• 한국레이저가공학회지
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• 제6권2호
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• pp.35-41
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• 2003

In this study, manufacturing of polymer master and mold insert for micro injection molding was investigated. Ablation by excimer laser radiation could be used successfully to make 3-D microstructure of PET. The mechanism for ablative decomposition of PET with KrF excimer laser(λ: 248nm, pulse duration: 5ns) was explained by photochemical process. And this process showed PET to be adopted in polymer master for nickel mold insert. Nickel electroforming by using laser ablated PET master was preferable for replication method. Finally, it was shown that excimer laser ablation can substitute for X-ray lithography of LIGA process in microstructuring.

• 마이크로전자및패키징학회지
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• 제30권2호
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• pp.65-70
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• 2023

나노임프린트 리소그래피(Nanoimprint lithography, NIL) 공정은 패턴 형성을 위한 공정 단순성, 우수한 패턴 형성, 공정의 확장성, 높은 생산성 및 저렴한 공정 비용이라는 이유들로 인해 많은 관심을 받고 있다. 그러나, 기존의 NIL 기술들을 통해 금속 소재 상 구현할 수 있는 패턴의 크기는 일반적으로 마이크로 수준으로 제한적이다. 본 연구에서는, 다양한 두께의 금속 기판 표면에 마이크로/나노 스케일 패턴을 직접적으로 형성하기 위한 극압 임프린트 리소그래피(extremepressure imprint lithography, EPIL) 방법을 소개하고자 한다. EPIL 공정은 자외선, 레이저, 임프린트 레지스트 또는 전기적 펄스 등의 외부 요인을 사용하지 않고 고분자, 금속, 세라믹과 같은 다양한 재료의 표면에 신뢰성 있는 나노 수준의 패터닝을 가능하게 한다. 레이저 미세가공 및 포토리소그래피로 제작된 마이크로/나노 몰드는 상온에서 높은 하중 혹은 압력을 가해 정밀한 소성변형 기반 Al 기판의 나노 패터닝에 활용된다. 20 ㎛ 부터 100 ㎛까지 다양한 두께를 갖는 Al 기판 상 마이크로/나노 스케일의 패턴 형성을 보여주고자 한다. 또한, 다목적 EPIL 기술을 통해 금속 재료 표면에서 그 형상을 제어하는 방법 역시 실험적으로 증명된다. 임프린트 리소그래피 기반 본 접근법은 복잡한 형상이 포함된 금속 재료의 표면을 요구하는 다양한 소자 응용을 위한 나노 제조 방법에 적용될 수 있을 것으로 기대한다.

• 한국광학회:학술대회논문집
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• 한국광학회 1991년도 제6회 파동 및 레이저 학술발표회 Prodeedings of 6th Conference on Waves and Lasers
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• pp.81-87
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• 1991

A design of a four-mirror optical system for submicron lithography using KrF excimer laser beam(λ=248nm) is presented. By using the third order aberration theory, analytic solutions for a telecentric, flat-field, and anastigmatic four-spherical-mirror system (reduction magnification 5$\times$) are found. Aspherization is carried out to the spherical mirror surfaces in order to reduce the residual higher order aberrations and vignetting effect. Finally we obtain a reflection system useful in submicron lithographic application.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.440-444
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• 1995

StereoLithography는 3차원 CAD로 작성된 모델데이타를 이용하여입체조형 실물을 빠르게 제작 하는 Rapid Prototype 기술의 한 방식으로서, 감광성 수지를 자외선 Laser 광에 의해 선택적으 로 경회시켜 원하는 한 단면형상을 이룬후 적층하는 반복작업에 의해 입체 형상을 조형하는 기법 이다. Rapid Prototype 시스템은 제품개발기간 단축과 설계완성도를 높이는 목적으로 최근 산업계에서 그 활용도가 점차 증가하는 추세에 있으며, 3차원 CAD 시스템과 함께 제품개발 체제를 통합화하고 Concurrent Engineering의 실현을 위한 주요한 Tool로써 자리를 잡아가고 있다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.78-78
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• 1999

Experimental studies of laser micromachining on Mo metal using piezo Q-switched Nd:YAG laser have been performed. Miniaturized microcolumn electron gun arrays as a potential electron beam lithography or portable mini-scanning electron microscope application have recently extensively examined. For these purpose, the electro-static electron lens and deflector system called microcolumn has to be assembled. The conventional microcolumn fabrication technique would gave a limitation on the minimization of aberration. The current technique of a 1 $\mu$m misalignment would lead to ~1.3 nm coma. In order to reduce aberration, assembling the microcolumn component followed by laser drilling should be very beneficial. In this report, we will address the preliminary report of laser micromachining on Mo substrate using piezo Q-switched Nd:YAG laser. The geometrical figures, such as the diameter and the depth of the frilled aperture are dependent upon the total energy of the laser pulse train, laser pulsewidth, and the diameter of laser beam in addition to the materials-dependent parameters.

• 한국진공학회지
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• 제8권4A호
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• pp.456-460
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• 1999

Experimental studies of laser micromachining on Mo diaphragm using piezo Q-switched Nd:YAZ laser have been performed. Application of miniaturized micorcolumn electron gun arrays as a potential electron beam lithography or portable mini-scanning electron microscope (SEM) application have recently extensively examined. The conventional microcolumn fabrication technique would give a limitation on the minimization of aberration, In this paper, we obtained 20~30 $\mu \textrm m$aperture of laser micromachining on Mo diaphragm using piezo Q-swithed Nd:YAG laser. The geometrical figures, such as the diameter and the preciseness of the drilled aperture are dependent upon the total energy of the laser pulse train, laser pulse width, and the diameter of laser spot in addition to the materials-dependent parameters.

• 한국레이저가공학회지
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• 제10권2호
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• pp.5-15
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• 2007

A new printing process for LCD color filter is proposed in this work by using the localized laser heating, which is called laser-induced spray printing (LISP) process. The LISP is a non-contact process, which injects the ink from the donor substrate to the glass substrate by the bubble pressure induced by laser heating. The temperature distribution of the donor substrate is calculated numerically to explain the ink ejection phenomena. The composition of the ink was includes the red pigment, n-butanol, xylene, BCA and epoxy. Experiments were conducted by using the fiber laser system, and the color filter patterns were deposited successfully under the proper laser heating conditions.

• Journal of the Optical Society of Korea
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• 제9권1호
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• pp.16-21
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• 2005

Using a cantilever type nanoprobe having a 100㎚m aperture at the apex of the pyramidal tip of a near-field scanning optical microscope (NSOM), nanopatterning of polymer films are conducted. Two different types of polymer, namely a positive photoresist (DPR-i5500) and an azopolymer (Poly disperse orange-3), spincoated on a silicon wafer are used as the substrate. A He-Cd laser with a wavelength of 442㎚ is employed as the illumination source. The optical near-field produced at the tip of the nanoprobe induces a photochemical reaction on the irradiated region, leading to the fabrication of nanostructures below the diffraction limit of the laser light. By controlling the process parameters properly, nanopatterns as small as 100㎚ are produced on both the photoresist and azopolymer samples. The shape and size variations of the nanopatterns are examined with respect to the key process parameters such as laser beam power, irradiation time or scanning speed of the probe, operation modes of the NSOM (DC and AC modes), etc. The characteristic features during the fabrication of ordered structures such as dot or line arrays using NSOM lithography are investigated. Not only the direct writing of nano array structures on the polymer films but also the fabrication of NSOM-written patterns on the silicon substrate were investigated by introducing a passivation layer over the silicon surface. Possible application of thereby developed NSOM lithography technology to the fabrication of data storage is discussed.

• ETRI Journal
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• 제24권5호
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• pp.341-348
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• 2002

We propose an asymmetric sampled grating laser and a multi-wavelength laser array associated with it. Asymmetric sampling periods combined with an index shifter make it possible to use first order reflection for lasing operations. With the structure of our design, we achieved a simple fabrication procedure as well as a high yield without using complex and time-consuming e-beam lithography for multi-period gratings. We analyzed the effect of mirror coating by numerical analysis to improve single mode and power extraction performance. By using high reflection-antireflection coatings, we obtained high power extraction efficiency without degradation of the single mode property. For the multi-wavelength laser array, to gain wavelength control, we varied the sampling periods from one laser to an adjacent laser across the array. With this approach, we showed the feasibility of an array of up to 30 channels with 100 GHz wavelength spacing.

• 전자공학회논문지D
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• 제34D권12호
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• pp.62-67
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• 1997

The optical lithography wit an ArF excimer laser as a light source is expected to be used in the mass production of giga-bit DRAMs which require less than 0.2.mu.m minimum feature size. In this case, the distortion of a patterned image becomes very severe, since the lithography porcess is performed at the resolution limit. Traditionally, the photomask pattern was designed and revised with trial-and-error methods, such as repeated execution of process simulators or actual process experiments which require time and effort. Ths paper describes a program which automatically finds an optimal mask pattern. The program divides the mask plane into cells with same sizes, chooses a cell randomly, changes the transparent/opaque property of the cell, and eventually genrates a mask pattern which produces required image pattern. The program was applied to real DRAM cell patterns to produce mask patterns which genertes image patterns closer to object images than original mask patterns.