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News Article | August 30, 2016
Site: www.nanotech-now.com

Abstract: A research team led by Professor Keon Jae Lee from the Korea Advanced Institute of Science and Technology (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) For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


This schematic image shows the flexible silicon NAND flash memory produced by the simultaneous roll-transfer and interconnection process. Credit: KAIST A research team led by Professor Keon Jae Lee from the Korea Advanced Institute of Science and Technology (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) More information: Do Hyun Kim et al, Simultaneous Roll Transfer and Interconnection of Flexible Silicon NAND Flash Memory, Advanced Materials (2016). DOI: 10.1002/adma.201602339


Kim K.-J.,Chungnam National University | Han J.-B.,Chungnam National University | Han H.-S.,KIMM | Yang S.-J.,Chungnam National University
Vehicle System Dynamics | Year: 2015

Dynamic instability, that is, resonance, may occur on an electromagnetic suspension-type Maglev that runs over the elevated guideway, particularly at very low speeds, due to the flexibility of the guideway. An analysis of the dynamic interaction between the vehicle and guideway is required at the design stage to investigate such instability, setting slender guideway in design direction for reducing construction costs. In addition, it is essential to design an effective control algorithm to solve the problem of instability. In this article, a more detailed model for the dynamic interaction of vehicle/guideway is proposed. The proposed model incorporates a 3D full vehicle model based on virtual prototyping, flexible guideway by a modal superposition method and levitation electromagnets including feedback controller into an integrated model. By applying the proposed model to an urban Maglev vehicle newly developed for commercial application, an analysis of the instability phenomenon and an investigation of air gap control performance are carried out through a simulation. © 2015 Taylor & Francis.


Jeong I.H.,University of Seoul | Jeong I.H.,Defense Agency for Technology and Quality | Jung D.H.,University of Seoul | Shin K.S.,University of Seoul | And 2 more authors.
Electronic Materials Letters | Year: 2013

The electrical characteristics and thermal shock properties of a Through Silicon Via (TSV) for the three dimensional (3D) stacking of a Si wafer were investigated. The TSVs were fabricated on a Si wafer by a laser drilling process. The via had a diameter of 75 μm at the via opening and a depth of 150 μm. A daisy chain was made for testing electrical characteristics, such as Rsh (sheet resistance), Rc (contact resistance) and Z 0 (characteristic impedance). After Cu filling, a cross section of the via was observed by Field Emission-Scanning Electron Microscopy. The electrical characteristics were measured using a commercial impedance analyzer and probe station, which revealed the values of Rsh, Rc and Z 0 as 35.5 mΩ/sq, 25.4 mΩ and 48.5 Ω, respectively. After a thermal shock test of 500 cycles, no cracks were observed between the TSV and Si wafer. This study confirms that the laser drilling process is an effective method for via formation on a Si wafer for 3D integration technology. © 2013 The Korean Institute of Metals and Materials and Springer Science+Business Media Dordrecht.


News Article | March 28, 2016
Site: www.greencarcongress.com

« California ARB posts discussion document on $500M FY 2016-17 spend for low carbon transportation and fuels; $230M to fund CVRP | Main | New DARPA Grand Challenge to focus on wireless spectrum collaboration; first collaborative machine-learning competition » Business Korea reports that a team at Korea Institute of Machinery & Materials (KIMM) has developed a Euro-6 compliant HCNG engine for intracity buses as part of a larger project consortium headed by Korea Gas Corporation (Kogas). HCNG is blend of hydrogen and compressed natural gas (CNG). Earlier studies by Kogas showed that as the hydrogen mixing volume increases, the flammable lean limit of the blended fuel expands and the combustion rate is increased. Reduced ignition delay is expected to result in increased efficiency. The lean limit expansion and the rapid combustion result in a lower combustion temperature, resulting in NO reduction. The higher the hydrogen blend rate, the lower the NO . The HCNG engine uses high EGR, and emits 18% less CO with 8% higher fuel efficiency than the CNG engine with the same output. The researchers reduced all criteria pollutant emissions to one third of the current Euro 6 emission standards; the new engine is expected to fulfill the next-generation of emission standards. Currently, the research team is test operating the HCNG engine in two intra-city buses in Ulsan and Incheon.


Min B.-K.,Hanyang University | Park C.-H.,KIMM | Chung S.-C.,Hanyang University
Proceedings - ASPE 2011 Annual Meeting | Year: 2011

A nut stiffness model including thermal effect is proposed to develop an accurate stiffness model of a ballscrew system. Differential temperature distribution is estimated through the finite difference method (FDM). The differential growth is applied for obtaining the stiffness according to assembly and load conditions.


Min B.-K.,Hanyang University | Kim M.,Hanyang University | Park C.-H.,KIMM | Chung S.-C.,Hanyang University
Proceedings - ASPE 2012 Annual Meeting | Year: 2012

Thermal nut stiffness model of a ballscrew system is proposed through accurate thermal deformation analysis. Differential temperature distribution is estimated through the finite difference method (FDM). Preload change is computed through interference analysis between shaft and nut sections. Thermal nut stiffness is estimated according to assembly, load and heat transfer conditions.


Chung S.-C.,Hanyang University | Park C.-H.,KIMM
Proceedings - ASPE 2011 Annual Meeting | Year: 2011

To verify previously developed nut stiffness model of a ballscrew, an experimental setup measuring the axial deformation and the stiffness of a ballscrew has been devised. Single-nut and double-nut ballscrews are tested under several load and assembly conditions. It is confirmed that experimental values are around 80% of the mathematical nut stiffness.


Chung S.-C.,Hanyang University | Park C.-H.,KIMM
Proceedings - ASPE 2010 Annual Meeting | Year: 2010

Positioning error of ballscrew driven feeddrives depends upon stiffness of leadscrew systems. Total axial stiffness of the leadscrew system consists of stiffnesses of the nut, the screw shaft, the support bearings, and the nut bracket. The nut stiffness depends upon screw characteristics, preload and operating conditions. This should be thoroughly studied according to the contact deformation between balls and grooves. In this paper, ballscrew nut stiffness due to contact deformation between balls and grooves according to the preload and operating conditions is studied. Positioning accuracy estimation method is also proposed.


Kim Y.,KIMM
International Journal of Advanced Robotic Systems | Year: 2015

This paper proposes a new robot controller for motor-system rehabilitation. The proposed controller simultaneously realizes rehabilitation motion tracking and force generation, as predefined through a musculoskeletal model-based optimization process. We introduce control parameters of weighted control action priorities for the motion-tracking and force-generation tasks, based on the position-tracking error. With the weighted control action priorities, the robot accords higher priority to motion tracking at the robot end point when the position-tracking error is larger than a threshold value, and to force generation when the position-tracking error is smaller than a threshold value. Smooth motion trajectory has to be designed and applied in robot-based rehabilitation. Through simulations and experimental results, we show the usefulness of the proposed control method. © 2015 Author(s). Licensee InTech.

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