• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.591-596
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• 2006

Lead zirconate titanate(PZT) thin films have been attracting worldwide interests in exploring their potential properties [1-3] or the origins [4-6] of their excellent dielectic, ferroelectric and piezoelectric properties near the morphotropic phase boundary (MPB). PZT thin films are expected to apply to the memory devices, micro electro mechanical systems (MEMS), and display because of their superior ferroelectric, pyroelectric, piezoelectric and electron emission properties. In this study, high- performance piezoelectric PZT thin films for actuated mirror array and optical scanner were developed by controlling the several factors, such as molecular-designed precursor, seeding layer and the residual stress in films, by a chemical solution deposition (CSD).

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.39.1-39
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• 2002

We present nanoactuators and nanodetectors for high-precision Micro Electro Mechanical System (MEMS) applications. Major technical difficulties in the high-precision MEMS are arising from the fabrication uncertainty and electrical noise problems. In this paper, we present high-precision actuators and detectors, overcoming the technical limitations placed by the conventional MEMS technology. For the nano-precision actuation, we present a nonlinearly modulated digital actuator (NMDA). NMDA composed of a digital microactuator and a nonlinear micromechanical modulator. The nonlinear micromechanical modulator is intended to purify the actuation errors in the stroke of the digital a...

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.12a
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• pp.82-85
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• 2003

MEMS(Micro Electro Mechanical Systems) 응용 분야에 있어서 RF나 Optic등에 응용되는 금속 구조물이나 배선을 위한 도금, 두꺼운 구조물의 식각등을 위해서 수십 um두께의 감광막이 필요하다. 특히 이러한 감광막은 도금을 위한 전단계에서 몰드 형성에 이용되는데 그 이유는 제작이 용이할 뿐만 아니라 다양한 두께 형성이 가능하고 금속과의 선택적 제거가 쉬운 장점이 있다. 감광막 몰드가 갖추어야 할 조건으로는 수직에 가까운 측면 기울기, 두께, 도금액에 대찬 저항성을 들 수 있으며 그 중에서 측면 기울기 개선에 관한 연구가 많이 진행되고 있다. 본 논문에서는 감광막의 형상에 영향을 주는 요인을 찾아내고 수식모델링을 통해 측면 기울기를 예측하고자 한다.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.114-115
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• 2003

최근 급속히 성장하고 있는 Wavelength-division-multiplexing (WDM) 시스템에 파장가변 필터는 핵심적인 소자로 적용될 수 있으며, 높은 가격 경쟁력과 광학 필터로서 좋은 특성과 높은 가변 특성을 구현할 수 있다. 이러한 파장가변 필터는 multi-beam 간섭을 이용하고, Micro electro mechanical systems (MEMS) 공정 기술인 벌크 마이크로 머시닝 기술을 이용하여 구현되어지고 있다. 또한 파장 가변 필터는 Optical-performance monitoring, Spectrometer, Optical noise filter, Sensor 등 여러 분야에 응용될 수 있다. (중략)

• Tribology and Lubricants
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• v.33 no.6
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• pp.282-287
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• 2017

SU-8 is an epoxy-type photoresist widely used for the fabrication of high-aspect-ratio (HAR) micro-structures in micro-electro-mechanical systems (MEMS). To fabricate highly integrated structures, chemical mechanical polishing (CMP) has emerged as the preferred manufacturing process for planarizing the MEMS structure. In SU-8 CMP, an oxidizer decomposes organic impurities and particles in the CMP slurry remove the chemically reacted surface of SU-8. To fabricate HAR microstructures using the CMP process, the adhesion between SU-8 and substrate material is important to avoid the delamination of the SU-8 film caused by the mechanical-dominant material removal characteristic. In this study, the friction force during the CMP process is measured with a CMP monitoring system to detect the delamination phenomenon and investigate the delamination of the SU-8 film from the silicon substrate under various pressure conditions. The increase in applied pressure causes an increase in the frictional force and wafer-edge stress concentration. The frictional force measurement shows that the friction force changes according to the delamination phenomenon of the SU-8 film, and that it is possible to monitor the delamination phenomenon during the SU-8 CMP process. The delamination at a high applied pressure is explained by the effect of stress distribution and pad deformation. Consequently, it is necessary to control the pressure of polishing, which can avoid the delamination in SU-8 CMP.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.7
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• pp.30-36
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• 2004

Recently, the lead-time of a product is to be shortened in order to satisfy consumer's demand. It is thus important to reduce the manufacturing time and the cost of 3D-shaped microstructures. Micro-Electro-Mechanical Systems (MEMS) and devices are usually fabricated by lithography-based methods. Above method is not flexible for the rapid manufacture of 3D-shaped microstructures because it depends on work's experiences and requires excessive cost and time for making many masks. In this paper, the effective laser micrornachining is developed to fabricate UV sensitive polymer microstructures using laser ablation. The proposed process, named by laser microRP, is a very useful method on rapid manufacturing for 3D-shaped microstructures.

• Applied Microscopy
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• v.51
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• pp.8.1-8.7
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• 2021

Growing demands for comprehending complicated nano-scale phenomena in atomic resolution has attracted in-situ transmission electron microscopy (TEM) techniques for understanding their dynamics. However, simple to safe TEM sample preparation for in-situ observation has been limited. Here, we suggested the optical microscopy based micro-manipulating system for transferring TEM samples. By adopting our manipulator system, several types of samples from nano-wires to plate-like thin samples were transferred on micro-electro mechanical systems (MEMS) chip in a single step. Furthermore, the control of electrostatic force between the sample and the probe tip is found to be a key role in transferring process.

• Smart Structures and Systems
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• v.18 no.4
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• pp.787-800
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• 2016

The aim of the paper is to analyze nonlinear transverse vibration of an embedded piezoelectric plate reinforced with single walled carbon nanotubes (SWCNTs). The system in rested in a Pasternak foundation. The micro-electro-mechanical model is employed to calculate mechanical and electrical properties of nanocomposite. Using nonlinear strain-displacement relations and considering charge equation for coupling between electrical and mechanical fields, the motion equations are derived based on energy method and Hamilton's principle. These equations can't be solved analytically due to their nonlinear terms. Hence, differential quadrature method (DQM) is employed to solve the governing differential equations for the case when all four ends are clamped supported and free electrical boundary condition. The influences of the elastic medium, volume fraction and orientation angle of the SWCNTs reinforcement and aspect ratio are shown on frequency of structure. The results indicate that with increasing volume fraction of SWCNTs, the frequency increases. This study might be useful for the design and smart control of nano/micro devices such as MEMS and NEMS.

• Current Optics and Photonics
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• v.1 no.2
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• pp.143-149
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• 2017

LED arrays with pixel numbers of $3{\times}3$, $4{\times}4$, and $5{\times}5$ have been studied in this paper in order to enhance the optical output power and decrease heat dissipation of an AlGaInP-based light emitting diode display device (pixel size of $280{\times}280{\mu}m$) fabricated by micro-opto-electro-mechanical systems. Simulation results showed that the thermal resistances of the $3{\times}3$, $4{\times}4$, $5{\times}5$ arrays were $52^{\circ}C/W$, $69.7^{\circ}C/W$, and $84.3^{\circ}C/W$. The junction temperature was calculated by the peak wavelength shift method, which showed that the maximum value appears at the center pixel due to thermal crosstalk from neighboring pixels. The central temperature would be minimized with $40{\mu}m$ pixel pitch and $150{\mu}m$ substrate thickness as calculated by thermal modeling using finite element analysis. The modeling can be used to optimize parameters of highly integrated AlGaInP-based LED arrays fabricated by micro-opto-electro-mechanical systems technology.

• Journal of Advanced Navigation Technology
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• v.23 no.3
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• pp.228-236
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• 2019

Recently, multi-sensor integration techniques have been actively studied to obtain reliable and accurate navigation solution in GPS (Global Positioning System)-denied harsh environments such as urban canyons, tunnels, and underground roads. In this paper, we propose a low-cost ultrasonic-speedometer utilizing the characteristics of the ultrasonic propagation. An efficient integrated INS (inertial navigation system)/ultrasonic-speedometer navigation system is also proposed to improve the accuracy of positioning in GPS-denied environments. To evaluate the proposed system, car experiments with field-collected measurements were performed. By the experiment results, it was confirmed that the proposed INS/ultrasonic-speedometer system bounds the positioning error growth effectively even though GPS signal is blocked more than 10 seconds and a low-cost MEMS IMU (micro electro mechanical systems inertial measurement unit) is utilized.