• Laser Solutions
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• v.3 no.3
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• pp.13-19
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• 2000

The stencil is a thin stainless sheet in which a pattern is formed, which is placed on a surface of plate to reproduce the pattern of electric circuit. Conventionally the stencil has been produced by etching process. This process has many anti-environmental factors. In this study, Nd : YAG laser cutting process has been applied for stencil manufacturing. The study is focused on estimating kerf width of laser cut stencil by E.B.P.(Error Back-Propagation). This algorithm is good for estimating target value from input value. In this paper, target value was kerf width, and input values were frequency, pulse width, cutting speed and laser power. E.B.P. after teaming input and target could estimate kerf width from some variables precisely.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.644-647
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• 2001

Amorphous As-Ge-Se-S thin films have been studied with the aim of identifying optimum etching condition which can be used to produce holographic grating structure for use as diffractive optical elements. In this study, holographic gratings have been formed using He-Ne laser(632.8nm), and fabricated by the method of wet etching using NaOH etchant with various concentration(0.26N, 0.33N, 0.40N). The diffraction efficiency was obtained by +1st order intensity of the diffracted beam. The formed grating profiles were observed by atomic force microscope and showed that the expected grating profile could be achieved by controlling the etching time. Over-etching resulted in under-cutting of the grating lines. The highest 1st order diffraction efficiency for these gratings was about 5.05%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.12
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• pp.1271-1276
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• 2004

Two-dimensionally arrayed nanocolumn lattices were fabricated by using double-exposure laser holographic method. The hexagonal lattice was formed by rotating the sample with 60 degree while the square lattice by 90 degree before the second laser-exposure. The reactive ion etching for a typical time of 30 min using CH$_4$/H$_2$ plasma enhanced the aspect-ratio by more than 1.5 with a slight increase of the bottom width of columns. The etch-damage was observed by photoluminescence (PL) spectroscopy which was removed by the wet chemical etching using HBr/$H_2O$$_2$/$H_2O$ solution, leading into the enhanced PL intensities of the PCs.

• Design & Manufacturing
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• v.2 no.4
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• pp.1-4
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• 2008

Micro pattern is applied to the light guiding plate(LGP) to enhance the uniformity of the brightness of the LCD. The micro cones are molded in intaglio on the surface of the LGP. The surface roughness of each cone was 40nm and 38nm in negative and positive die for laser ablation. In chemical etching, the surface roughness was 25nm, 24nm in negative and positive. And the surface roughness of negative and positive dies were 4nm and 5nm for LIGA-reflow process.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1430-1431
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• 2006

We investigated the formation of 2-dimension hologram grating by means of selective etching characteristic and photo-expansion effect according to photo irradiation on amorphous As-Ge-Se-S thin film. By method of phase holography, we made the 2-dimensional hologram grating by each (S:P) and ($+45^{\circ}:-45^{\circ}$) polarized beam with DPSS laser(532nm) and He-Ne laser(632nm). A recording property was observed at each polarized beam through 2-dimensional hologram surface relief grating. Chalcogenide thin film was etched selectively by NaOH solution after the formation of 1-dimensional diffraction grating. And then etched sample was rotated 90 degree to fabricate 2 dimensional hologram grating. We found that it was observed the formation of 2-dimensional hologram grating by AFM(Atomic Force Microscopy).

• 전기의세계
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• v.34 no.8
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• pp.470-475
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• 1985

우주물질의 대부분이 플라즈마 상태에 있지마는 지구상에서는 천둥이 칠 때 생기는 방전이나 극지방에서 볼 수 있는 오로라와 같이 극히 일부분이 자연상태의 프라즈마로 존재한다. 지금까지 플라즈마의 이용은 그것이 내는 밝은 빛을 이용한 조명이나, 높은 열을 이용한 용접이나 절단이 고작이었으나, 최근에 들어 초고온, 고밀도 플라즈마를 이용한 핵융합 에너지 연구나 Free Electron Laser나 Gyrotron과 같이 새로운 Radiation Source로써 종래의 Source가 만들지 못하던 주파수 영역이나 Glow Discharge에서 생기는 저온 Plasma를 이용한 Plasma Etching PECVD(Plasma Enhanced CHemical Vapor Deposition), Plasma Ashing, Sputtering등은 VLSI의 제조에 필요불가결한 공정의 일부분이 되고 있다. 앞으로 수회에 걸쳐 본 기술해설란을 통하여 이들 Plasma의 이용 기술을 소개하고자 하며 본회에서는 그중에서 Plasma Etching에 대해서 그 원리와 기술상의 특징을 살펴보고자 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.353-354
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• 2012

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.78-79
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• 2007

• Laser Solutions
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• v.3 no.2
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• pp.45-51
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• 2000

In this paper, the possibilities and the limits of the laser seam welding were studied to utilize the advantageous properties of amorphous metal foils. For the conventional welding method, the high heat transfer makes the crystallized zone of the work material unavoidable. The laser is able to weld the amorphous metal without a crystallized zone, because heat transfer is limited within a very small restricted volume. The crystallized zone is restricted in the neighbor of welding spot and not in the melting area. This can be proved directly by the etching and indirectly by the tensile shear test, micro hardness test and bending test. The overlapping of welding bead could form the formation of wider and thicker amorphous zone.

• Laser Solutions
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• v.14 no.2
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• pp.13-16
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• 2011

We fabricated the Fresnel zone plate using femtosecond laser lithography-assisted micro-machining, which is a combined process of nonlinear lithography and wet etching. We investigated the focusing properties by launching a 632.8nm wavelength He-Ne laser beam into the zone plate. The spot size of the primary focal point was $27{\mu}m$ and the intensity of focal point was 0.565W/$cm^2$.