Papers by Author: Seung Woo Lee

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Authors: Seung Woo Han, Ki Jeong Seo, Jae Jong Lee, Seung Woo Lee, Hak Joo Lee, Jung Yup Kim
Abstract: Nanoimprint lithography is a promising technology to produce sub-100 nm scale features on silicon chips. One of key issues in the nanoimprint lithography is how to make uniform contact between the stamp and the substrate on a large area. In this study a rubber membrane unit under substrate is introduced to resolve this problem. Two layers of membrane were designed to consider air flow in the middle of resist on a silicon wafer. The geometry design for accomplishing uniform contact was carried out using finite element analysis. The material modeling of hyperelastic properties of rubber is characterized by the Mooney-Rivlin strain energy functions. Material constants in the strain energy functions are able to be determined via the curve fitting of experimental stress-strain data. Simple tension and equi-biaxial tests were performed to determine the material constants. To evaluate the effects of a rubber membrane unit, nanoimprint lithography process with it was executed. We could confirm that a distinct improvement of uniform contact was shown and air flow problem was solved during the process.
Authors: Seung Woo Lee, Seung Woo Han, Jun Yeob Song, Wan Doo Kim, Hwa Ki Lee
Abstract: The reliability, that is long-term quality, requires a different approaching from short-term quality which is used before. As the electronic components are to be easily normalized on the reliability evaluation, many reliability prediction methodologies are used. In this study, integrated reference model of reliability prediction is serviced for existing PRISM and Bellcore which is related on reliability prediction about electronic components, and will service reliability data based on PoF (Physics of Failure) from domestic research center. The constructed frame of reliability evaluation system, which can predict and evaluate reliability of electronic components and MEMS, is designed by using online service of the reliability data accumulated on web. To evaluate proposed system, the reliability evaluation of PCB (Printed Circuits Boards), which is used in NC controller of machine tools, is introduced according to PRISM, the representative reference model of reliability prediction about electronic components based on MIL-HDBK-217F.
Authors: Jae Jong Lee, Seung Woo Lee, Hyun Taek Cho, Gee Hong Kim, Kee Bong Choi
Abstract: The contact-based nanoimprinting lithography (NIL), such as thermal and/or UV nano-imprint, has been well known as one of the next generation lithography alternatives. Especially, the UV nanoimprinting lithography technology has the advantages in terms of process simplicity, low cost, high replication fidelity, and relatively high throughput. The UV nanoimprinting lithography tool is built with the characteristic functions like a self-alignment wafer stage, a nanoimprinting head unit, an alignment system for multi-layer process, stamp/wafer chucking units, releasing unit, and anti-vibration unit, etc. This UV-NIL tool is comprised of UV light source using mercury lamp, ultra-fine XY stage with nano-level positioning accuracy, and self-adjusting flexure stage. The self-adjusting stage has the capability to control 6- axes positions of wafer-holder. The UV-NIL tool can be used for fabrication of some functional nanostructure-patterns i.e. nanosensor electrodes, optical grating patterns and 70nm rectangle patterns.
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