• Journal of information and communication convergence engineering
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• 제3권4호
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• pp.191-194
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• 2005

SU-8 is a epoxy based photoresist designed for MEMS applications, where a thick, chemically and thermally stable image are desired. However SU-8 has proven to be very sensitive to variation in processing variables and hence difficult to use in the fabrication of useful structures. In this paper, negative SU-8 photoresist processed has been characterized in terms of delamination, based on a full factorial designed experiment. Employing the design of experiment (DOE), a process parameter is established, and analyzing of full factorial design is generated to investigate degree of delamination associated with three process parameters: post exposure bake (PEB) temperature, PEB time, and exposure energy. These results identify acceptable ranges of the three process variables to avoid delamination of SU-8 film, which in turn might lead to potential defects in MEMS device fabrication.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.824-827
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• 2000

Fabrication of InP-based photonic devices by dry etch Process is important for clear formation of waveguide mesa structure. We have developed more efficient etch process of the inductively coupled plasma (ICP) with low damages and less polymeric deposits for the InP-based photonic devices than the reactive ion etching (RIE) technique. We report the tendency of etch rate variation by the process parameters of the RF power, pressure, gas flow rate, and the gas mixing ratio. The surface roughness of InP-based waveguide structure was more improved by the light wet etching in the mixed solution of H$_2$SO$_4$:H$_2$O (1:1)

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 춘계학술발표대회 논문집
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• pp.218-223
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• 2000

A both mixing process of electro-magnetic stirring and mechanical process technique were used to fabricate particulate metal matrix composites(PMMCs) for variation of particle size. The PMMCs were tested for their tensile test for with and without heat treatment with T6. PMMCs fabrication processing conditions for both electrical and mechanical process are also suggested. In order to thixoforming of PMMCs, fabricated billet are reheated by using the optimal coil designed as a function of length between PMMC billet and coil surface, coil diameter and billet length. The effect of reinforcement distribution on billet temperature variation are investigated with calculated solid fraction theory proposed as a function of matrix alloy and volume fraction of reinforcement.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권6호
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• pp.771-780
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• 2016

Detecting a set of longest paths is one of the crucial steps in static timing analysis and optimization. Recently, the process variation during manufacturing affects performance of the circuit design due to nanometer feature size. Measuring the performance of a circuit prior to its fabrication requires a considerable amount of computation time because it requires multi-corner and multi-mode analysis with process variations. An efficient algorithm of detecting the K-most critical paths in multi-corner multi-mode static timing analysis (MCMM STA) is proposed in this paper. The ISCAS'85 benchmark suite using a 32 nm technology is applied to verify the proposed method. The proposed K-most critical paths detection method reduces about 25% of computation time on average.

• Smart Structures and Systems
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• 제30권1호
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• pp.35-47
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• 2022

Data-driven engineering is crucial for information delivery between design, fabrication, assembly, and maintenance of prefabricated structures. Design for manufacturing and assembly (DfMA) is a critical methodology for prefabricated bridge structures. In this study, a novel concept of digital engineering model that combined existing knowledge of DfMA with object-oriented parametric modeling technologies was developed. Three-dimensional (3D) geometry models and their data models for each phase of a construction project were defined for information delivery. Digital design models were used for conceptual design, including aesthetic consideration and possible variation during fabrication and assembly. The seismic performance of a bridge pier was evaluated by linking the design parameters to the calculated moment-curvature curves. Control parameters were selected to consider the tolerance control and revision of the digital models. Digitalized fabrication of the prefabricated members was realized using the digital fabrication model with G-code for a concrete printer or a robot. The fabrication error was evaluated and the design digital models were updated. The revised fabrication models were used in the preassembly simulation to guarantee constructability. For the maintenance of the bridge, the as-built information was defined for the prefabricated bridge piers. The results of this process revealed that data-driven information delivery is crucial for lifecycle management of prefabricated bridge piers.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 추계학술대회 논문집
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• pp.55-59
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• 1993

In this study, we developed new process for doping poly-Si film. Sb(antimony) thin film was used as doping source. Sb was evaporated on poly-Si film deposited by LPCVD fallowed by annealing. We investigate sheet resistance variation with annealing temperature and time. Finally we adapted this process to poly-Si TFT fabrication.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.714-719
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• 2004

Controlling the cure depth of the Fa1260T photopolymer enhances the quality of a microstructure and minimizes its size in microstereolithography. In this work, variation of cure depth of the Fa1260T photopolymer is investigated while the concentration of a photopolymerization inhibitor as a radical quencher was varied. The energy source inducing photopolymerization was a He-Cd laser and a motorized stage controled the laser beam path accurately. The effects of process variables such as laser beam power and scan speed on the cure depth were examined. Optimum conditions for the minimum cure depth were determined as laser power of 230 W and scan speed of 40-50 m/s at the concentration of the radical quencher of 5％. The minimum cure depth at the optimal condition was 14 m. The feasibility of the fabrication of microstructures such as a microcup, microfunnel, and microgrid of 100 m size is demonstrated using Super IH process.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.143-146
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• 2004

Fiber reinforced plastic material should be inspected in fabrication process in order to enhance quality by prevent defects such as delamination and void. Generally, ultrasonic technique is widely used to evaluate FRP. In conventional ultrasonic techniques, transducer should be contacted on FRP. However, conventional contacting method could not be applied in fabrication process and novel non-contact evaluating technique was required. Laser-based ultrasonic technique was tried to evaluate FRP plate. Laser-based ultrasonic waves propagated on CFRP were received with various transducers such as accelerometer and AE sensor in order to evaluated the properties of waves due to the variation of frequency. Velocities of laser-based ultrasonic waves were evaluated for various fiber orientation.

• 한국표면공학회지
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• 제47권6호
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• pp.362-367
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• 2014

We report the design, fabrication of a $Si_3N_4$ probe and calculation of its mechanical properties for DPN(dip pen nanolithography), which consists of dual tips. Concept of dual tip probe is to employ individual tips on probe as either an AFM tip for imaging or a writing tip for nano patterning. For this, the dual tip probe is fabricated using low residual stress $Si_3N_4$ material with LPCVD deposition and MEMS fabrication process. On the basis of FEM analysis we show that the functionality of dual tip probe for imaging is dependent on the dimensions of dual tip probe, and high ratio of widths of beam areas is preferred to minimize curvature variation on probe.

• 한국전기전자재료학회논문지
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• 제11권6호
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• pp.458-464
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• 1998

This paper gives characterization of substrate and PZT(53/47) thin film deposited by metalorganic decomposition, which is concerned in deposition process and device fabrication process, to fabricate micro electro mechanical system (MEMS) device with piezoelectric material. The PZT thin films deposited by MOD at 700^{\circ}C$ for 30 minutes had a polycrystallinity, that is, no substrate dependence, while different interface were developed depending on the bottom electrodes. Such a structural variation could influence on not only the properties of the PZT film but also etching process for fabricating MEMS devices. Therefore the electrode structure is a very important factor in the deposition of the PZT film during etching process by HF acid for MEMS device with piezoelectric material. Piezoelectric coefficients of the PZT films on the different substrates were 40 and 80 pm/V at an applied voltage of 4V. Based in these results, it was possible for deposition of the PZT film by MOD to apply MEMS device fabrication process based on piezoelectricity after selection of proper bottom electrode.