• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1203-1206
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• 2004

마이크로 컬럼은 차세대 리소그라피 기술의 하나로 마이크로 컬럼의 기능이 기존의 전자빔 컬럼을 능가하여 주목을 받는다. 초소형 전자빔 컬럼은 기존의 전자빔 컬럼과 비교하여 수차, 렌즈의 크기 및 원형에 성능이 보다 민감하게 반응하므로 정확한 정렬과 가공 기술은 초소형 전자빔 마이크로 컬럼의 성능에 매우 중요하다. 그러나, 기준치 piezoelectric transducer (PZT)나 scanning tunneling microscopy (STM)을 이용한 정렬 기술은 매우 복잡하고 어려운 단점이 있다. 본 연구에시는 레이저 회절 패턴방식과 레이저 정밀 가공으로 실리콘 렌즈와 파이렉스 spacer를 정확하게 교대로 조립하였으며, 이 방법으로 완성된 마이크로 컬럼의 STEM동작을 조사하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.62-62
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• 2010

Photonic quasi-crystals(PQCs) have been fabricated by a multiple-exposure nanosphere lithography (MENSL) method using the self-assembled nanospheres as lens-mask patterns. The multiple-exposing source is collimated laser beam and rotation, tilting system. The arrays of the PQCs exhibited variable lattice structures and shape the control of ratating angle ($\theta$), tilting angle ($\gamma$) and the exposure conditions. The used nanosphere size is upto the $1\;{\mu}m$. Images of prepared 2D PQCs were observed by SEM. We believe that the MENSL method is a suitable useful tool to realize the PQCs arrays of large area.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.3
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• pp.472-477
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• 2003

A piezo-actuator is an important component for an E-beam lithography system. But it is very difficult to model its characteristics due to nonlinearities such as hysteresis and creep, to the input voltage. In this paper, one-axis micro stage with a piezo-actuator is modeled including the nonlinear properties. Hysteresis and creep are modeled as the first order differential equation and a time-dependent logarithmic function, respectively. The dynamic motion of the stage is also modeled as a mass-spring-damper system and the parameters are determined by utilizing the system identification technique. The simulation tool for a micro stage is constructed using the commercial software and its simulation results are compared with the experimental data.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1078-1082
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• 2003

A feasibility study for the fabrication of master replication with nanostructures by Nanoimprint Lithography (NIL) was investigated for application of polymer Photonic Bandgap (PBG) devices used in photonic IC. Large area gratings of $9{\times}15(mm^2)$ with p = 400 nm was successfully embossed on PMMA on silicon wafer and the embossing parameters (temperature, pressure, time) were established. A precise control of $O_2$ plasma Reactive Ion Etching (RIE) process time allowed window opening over the whole area despite the presence of wafer bending. Master replication with aspect ratio 1 was successfully fabricated, but master replication with aspect ratio 3 needs to optimize parameters. All replications were done in a NIL process.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1065-1068
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• 2003

The nano imprint process is one of the next generation lithography has been mentioned as one of major nanoreplication techniques because it is simple process, low cost, high replication fidelity and relatively high throughput. This process requires a surface contact between a template with patterns and a wafer on a stage. After contact, the vertical moving the template to the wafer causes some directional motions of the stage. Thus the stage must move according to the motions of the template to avoid the damage of the transferred patterns on the wafer. This study is to develop the wafer stage with a passive compliance to overcome the damage. This stage is designed with the concept like that it has a monolithic, symmetry and planar 6-DOF mechanism.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.2
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• pp.245-250
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• 2011

A high-resolution shadow mask, a nanostencil, is widely used for high resolution lithography. This high-resolution shadowmask is often fabricated by a combination of MEMS processes and focused ion beam (FIB) milling. In this study, FIB milling on 500-nm-thin SiN membrane was tested and characterized. 500 nm thick and $2{\times}2$ mm large membranes were made on a silicon wafer by micro-fabrication processes of LPCVD, photolithography, ICP etching and bulk silicon etching. A subsequent FIB milling enabled local membrane thinning and aperture making into the thinned silicon nitride membrane. Due to the high resolution of the FIB milling process, nanoscale apertures down to 60 nm could be made into the membrane. The nanostencil could be used for nanoscale patterning by local deposition through the apertures.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.2
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• pp.236-240
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• 2013

In this presentation, we propose a fabrication method of PDMS stencil to apply into a localized culture of NIH/3T3 cells. PDMS stencil was fabricated by nitrogen gas blowing and soft lithography from preparing SU-8 master mold by photolithography. PDMS stencil pattern was production of the circle size 20 to $500{\mu}m$. In the culture test of PDMS stencil, a stencil was placed on a glass disk. The NIH/3T3 cells were successfully cultured into micropatterns by using the PDMS stencil. The results showed that cells could be cultured into micropatterns with precisely controlled manner at any shapes and specific size for bioscience study and bioengineering applications.

• Proceedings of the Optical Society of Korea Conference
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• 1998.08a
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• pp.192-193
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• 1998

At Rutherford Appleton Laboratory(RAL), a high-repetition rate ps exicmer laser-plasma x-ray source has been developed for x-ray lithography with a calibrated output of up to 1 watt X-ray average power at 1nm wavelength. In a previous reports this compact x-ray source was used to print 0.18$\mu$m lines for a gate on Si-FET devices and deep three-dimensional structure with 100$\mu$m length, 25$\mu$m width, and 48 $\mu$m depth for a nanotechnology. The deep X-ray lithography is called as LIGA thchnology and getting a wide interest as a new technology for a nano-device. In this report all this works are summarized.

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.199-200
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• 2007

UV 처리 광학 접착제를 가지고 단일 포토리소그라피 공정을 사용하여 마이크로 렌즈를 제작하였다. 먼저 유리판 위에 자외선 처리 광학 접착제를 코팅 한 후 UV 노광하고 아세톤에서 현상 후 핫플레이트에서 유리전이 온도 이상에서 열적 재흐름이 일어나도록 하여 마이크로 렌즈를 만드는데 성공하였다 이를 실제 LED 소자 위에서 마이크로 렌즈를 만들어 보고 LED의 외부 추출 효율이 높아지는지를 실험하였다. 또한 기존의 UV 처리 광학 접착제에 나노 입자을 첨가하여 굴절률을 더 높여 마이크로 렌즈를 만드는 실험을 하였다.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.6
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• pp.36-40
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• 2009

Development of maskless lithography techniques can provide a potential solution for the photomask cost issue. Furthermore, it could open a market for small scale manufacturing applications. Since femtosecond lasers have been found suitable for processing of a wide range of materials with sub-micrometer resolution, it is attractive to use this technique for maskless lithography. As a femtosecond laser has recently been developed, both of high power and high photon density are easily obtained. The high photon density results in photopolymerization of photoresist whose absorption spectrum is shorter than that of the femtosecond laser. The maskless lithography using the two-photon absorption (TPA) makes micro structures. In this paper, we present a femtosecond laser direct write lithography for submicron PR patterning, which show great potential for future application.