• Korean Journal of Metals and Materials
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• v.48 no.1
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• pp.90-100
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• 2010

Micro-conductive patterns were microfabricated on an insulating substrate ($SiO_2$) surface by a selective electroless nickel plating process in order to investigate the formation of seed layers. To fabricate micro-conductive patterns, a thin layer of metal (Cu.Cr) was deposited in the desired micropattern using laser-induced forward transfer (LIFT). and above this layer, a second layer was plated by selective electroless plating. The LIFT process. which was carried out in multi-scan mode, was used to fabricate micro-conductive patterns via electroless nickel plating. This method helps to improve the deposition process for forming seed patterns on the insulating substrate surface and the electrical conductivity of the resulting patterns. This study analyzes the effect of seed pattern formation by LIFT and key parameters in electroless nickel plating during micro-conductive pattern fabrication. The effects of the process variables on the cross-sectional shape and surface quality of the deposited patterns are examined using field emission scanning electron microscopy (FE-SEM) and an optical microscope.

• Macromolecular Research
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• v.17 no.3
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• pp.181-186
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• 2009

We fabricated ordered micro/nano patterns induced by controlled dewetting on the topographically patterned PS/P4VP bilayer thin film. The method is based on utilizing microimprinting lithography to induce a topographically heterogeneous bilayer film that allows the controlled dewetting upon subsequent thermal annealing. The dewetting that was initiated strictly at the boundary of the thicker and thinner regions was guided by the presence of the topographic structure. The dewetting front velocity of the microdomains in the confined regions was linearly proportional to the measurement time, which enabled us to control the size of the dewet domain with annealing time. In particular, the submicron sized dot arrays between lines were generated with ease when the dewetting was confined into geometry with a few microns in size. The kinetically driven, non-lithographical pattern structures accompanied the pattern reduction to 400%. The pattern arrays on a transparent glass substrate were especially useful for non-circular microlens arrays where the focal length of the lens was easily tunable by controlling the thermal annealing.

• Journal of the Korean Society for Heat Treatment
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• v.36 no.3
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• pp.137-144
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• 2023

Micro electro mechanical systems (MEMS) and precision machines require excellent friction and wear characteristics to improve energy efficiency generated during sliding motion. In this study, DLC thin film with high hardness and low friction was deposited on STS304 substrate material by CVD method, and dot-shaped convex and concave micropatterns were fabricated by photolithography process. The diameter of the pattern was 20 ㎛, the pitch was 40 ㎛, and a pattern having a mesh type arrangement was fabricated and an abrasion test was performed. The results of the wear test on the micro pattern confirmed that the friction coefficient characteristics were improved compared to STS 304 and DLC thin films. In addition, in this result, the micro-pattern showed 11.4% more improved friction coefficient than the DLC thin film. The friction coefficient characteristics for convex and concave patterns of the same size showed almost similar results.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.2
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• pp.137-142
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• 2004

In this study, a simple procedure is described for patterning biotin on a glass substrate and then selectively immobilizing proteins of interest onto the biotin-patterned surface. Microcontact printing (CP) was used to generate the micropattern of biotin and to demonstrate the selective immobilization of proteins by using enhanced green fluorescent protein (EGFP) as a model protein, of which the C-terminus was fused to a core streptavidin (cSA) gene of Streptomyces avidinii. Confocal fluorescence microscopy was used to visualize the pattern of the immobilized protein (EGFP-cSA), and surface plasmon resonance was used to characterize biological activity of the immobilized EGFP-cSA. The results suggest that this strategy, which consists of a combination of $\mu$CP and cSA-fused proteins. is an effective way for fabricating biologically active substrates that are suitable for a wide variety of applications. one such being the use in protein-protein assays.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.6
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• pp.114-119
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• 1996

The use of holographic interference lithography and removal techniques to corrugate GaAs substrate have been studied. The periodic photoresist structure, which serves as a protective mask during etching, is holographically prepared. Subsequently periodic V-grooved pattern is formed on the GaAs substrate by conventional a H$_{2}$SO$_{4}$-H$_{2}$O$_{2}$-H$_{2}$O wet etching. The linewidth of a GaAs pattern is about 0.4$\mu$m and the depth is 0.5$\mu$m A quantum wires(QWRs) array is well formed on the V-grooved substrate by MOCVD (metalorganic chemical vapor deposition) growth of GaAs/Al$_{0.5}$Ga$_{0.5}$As (50$\AA$/300$\AA$) quantum wells. The formation of QWR array is confirmed by the temperature dependent photoluminescence (PL) measurement. The intensive PL peak with a FWHM of 6meV at 21K shows the high quality of the QWR array.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.3
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• pp.313-318
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• 2013

Magnetic abrasive polishing is an advanced deburring process for nonmagnetic materials and micropattern products that have non-machinability characteristics. Despite these advantages, there are some problems with using MAP for deburring. MAP has introduced geometric errors into microgrooves because of an over-cutting force caused by uncontrolled magnetic abrasives in the MAP tool. Thus, in this study, to solve this problem, an EP (electrolyte polishing)-MAP hybrid polishing process was developed for deburring microgrooves in an STS316 material. In addition, an evaluation of EP-MAP for the deburring of microgrooves was carried out by profiling the burrs. The results of the experiment showed geometric errors after the deburring process using MAP. However, in the case of EP-MAP, no geometric error was observed after the process because of the lower material removal rate in EP-MAP.

• Korean Chemical Engineering Research
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• v.58 no.1
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• pp.122-126
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• 2020

In this study, we produced the micropatterned channel system using polydimethylsiloxane (PDMS) and micromolding in capillaries (MIMIC) technology and evaluated cellular polarity signals through high-resolved imaging at the single-cell level. In cells treated with platelet-derived growth factor (PDGF), three types of key signals in cell migration; phosphoinositide 3-kinase (PI3 K), Rac, and Actin, were strongly activated in the front area compared to the rear region, whereas myosin light chain (MLC) showed no notable activity in the front and rear areas. Our results will, therefore, provide important information and methodology for studying the correlation between cell polarity signals and cell migration under the newly defined microenvironment.

• Korean Journal of Optics and Photonics
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• v.18 no.1
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• pp.8-13
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• 2007

In this paper, we analyze the optical properties of the transmission grating recorded in a reflection-type photopolymer. Recording and reconstruction of the micropattern using a total internal reflection hologram applied to a reflection type photopolymer are studied. The transmission-type photopolymer was shown to have the maximum diffraction efficiency in $40^{\circ}C$ symmetric structure. However, that of reflection type photopolymer was more than 90% at $60{\sim}80^{\circ}$. The line and point patterns with the interval of $1{\mu}m$ are recorded successfully and can be observed when the micro objective lenses with 10 and 100 time magnification are used.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.1
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• pp.18-23
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• 2022

Electrohydrodynamic jet (e-jet) printing, a type of direct contactless microfabrication technology, is a versatile fabrication process that enables a wide range of micro/nanopattern arrays by applying a strong electric field between the nozzle and the substrate. In general, the morphology and the thickness of polymers/quantum dot micropatterns show a systematic dependence on the diameter of the nozzle and the ink composition with a fully automated printing machine. The purpose of this report is to provide typical examples of e-jet printed micropatterns of polymers/quantum dots to explain the effect of each process variable on the result of experiments. Here, we demonstrate several operating conditions that allow high-resolution printing of layers of polymers/quantum dots with a precise control over thickness and submicron lateral resolution.