• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.1023-1025
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• 1998

This paper presents the fabrication of a micro pump consisting of a pair of Al f1ap wave and a phase change actuator. The phase change actuator is composed of a heater, a silicone rubber diaphragm and a working liquid chamber. The diaphragm is actuated by the evaporation and the condensation of the working liquid. The actuator pumps fluid through the valves. The micro pump is fabricated by the anisotropic etch, the boron deposition and the metal evaporation. The forward and the backward flow characteristics of the f1ap valves were obtained. Also, the flow rate of the micro pump has been measured. When the square wave input of 12 V, 60% duty ratio and 0.2 Hz is applied, the average flow rate is $0.15{\mu}{\ell}/sec$ for zero pressure difference.

• Journal of Welding and Joining
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• v.32 no.3
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• pp.19-26
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• 2014

Through Silicon Via (TSV) technology is the shortest interconnection technology which is compared with conventional wire bonding interconnection technology. Recently, this technology has been also noticed for the miniaturization of electronic devices, multi-functional and high performance. The short interconnection length of TSV achieve can implement a high density and power efficiency. Among the TSV technology, TSV filling process is important technology because the cost of TSV technology is depended on the filling process time and reliability. Various filling methods have been developed like as Cu electroplating method, molten solder insert method and Ti/W deposition method. In this paper, various TSV filling methods were introduced and each filling materials were discussed.

• Journal of the Korean Magnetics Society
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• v.21 no.5
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• pp.185-192
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• 2011

The technique of producing thin film plays a crucial role in modern science and technology as well as in industrial purposes. Numerous efforts have been made to get high quality thin film through surface treatment of materials. PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition) are two of the most popular deposition techniques used in both scientific study and industrial use. It is well known that the film deposited by PVD and CVD commonly possesses a columnar microstructure which affects many film properties. In recent years, various types of deposition sources which feature high material uses and excellent film properties have been developed. Electromagnetic levitation source appeared as an alternative deposition source to realize high deposition rate for industrial use. Complex film structures such as nano multilayer and multi-components have been prepared to achieve better film properties. Glancing angle deposition (GLAD) has also been developed as a technique to engineer the columnar structure of thin films on the micro- and nanoscale. In this paper, the trends and major issues of thin film technology based on PVD and CVD have been discussed together with the prospect of thin film technology.

• Journal of the Korean Electrochemical Society
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• v.3 no.2
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• pp.115-120
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• 2000

All solid-state thin film micro-batteries consisting of lithium metal anode, an amorphous LiPON electrolyte and cathode of vanadium oxide have been fabricated and characterized, which were fabricated with cell structure of $Li/LiPON/V_2O_5Pt$. The effect of various oxygen partial pressure on the electrochemical properties of vanadium oxide thin films formed by d.c. reactive sputtering deposition were investigated. The vanadium oxide thin film with deposition condition of $20\%\;O_2/Ar$ ratio showed good cycling behavior. In in-siか process, the LiPON electrolyte was deposited on the $V_2O_5$ films without breaking vacuum by r.f. magnetron sputtering at room temperature. After deposition of the amorphous LiPON, the Li metal films were grown by a thermal evaporator in a dry room. The charge-discharge cycle measurements as a function of current density and voltage variation revealed that the $Li/LiPON/V_2O_5$ thin film had excellent rechargeable properly when current density was $7{\mu}A/cm^2$. and cut-off voltage was between 3.6 and 2.7V In practical experiment, a stopwatch ran on this $Li/LiPON/V_2O_5$ thin film micro-battery. This result means that thin film micro-battery fabricated by in-siか process is a promising for power source for electronic devices.

• Elastomers and Composites
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• v.52 no.2
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• pp.99-104
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• 2017

Due to the depletion of fossil oil and the increasing oil price, bio-plastic is currently topical. Bio-based plastics are synthesized from plant resources, unlike conventional petroleum-based counterparts. Therefore, the former minimizes global warming and reduces carbon dioxide emission. Fossil polycarbonate (PC)has good mechanical and optical properties, but its synthesis requires bisphenol-A and phosgene gas, which are toxic to humans. To address these problems, the fused deposition 3D printing process (hereafter, FDM) is studied using environmentally-friendly and high-strength bio-based PC. A comparisonof the environmental impact and tensile strength of fossil PC versus bio-based PC is presented herein, demonstrating that bio-based PC is more environmentally-friendly with higher tensile strength than fossil PC. The advantages of bio-based PC are applied in the FDM process for the fabrication of environmentally-friendly baby toys.

• Tribology and Lubricants
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• v.20 no.5
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• pp.237-244
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• 2004

Micro/nano tribological characteristics of PTFE coating films were experimentally studied. PTFE (polytetrafluoroethylene) modified polyethylene and low molecular weight PTFE were used as a coating materials. These films were deposited on Si-wafer (100) by IBAD (ion beam assisted deposition) method. The Ar ion beam sputtering was performed to change the surface topography of films using a hollow cathode ion gun under different Ar ion dose conditions in a vacuum chamber. Micro/nano tribological characteristics, water wetting angles and roughness were measured with a micro tribotester, SPM (scanning probe microscope), contact anglemeter and profilometer, respectively. The durability of the films were measured with macro tribotester. Results showed that the PTFE coating surfaces were converted to hydrophobic. The water contact angle of coated surfaces and surface roughness increased with the coating thickness. Adhesion and friction in micro and nano scale were governed by magnitude of normal load in soft material such as PTFE films. As the increase of sputtering time on low molecular weight PTFE films, the surface roughness was increased and nano adhesion and friction were decreased. The nano tribological characteristics of surfaces are mainly improved by chemical modification such as PTFE coating and given a synergy effect by the physical modification such as topographic modification.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.289-292
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• 2009

The fabrication method of glass bipolar plates for micro PEM fuel cell application has been established and performance evaluation has been carried out. The advantages of glass bipolar plates for micro PEM fuel cells are light weight, high chemical resistivity, and easy manufacture. The MEMS fabrication process of anisotropic wet etching, thermal & UV bonding along with metal layer deposition has been introduced. From performance evaluation, it was shown that the micro fuel cell with a metal layer deposited on the reactive area yielded higher power density than the one without it. But both power densities of the two cases showed out to be adequate with the current status of micro fuel cell technology.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1869-1873
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• 2008

In this work, to make it possible to generate glow discharge in atmospheric pressure condition with relatively high and wide electric field, micro channel reactor is proposed. Si DRIE and Cr deposition by Ebeam evaporation is used to make channel and bottom electrode layer. Upper electrode is made from ITO glass to visualize discharge within micro channel. Fabricated reactor is verified by generating uniform glow plasma with N2 / He gases each as working fluid. The range of gas electric field to generate glow plasma is from about 200 V/cm and upper limit is not observed in tested condition of up to 150 kV/cm. This data shows that micro channel plasma reactor is more versatile. Indirect estimation of electron temperature in this reactor can be inferred that the electron temperature within glow discharge in micro reactor lies $0{\sim}2eV$. This research demonstrates that the reactor is appropriate in application that needs to maintain low temperature condition during chemical process.

• 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.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.66.1-66.1
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• 2010

Microcrystalline silicon at low temperatures has been developed using plasma enhanced chemical vapor deposition (PECVD). It has been found that energetically positive ion and atomic hydrogen collision on to growing surface have important effects on increasing growth rate, and atomic hydrogen density is necessary for the increasing growth rate correspondingly, while keeping ion bombardment is less level. Since the plasma potential is determined by working pressure, the ion energy can be reduced by increasing the deposition pressure of 700-1200 Pa. Also, correlation of the growth rate and crystallinity with deposition parameters such as working pressure, hydrogen flow rate and input power were investigated. Consequently an efficiency of 7.9% was obtained at a high growth rate of 0.92 nm/s at a high RF power 300W using a plasma-enhanced chemical vapor deposition method (27.12MHz).