun-Gi Kim. Their advisor, Professor “David” Hyunchul Shim, received the Special Achievement Award for his contribution to the paper.
KAI’s competition was established in 2003 to spur academic interest and research in aerospace engineering. Over the past 14 years, contestants have submitted 376 papers, and KAI has published 88 papers. KAI has positioned itself as the host of one of the most prestigious research paper competitions held in Korea in the area of aerospace engineering.
The Korean Society for Aeronautical and Space Sciences, the Korea Aerospace Industries Association, and the Korea Civil Aviation Development Association also sponsored the competition, with the Ministries of Trade, Industry and Energy and of Land, Infrastructure and Transport.
Professor Shim said, “This represents a great honor for our students. In recent years, research in unmanned aerial systems has increased tremendously throughout the world, and I hope KAIST will continue to inspire and innovate research in this field.”
Pictured from left to right are Hee-Min Shin, Jae-Hyun Lee, and Hyun-Gi Kim.
Pictured from right to left are Professor Hyunchul Shim, Hyun-Gi Kim, Hee-Min Shin, and Vice President Sung-Sup Chang of Korea Aerospace Industries.
2016.11.22 View 11515 -
KAIST's Doctoral Student Receives a Hoffman Scholarship Award
Hyo-Sun Lee, a doctoral student at the Graduate School of EEWS (Environment, Energy, Water and Sustainability), KAIST, is a recipient of the 2016 Dorothy M. and Earl S. Hoffman Scholarships presented by the American Vacuum Society (AVS). The award ceremony took place during the Society’s 63rd International Symposium and Exhibition on November 6-11, 2016 in Nashville, Tennessee.
Lee is the first Korean and foreign student to receive this scholarship.
The Hoffman Scholarships were established in 2002 to recognize and encourage excellence in graduate studies in the sciences and technologies of interest to AVS. The scholarships are funded by a bequest from Dorothy M. Hoffman, who was a pioneering member of the Society of Women Engineers and served as the president of AVS in 1974.
Lee received the scholarship for her research that detects hot electrons from chemical reactions on catalytic surface using nanodevices. Nano Letters, an academic journal published by the American Chemical Society, described her work in its February 2016 issue as a technology that allows quantitative analysis of hot electrons by employing a new nanodevice and therefore helps researchers understand better the mechanism of chemical reactions on nanocatalytic surface. She also published her work to detect the flow of hot electrons that occur on metal nanocatalytic surface during hydrogen oxidation reactions in Angewandte Chemie.
Lee said, “I am pleased to receive this honor from such a world-renowned academic society. Certainly, this will be a great support for my future study and research.”
Founded in 1953, AVS is an interdisciplinary, professional society composed of approximately 4,500 members worldwide. It supports networking among academic, industrial, government, and consulting professionals involved in a range of established and emerging science and technology areas such as chemistry, physics, engineering, business, and technology development.
2016.11.17 View 9558 -
Key Interaction between the Circadian Clock and Cancer Identified
Professor Jae Kyoung Kim and his research team from the Department of Mathematical Sciences at KAIST found that the circadian clock drives changes in circadian rhythms of p53 which functions as a tumor suppressor. Using a differential equation, he applied a model-driven mathematical approach to learn the mechanism and role of p53.
Kim’s mathematical modeling has been validated by experimental studies conducted by a research team at Virginia Polytechnic Institute and State University (Virginia Tech) in the United State, which is led by Professor Carla Finkielstein. As a result, the researchers revealed that there is an important link existed between the circadian clock and cancer.
The findings of this research were published online in Proceedings of the National Academy of Sciences of the United States of the America (PNAS) on November 9, 2016.
The circadian clock in our brain controls behavioral and physiological processes within a period of 24 hours, including making us fall asleep at a certain time by triggering the release of the sleep hormone melatonin in our brain, for example, around 9 pm. The clock is also involved in various physiological processes such as cell division, movement, and development.
Disruptions caused by the mismatch of the circadian clock and real time due to chronic late night work, shiftwork, and other similar issues may lead to various diseases such as diabetes, cancer, and heart disease.
In 2014, when Kim met with Finkielstein, her research team succeeded in observing the changes of p53 over a period of 24 hours, but could not understand how the circadian clock controls the 24-hour rhythm of p53. It was difficult to determine p53’s mechanism since its cell regulation system is far more complex than other cells
To solve the problem, Kim set up a computer simulation using mathematical modeling and ran millions of simulations. Instead of the traditional method based on trial and error experiments, mathematical modeling allowed to save a great deal of time, cost, and manpower.
During this process, Kim proved that the biorhythm of p53 and Period2, an important protein in the circadian clock, are closely related. Cells usually consist of a cell nucleus and cytoplasm. While p53 exists in both nucleus and cytoplasm, it becomes more stable and its degradation slows down when it is in the nucleus.
Kim predicted that the Period2 protein, which plays a key role in the functioning of the circadian clock, could influence the nucleus entry of the p53 protein.
Kim’s predictions based on mathematical modeling have been validated by the Virginia team, thereby revealing a strong connection between the circadian clock and cancer.
Researchers said that this research will help explain the cause of different results from numerous anticancer drugs, which are used to normalize the level of p53, when they are administrated at different times and find the most effective dosing times for the drugs.
They also believe that this study will play an important role in identifying the cause of increasing cancer rates in shift-workers whose circadian clocks are unstable and will contribute to the development of more effective treatments for cancer.
Professor Kim said, “This is an exciting thing that my research can contribute to improving the healthy lives of nurses, police officers, firefighters, and the like, who work in shifts against their circadian rhythms. Taking these findings as an opportunity, I hope to see more active interchanges of ideas between biological sciences and mathematical science in Korea.”
This research has been jointly conducted between KAIST and Virginia Tech and supported by the T. J. Park Science Fellowship of POSCO, the National Science Foundation of the United States, and the Young Researcher Program of the National Research Foundation of Korea.
Picture 1. The complex interaction between tumor antigen p53 and Period2 (Per2) which plays a major role in the circadian clock as revealed by mathematical simulations and experiments
Picture 2. A portion of the mathematical model used in the research
Picture 3. Professor Jae Kyoung Kim (third from left) and the Virginia Tech Research Team
2016.11.17 View 7637 -
Professor Lee Co-chairs the Global Future Councils on Biotechnology of the WEF
The World Economic Forum (WEF) established a new global network of the world’s leading experts, “The Annual Meeting of the Global Future Councils,” to explore innovative solutions for the most pressing global challenges. The Councils’ first meeting took place on November 13-14, 2016, in Dubai, the United Arab Emirates (UAE). Some 25 nations joined as member states. The Councils have 35 committees.
Over 700 global leaders in business, government, civil society and academia gathered at the inaugural meeting to “develop ideas and strategies to prepare the world for the Fourth Industrial Revolution, with topics including smart cities, robotics, and the future of mobility,” according to a statement issued by the WEF.
Distinguished Professor Sang Yup Lee of Chemical and Biomolecular Engineering at KAIST was appointed to co-chair one of the Councils' committees, The Annual Meeting of the Global Future Councils on Biotechnology, for two years. The other chairperson is Dr. Feng Zhang, a professor of Biomedical Engineering at the Massachusetts Institute of Technology (MIT), who played a critical role in the development of optogenetics and CRISPR technologies.
The Biotechnology Committee consists of 24 globally recognized professionals in life sciences, law, ethics and policy including Thomas Connelly, the executive director of the American Chemical Society, Tina Fano, the executive vice president of Novozymes, and Mostafa Ronaghi, the chief technology officer of Illumina.
Professor Lee also serves as a committee member of The Annual Meeting of the Global Future Councils on the Fourth Industrial Revolution.
“Life sciences and engineering will receive more attention as a key element of the Fourth Industrial Revolution that the global society as a whole has been experiencing now. Together with thought leaders gathered worldwide, I will join the international community’s concerted efforts to address issues of importance that impact greatly on the future of humanity,” Professor Lee said.
In addition, Professor Lee received the James E. Bailey Award 2016 from The Society for Biological Engineering on November 15, 2016. He is the first Asian researcher to be recognized for his contributions to the field of biotechnology.
2016.11.15 View 9188 -
MOU between KAIST and DTU Signed
KAIST and the Technical University of Denmark (DTU) signed a memorandum of understanding (MOU) to cooperate in the areas of startup, student exchange, and joint research on October 25, 2016 at the Embassy of Denmark in Seoul, Korea. Under the agreement, KAIST and DTU will exchange students and researchers through startup programs and continue to collaborating in education and research.
The MOU was facilitated during the Green Growth Alliance Meeting and Energy Seminar hosted by the Danish embassy, in which Danish Prime Minister Lars Løkke Rasmussen participated.
President Steve Kang of KAIST, who fostered the agreement, said,
“DTU has been one of our strategic partners in Europe. We have been working closely with them on academic exchanges and research collaborations, but now with the expansion of our cooperation into entrepreneurship, we will create momentum to spur startups in both schools. To support such activities, we will use KAIST’s experiences acquired from operating the K-School, an entrepreneurship graduate school, and the Institute of KAIST Entrepreneurship. DTU will also share their knowledge on startup programs including SkyLab and StartDTU. I believe this will become another successful alliance between the two universities.”
As of October 2016, KAIST has made 18 agreements with DTU, exchanging 120 students in the past three years and implementing various joint seminars and conferences for academic and research exchanges.
Established in 1829, DTU has been a leading science and technology university in Denmark. It ranked 109 in the QS World University Rankings 2016 and 46th in its subject rankings in engineering and technology.
In the picture below, President Steve Kang of KAIST (right) and Senior Vice President Martin P. Bendsøe of the Technical University of Denmark (left) are signing an agreement for academic and research cooperation.
2016.10.27 View 7928 -
2016 KAIST EEWS Workshop
The Energy, Environment, Water and Sustainability (EEWS) Graduate School of KAIST hosted a workshop entitled “Progress and Perspectives of Energy Science and Technology” on October 20, 2016. The workshop took place at the Fusion Hall of the KAIST Institute on campus.
About 400 experts in energy science and engineering participated in the event. Eight globally recognized scientists introduced the latest research trends in nanomaterials, energy theory, catalysts, and photocatalysts and led discussions on the current status and prospects of EEWS.
Professors Yi Cui of Stanford University, an expert in nanomaterials, and William A. Goddard of California Institute of Technology presented their research experiments on materials design and recent results on the direction of theory under the topics of energy and environment.
Dr. Miquel Salmeron, a former head of the Material Science Division of Lawrence Berkeley National Laboratory, and Professor Yuichi Ikuhara of Tokyo University introduced their analysis of catalysts and energy matters at an atomic scale.
Professor Sukbok Chang of the Chemistry Department at KAIST, a deputy editor of ACS Catalysis and the head of the Center for Catalytic Hydrocarbon Functionalizations at the Institute of Basic Science, and Professor Yang-Kook Sun of Energy Engineering at Hanyang University, who is also a deputy editor of ACS Energy Letters, presented their latest research results on new catalytic reaction development and energy storage.
The workshop consisted of three sections which addressed the design of energy and environment materials; analysis of energy and catalytic materials; and energy conversion and catalysts.
The EEWS Graduate School was established in 2008 with the sponsorship of the Korean government’s World Class University (WCU) project to support science education in Korea. Professor J. Fraser Stoddart, the winner of the 2016 Nobel Prize in Chemistry, was previously worked at the KAIST EEWS Graduate School as a WCU visiting professor for two years, from 2011 to 2013. Professor Ali Coskun, who was a postdoctoral researcher in the laboratory of Professor Stoddart, now teaches and conducts research as a full-time professor at the graduate school.
Dean Yousung Jung of the EEWS Graduate School said:
“This workshop has provided us with a meaningful opportunity to engage in discussions on energy science and technology with world-class scholars from all around the world. It is also a good venue for our graduate school to share with them what we have been doing in research and education.”
2016.10.20 View 12531 -
Extremely Thin and Highly Flexible Graphene-Based Thermoacoustic Speakers
A joint research team led by Professors Jung-Woo Choi and Byung Jin Cho of the School of Electrical Engineering and Professor Sang Ouk Kim of the Material Science and Engineering Department, all on the faculty of the Korea Advanced Institute of Science and Technology (KAIST), has developed a simpler way to mass-produce ultra-thin graphene thermosacoustic speakers.
Their research results were published online on August 17, 2016 in a journal called Applied Materials & Interfaces. The IEEE Spectrum, a monthly magazine published by the Institute of Electrical and Electronics Engineers, reported on the research on September 9, 2016, in an article titled, “Graphene Enables Flat Speakers for Mobile Audio Systems.” The American Chemical Society also drew attention to the team’s work in its article dated September 7, 2016, “Bringing Graphene Speakers to the Mobile Market.”
Thermoacoustic speakers generate sound waves from temperature fluctuations by rapidly heating and cooling conducting materials. Unlike conventional voice-coil speakers, thermoacoustic speakers do not rely on vibrations to produce sound, and thus do not need bulky acoustic boxes to keep complicated mechanical parts for sound production. They also generate good quality sound in all directions, enabling them to be placed on any surface including curved ones without canceling out sounds generated from opposite sides.
Based on a two-step, template-free fabrication method that involved freeze-drying a solution of graphene oxide flakes and the reduction/doping of oxidized graphene to improve electrical properties, the research team produced a N-doped, three-dimensional (3D), reduced graphene oxide aerogel (N-rGOA) with a porous macroscopic structure that permitted easy modulation for many potential applications.
Using 3D graphene aerogels, the team succeeded in fabricating an array of loudspeakers that were able to withstand over 40 W input power and that showed excellent sound pressure level (SPL), comparable to those of previously reported 2D and 3D graphene loudspeakers.
Choong Sun Kim, the lead author of the research paper and a doctoral student in the School of Electrical Engineering at KAIST, said:
“Thermoacoustic speakers have a higher efficiency when conducting materials have a smaller heat capacity. Nanomaterials such as graphene are an ideal candidate for conductors, but they require a substrate to support their extremely thinness. The substrate’s tendency to lose heat lowers the speakers’ efficiency. Here, we developed 3D graphene aerogels without a substrate by using a simple two-step process. With graphene aerogels, we have fabricated an array of loudspeakers that demonstrated stable performance. This is a practical technology that will enable mass-production of thermosacoustic speakers including on mobile platforms.”
The research paper is entitled “Application of N-Doped Three-Dimensional Reduced Graphene Oxide Aerogel to Thin Film Loudspeaker.” (DOI: 10.1021/acsami.6b03618)
Figure 1: A Thermoacoustic Loudspeaker Consisted of an Array of 16 3D Graphene Aerogels
Figure 2: Two-step Fabrication Process of 3D Reduced Graphene Oxide Aerogel Using Freeze-Drying and Reduction/Doping
Figure 3: X-ray Photoelectron Spectroscopy Graph of the 3D Reduced Graphene Oxide Aerogel and Its Scanning Electron Microscope Image
2016.10.05 View 13524 -
Continuous Roll-Process Technology for Transferring and Packaging Flexible Large-Scale Integrated Circuits
A research team led by Professor Keon Jae Lee from KAIST and by Dr. Jae-Hyun Kim from the Korea Institute of Machinery and Materials (KIMM) has jointly developed a continuous roll-processing technology that transfers and packages flexible large-scale integrated circuits (LSI), the key element in constructing the computer’s brain such as CPU, on plastics to realize flexible electronics.
Professor Lee previously demonstrated the silicon-based flexible LSIs using 0.18 CMOS (complementary metal-oxide semiconductor) process in 2013 (ACS Nano, “In Vivo Silicon-based Flexible Radio Frequency Integrated Circuits Monolithically Encapsulated with Biocompatible Liquid Crystal Polymers”) and presented the work in an invited talk of 2015 International Electron Device Meeting (IEDM), the world’s premier semiconductor forum.
Highly productive roll-processing is considered a core technology for accelerating the commercialization of wearable computers using flexible LSI. However, realizing it has been a difficult challenge not only from the roll-based manufacturing perspective but also for creating roll-based packaging for the interconnection of flexible LSI with flexible displays, batteries, and other peripheral devices.
To overcome these challenges, the research team started fabricating NAND flash memories on a silicon wafer using conventional semiconductor processes, and then removed a sacrificial wafer leaving a top hundreds-nanometer-thick circuit layer. Next, they simultaneously transferred and interconnected the ultrathin device on a flexible substrate through the continuous roll-packaging technology using anisotropic conductive film (ACF). The final silicon-based flexible NAND memory successfully demonstrated stable memory operations and interconnections even under severe bending conditions. This roll-based flexible LSI technology can be potentially utilized to produce flexible application processors (AP), high-density memories, and high-speed communication devices for mass manufacture.
Professor Lee said, “Highly productive roll-process was successfully applied to flexible LSIs to continuously transfer and interconnect them onto plastics. For example, we have confirmed the reliable operation of our flexible NAND memory at the circuit level by programming and reading letters in ASCII codes. Out results may open up new opportunities to integrate silicon-based flexible LSIs on plastics with the ACF packing for roll-based manufacturing.”
Dr. Kim added, “We employed the roll-to-plate ACF packaging, which showed outstanding bonding capability for continuous roll-based transfer and excellent flexibility of interconnecting core and peripheral devices. This can be a key process to the new era of flexible computers combining the already developed flexible displays and batteries.”
The team’s results will be published on the front cover of Advanced Materials (August 31, 2016) in an article entitled “Simultaneous Roll Transfer and Interconnection of Silicon NAND Flash Memory.” (DOI: 10.1002/adma.201602339)
YouTube Link: https://www.youtube.com/watch?v=8OJjAEm27sw
Picture 1: This schematic image shows the flexible silicon NAND flash memory produced by the simultaneous roll-transfer and interconnection process.
Picture 2: The flexible silicon NAND flash memory is attached to a 7 mm diameter glass rod.
2016.09.01 View 11324