• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.12
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• pp.994-1000
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• 2001

In this paper, using micro-stereolithography technology, I fabricated a liquid analyzer to measure ion concentration of a solution. Micro-stereolithography is a technology to fabricate 3-dimensional structure by applying laser beam on liquid photo-polymer. This technology makes it possible to do preassemble fabrication without any extra assembling step after the process. So, the liquid analyzer could be fabricated at very low cost with very simple process by micro-stereolithography technology. The liquid analyzer consists of a chamber for containing the solution, a pump using piezoelectric effect of PZT disk, a static mixer and a sensor for measuring ion concentration using Pt electrodes.

• KSTLE International Journal
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• v.9 no.1_2
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• pp.10-12
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• 2008

Silicon micro-patterns were fabricated on Si (100) wafers using photolithography and DRIE (Deep Reactive Ion Etching) fabrication techniques. The patterned shapes included micro-pillars and micro-channels. After the fabrication of the patterns, the patterned surfaces were chemically modified by coating Z-DOL (perfluoropolyether, PFPE) thin films. The surfaces were then evaluated for their micro-friction behavior in comparison with those of bare Si (100) flat, Z-DOL coated Si (100) flat and uncoated Si patterns. Experimental results showed that the chemically treated (Z-DOL coated) patterned surfaces exhibited the lowest values of coefficient of friction when compared to the rest of the test materials. The results indicate that a combination of both the topographical and chemical modification is very effective in reducing the friction property. Combined surface treatments such as these could be useful for tribological applications in miniaturized devices such as Micro/Nano-Electro-Mechanical-Systems (MEMS/NEMS).

• Applied Science and Convergence Technology
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• v.23 no.1
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• pp.54-59
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• 2014

The roll-to-roll (R2R) fabrication method to make micro-scale pillar arrays for biomimetic functionalization of surfaces is presented. Inspired by the micro-structure of plants in nature, a surface with a synthetic micro-scale pillar array is fabricated via maskless photolithography. After the surface is SAM (self-assembled monolayer) coated with trichlorosilane in a vacuum desiccator, it displays a hydrophobic property even in R2R replicas of original substrate, whose properties are further characterized using various pitches and diameters. In order to perform a comparison between the original micro-pattern and its replicas, surface morphology was analyzed using scanning electron microscopy and wetting characteristics were measured via a contact angle measurement tool with a $10{\mu}L$ water droplet. Efficient roll-to-roll imprinting for a biomimetic functionalized surface has the potential for use in many fields ranging from water repelling and self-cleaning to microfluidic chips.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.5
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• pp.249-252
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• 2001

The paper represents the design and fabrication of an electrostatic micro actuator with $p^+$,/TEX> Si cantilevers. The micro actuator consists of a plate suspended by four $p^+$,/TEX> silicon cantilevers and an electrode on a glass substrate. The $p^+$,/TEX> Si structure is fabricated by the boron diffusion process and the anisotropic wet etch process. The cantilevers of the micro actuator curl down because of the residual stress gradient in $p^+$,/TEX> silicon. When the electrostatic forec is applied to the $p^+$,/TEX> cantilevers, the vertical displacement of the plate can be achieved. The deflection of the cantilever due to the residual stress gradient and the vertical displacement by electrostatic force were calculated. The displacement of the plate was measured with a laser displacement meter for various input voltages and frequencies. The feasibility of the proposed micro actuator for the applications to optical pickup devices or optical communication devices was confirmed by the experiments.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.258-259
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• 2006

New powder compaction process, in which a Bingham semi-solid/fluid mold is utilized, is developed to fabricate micro parts. In the present process, a powder material is filled as slurry in a solid wax mold, dried and compressed. The wax is heated during compaction and becomes semi-solid state, which can acts as a pressurized medium for isostatic compaction. Since the compacted micro parts are very fragile, the mold's temperature is controlled to higher than its melting point during unloading, to avoid breakage of the compacts. To demonstrate effectiveness of this process, some micro compacts of alumina are shown as examples.

• Laser Solutions
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• v.5 no.2
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• pp.17-22
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• 2002

Characteristics of micro carbon structures fabricated with laser-induced chemical vapor deposition (LCVD) are investigated. An argon ion laser (λ＝514.5nm) and ethylene gas were utilized as the energy source and precursor, respectively. The laser beam was focused onto a graphite substrate to produce carbon deposit through thermal decomposition of the precursor. Average growth rate of a carbon rod increased for increasing laser power and pressure. Micro carbon rods with good surface quality were obtained at near the threshold condition. Micro carbon rods with aspect ratio of about 100 and micro tubular structures were fabricated to demonstrate the possible application of this method to the fabrication of three-dimensional microstructures. Laser Raman spectroscopic analysis of the micro carbon structures revealed that the carbon rods are consisting of amorphous carbon.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.367-368
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• 2012

• Journal of the Korean Society for Precision Engineering
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• v.28 no.8
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• pp.966-974
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• 2011

The use of ion beams in the micro/nano scale is greatly increased by technology development. Especially, focused ion beams (FIBs) have a great potential to fabricate the device in sub micro scale. Nevertheless, FIB has several limitations, surface swelling in low ion dose regime, precipitation of incident ions, and the redeposition effect due to the sputtered atoms. In this research, we demonstrate a way which can be used to fabricate mold structures on a silicon substrate using FIBs. For the purpose of the demonstration, two essential subjects are necessary. One is that focused ion beam diameter as well as shape has to be measured and verified. The other one is that the accurate rotational symmetric model of ion-solid interaction has to be mathematically developed. We apply those two, measured beam diameter and mathematical model, to fabricate optical lenses mold on silicon. The characteristics of silicon mold fabrication will be discussed as well as simulation results.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.395-400
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• 2005

Nano-scale fabrication of silicon substrate based on the use of atomic force microscopy (AFM) was demonstrated. A specially designed cantilever with diamond tip, allowing the formation of damaged layer on silicon substrate by a simple scratching process, has been applied instead of conventional silicon cantilever for scanning. A thin damaged layer forms in the substrate at the diamond tip-sample junction along scanning path of the tip. The damaged layer withstands against wet chemical etching in aqueous KOH solution. Diamond tip acts as a patterning tool like mask film for lithography process. Hence these sequential processes, called tribo-nanolithography, TNL, can fabricate 2D or 3D micro structures in nanometer range. This study demonstrates the novel fabrication processes of the micro cantilever and diamond tip as a tool for TNL using micro-patterning, wet chemical etching and CVD. The developed TNL tools show outstanding machinability against single crystal silicon wafer. Hence, they are expected to have a possibility for industrial applications as a micro-to-nano machining tool.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.7
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• pp.298-304
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• 2003

IPMC(Ionic Polymer-Metal Composite) is a highly sensitive actuator that shows a large deformation in presence of low applied voltage. Generally, IPMC can be fabricated by electroless plating of platinum on both sides of a Nafion (perfluorosulfonic acid) film. When a commercial Nafion film is used as a base structure of the IPMC membrane, the micro-pump structure and the IPMC membrane are fabricated separately and then later assembled, which makes the fabrication inefficient. Therefore, fabrication of an IPMC membrane and the micro-pump structure on a single wafer without the need of assembly have been developed. The silicon wafer was partially etched to hold liquid Nafion to be casted and a 60-${\mu}{\textrm}{m}$ thick IPMC membrane was realized. IPMC membranes with various size were fabricated by casting and they showed 4-2${\mu}{\textrm}{m}$ displacements from $4mm{\times}4mm$ , $6mm{\times}6mm$, $8mm{\times}8mm$ membranes at the applied voltage ranging from 2Vp-p to 5Vp-p at 0.5Hz. The displacement of the fabricated IPMC membranes is fairly proportional to the membrane area and the applied voltage.