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24 results on '"Lee, Joong Ha"'

2. Dual mode operation of bistable chiral splay nematic liquid crystal cell using horizontal switching for dynamic operation.

Author

Lee, Seong Ryong, Lee, Joong Ha, Jhun, Chul Gyu, Kwon, Soon-Bum, Yoon, Tae-Hoon, and Kim, Jae Chang

Subjects
*LIQUID crystal displays, *OPTICAL bistability, *ELECTRIC fields, *SUBSTRATES (Materials science), *ELECTRODES
Abstract

We propose a dual mode liquid crystal display (LCD), which can realize dynamic and memory operating LCD modes in a display panel. Horizontal switching and bistable chiral splay nematic LCD modes are used for the dynamic and memory operations, respectively. As the horizontal switching is applied to the dynamic operation, it is possible to use the same LC texture of splay for realizing dark states of both the dynamic and memory operations. Because, for each operation, pixel division is not required in the proposed dual mode LCD, there is no decrease in aperture ratio and resolution. In order to obtain superior display performance for both operations, a wideband half-wave configuration is employed to the proposed dual mode LCD. Due to the wideband configuration, very low light leakages at the dark state and good dispersion characteristics for the entire visible range are obtained. As a result, the proposed dual mode LCD shows a high contrast ratio of over 100:1 for both the dynamic and memory operations. [ABSTRACT FROM AUTHOR]

Published
2009
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8. Gray scale realization in bistable chiral splay nematic liquid crystal device

Author

Jhun, Chul Gyu, primary, Chen, Ken, additional, Jin, Yan, additional, Hong, Zhe, additional, Han, Seung Hwan, additional, Zhang, Yong, additional, Seo, Ye Won, additional, Park, Ginah, additional, Kwon, Soon-Bum, additional, Shin, Sung Sik, additional, Lee, Joong Ha, additional, Yoon, Tae-Hoon, additional, Kim, Jae Chang, additional, and Chung, Suk Moon, additional

Published
2011
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24. Effects of Chamber Pressure on the Performance of CO2 Beam Cleaning

Author

Kim, Seung Ho, Lee, Joong Ha, and Kim, Ho Young

Abstract

As the size of functional patterns in the semiconductor chips shrinks down to below 100 nm, removing nanoscale contaminant particles is an important technological challenge that the current semiconductor manufacturing industry must overcome. Several cleaning methods proposed to date, such as megasonic cleaning [1], droplet impact [2], and cryogenic aerosol cleaning [3], have difficulties in cleaning of sub-100 nm contaminant particles, let alone their tendency to induce pattern damages. Kim et al. [4] has recently developed a new method, where CO2 solid particles nucleated from a supersonic nozzle physically attack contaminant nanoscale particles on the wafer, thus detaching them. A drawback of this novel scheme is that the cleaning must be executed in vacuum because CO2 gas needs to sublimate into solid and be accelerated supersonically as exiting the nozzle. This has adverse effects on the cost and rate of the semiconductor manufacturing process. Here we investigate the effects of vacuum chamber pressure on the performance of the CO2 dry cleaning system. We observe the cryogenic CO2 beams, dents induced by CO2 solid particles, and wafer surfaces initially contaminated with cerium oxide particles, which indicate the effects of the chamber pressure.

Published
2014
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