• Title/Summary/Keyword: laser writing

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Design and Fabrication of a Micro-Heat Pipe with High-Aspect-Ratio Microchannels (고세장비 미세채널 기반의 마이크로 히트파이프 설계 및 제조)

  • Oh, Kwang-Hwan;Lee, Min-Kyu;Jeong, Sung-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.9 s.186
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    • pp.164-173
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    • 2006
  • The cooling capacity of a micro-heat pipe is mainly governed by the magnitude of capillary pressure induced in the wick structure. For microchannel wicks, a higher capillary pressure is achievable for narrower and deeper channels. In this study, a metallic micro-heat pipe adopting high-aspect-ratio microchannel wicks is fabricated. Micromachining of high-aspect-ratio microchannels is done using the laser-induced wet etching technique in which a focused laser beam irradiates the workpiece placed in a liquid etchant along a desired channel pattern. Because of the direct writing characteristic of the laser-induced wet etching method, no mask is necessary and the fabrication procedure is relatively simple. Deep microchannels of an aspect ratio close to 10 can be readily fabricated with little heat damage of the workpiece. The laser-induced wet etching process for the fabrication of high-aspect-ratio microchannels in 0.5mm thick stainless steel foil is presented in detail. The shape and size variations of microchannels with respect to the process variables, such as laser power, scanning speed, number of scans, and etchant concentration are closely examined. Also, the fabrication of a flat micro-heat pipe based on the high-aspect-ratio microchannels is demonstrated.

Formation of copper films from copper formate by laser-induced pyrolytic decomposition (Copper formate의 레이저 유도 열 분해에 의한 Cu 박막의 제조)

  • Kim, Jae-Kwon;Park, Se-Ki;Lee, Cheon
    • Proceedings of the KIEE Conference
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    • 1998.07d
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    • pp.1444-1446
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    • 1998
  • Direct writing of copper lines has been achieved by pyrolytic decomposition of copper formate films using a focused argon ion laser beam($\lambda$ =514.5nm) on a glass. The thickness and linewidth of the deposited copper films were considered as a function of laser power and scan speed. As the result from AES, there are no other elements except for copper after decomposition in the atmospheric ambient.

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Process Study of Direct Laser Lithographic System for Fabricating Diffractive Optical Elements with Various Patterns (다중 패턴의 회절광학소자 제작을 위한 레이저 직접 노광시스템의 공정 연구)

  • Kim, Young-Gwang;Rhee, Hyug-Gyo;Ghim, Young-Sik;Lee, Yun-Woo
    • Journal of the Semiconductor & Display Technology
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    • v.18 no.2
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    • pp.58-62
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    • 2019
  • Diffractive Optical Elements(DOEs) diffracts incident light using the diffraction phenomenon of light to generate a desired diffraction image. In recent years, the use of diffraction optics, which can replace existing refractive optical elements with flat plates, has been increased by implementing various optical functions that could not be implemented in refractive optical devices and by becoming miniaturized and compacted optical elements. Direct laser lithography is typically used to effectively fabrication such a diffractive optical element in a large area with a low process cost. In this study, the process conditions for fabricating patterns of diffractive optical elements in various shapes were found using direct laser lithographic system, and optical performance evaluation was performed through fabrication.

A Study of Mastless Pattern Fabrication using Stereolithography (광조형을 이용한 마스크리스 패턴형성에 관한 연구)

  • 정영대;조인호;손재혁;임용관;정해도
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.503-507
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    • 2002
  • Mask manufacturing is a high COC and COO process in developing of semiconductor devices, because of the mass production tool with high resolution. Direct writing has been thought to be one of the patterning method to cope with development or small-lot production of the device. This study focused on the development of the direct, mastless patterning process using stereolithography tool for the easy and convenient application to micro and miso scale products. Experiments are utilized by three dimensional CAD/CAM as a mask and photo-curable resin as a photo-resist in a conventional stereo-lithography apparatus. Results show that the resolution of the pattern was achieved about 300 micron because of complexity of SLA apparatus settings, inspite of 100 micro of inherent resolution. This paper concludes that photo resist and laser spot diameter should be adjusted to get finer patterns and the proposed method is significantly feasible to mastless and low cost patterning with micro and miso scale.

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The study of optimal reduced-graphene oxide line patterning by using femtosecond laser pulse (펨토초 레이저 펄스를 이용한 환원된 그래핀의 최소 선폭 패턴 구현에 관한 연구)

  • Jeong, Tae-In;Kim, Seung-Chul
    • Journal of the Korea Convergence Society
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    • v.11 no.7
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    • pp.157-162
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    • 2020
  • In recent years, laser induced graphene process have been intensively studied for eco-friendly electronic device such as flexible electronics or thin film based energy storage devices because of its simple and effective process. In order to increase the performance and efficiency of an electronic device using such a graphene patterned structure, it is essential to study an optimized laser patterning condition as small as possible linewidth while maintaining the graphene-specific 2-dimensional characteristics. In this study, we analyzed to find the optimal line pattern by using a Ti:sapphire femtosecond laser based photo-thermal reduction process. we tuned intensity and scanning speed of laser spot for generating effective graphene characteristic and minimum thermal effect. As a result, we demonstrated the reduced graphene pattern of 30㎛ in linewidth by using a focused laser beam of 18㎛ in diameter.

Phase change properties of BN doped GeSbTe films

  • Jang, Mun-Hyeong;Park, Seong-Jin;Park, Seung-Jong;Jeong, Gwang-Sik;Jo, Man-Ho
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.226-226
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    • 2010
  • Boron Nitride (BN) doped GeSbTe films were grown by the ion beam sputtering deposition (IBSD). The in-situ sheet resistance data and the x-ray diffraction patterns showed the crystallization is suppressed due to the BN incorporation. The phase change speed in BN doped GeSbTe films were investigated using the static tester equipped with nanosecond pulsed laser. The phase change speed for BN doped GST films become faster than the corresponding values for an undoped GST film. The Johnson-Mehl-Avrami(JMA) plot and Avrami coefficient for laser crystallization showed that the change in growth mode during the laser crystallization is a most important factor for the phase change speed in the BN doped GST films. The JMA results and the atomic force microscopy (AFM) images indicate that the origin of the change in the crystalline growth mode is due to an increase in the number of initial nucleation sites which is produced by the incorporated BN. In addition, the retension properties for the laser writing/erasing are remarkably improved in BN doped GeSbTe films owing to the stability of the incorporated BN.

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