• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.154-154
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• 2006

Samsung Electro Mechanics ink jet has developed ultra high resolution alignment system. The alignment system has been developed for repeatable printing of conductive ink. The resolution of alignment system is 0.5um and the velocity of printing working plate is 1.5m/s. So far repeated printing results included sintering process have over 30um of drop mislocation data. In order to improve line thickness and conductivity of metal line, we need to develop the higher mechanical accurate align system. On the demand, this developed align system has under $1{\sim}2{\mu}m$ mispositioning performance and can measure of mechanical accuracy of inkjet printer, as well as the straightness of jetted drop from inkjet head. There is no kinds limit of substrate and ink to use SEM alignment system. By using this alignment system, we progress two experiment of reiterate printing drop and making conductive line on the glass and photo paper. Optical microscope and 3D profiler has been used for measurement of printed ink.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.348-348
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• 2009

The conductive coating method is used for various industrial fields. For example, Sputtering process is used to coat ITO layer in LCD or OLED panel manufacture process and fabricate a base layer of substrate of an electric printing device. However, conventional coating processes (beam sputtering, spin coating etc.) has a problems in the industrial manufacturing process. These processes have a very high cost and critical manufacturing environment as a vacuum process. Recently, many researchers have proposed various printing process instead of conventional coating processes. In this paper, we propose an ESD printing process in ITO coating layer and apply to fabricate a conductive coating film. Furthermore, the effect of the nozzle and also the applied voltage on different configuration of the nozzle head was also studied for better understanding of the Electro Static deposition process.

• Journal of the Korean Ceramic Society
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• v.34 no.10
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• pp.1092-1098
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• 1997

Electrical discharge machining (EDM) was attempted on a ceramic matrix composite containing non-conductive alumina as a matrix and conductive titania as a second phase, and was found successful. As the current or duty factor increased, the material removal rate (MRR) increased and the surface roughness also increased. The EDMed surface was covered with a number of craters of a circular shape having 100-200 microns of diameter. The melting and evaporation was suggested for the EDM mechanism. The bending strength decreased 44% after EDM, but the Weibull modulus increased more than twice. Combination of EDM and barre이 polishing resulted in the maintenance of the bending strength level. Temperature distribution near a spark in the sample was computer-simulated by use of finite element method, and was found to have similar shape to the one which the observed craters have.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.72-78
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• 2009

For the electro-discharge machining of an electro-conductive anisotropic composite, an unsteady state formulation was established and solved by Galerkin's finite element method. The distribution of temperature on work piece, the shape of the crater and the material removal rate were obtained in terms of the process parameters. The $12{\times}12$ irregular mesh that was chosen as the optimum in the previous analysis was used for computational accuracy and efficiency. A material having the physical properties of alumina/titanium carbide composite was selected and an electricity with power of 51.4 V and current of 7 A was applied, assuming the removal efficiency of 10 % and the thermal anisotropic factors of 2 and 3. As the spark was initiated the workpiece immediately started to melt and the heat affected zone was formed. The moving boundary of the crater was also identified with time. When the radial and axial conductivities were increased separately, the temperature distribution and the shape of the crater were shifted in the radial and axial directions, respectively. The material removal rate was found to be higher when the conductivity was increased in the radial direction rather than in the axial direction.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.217-220
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• 2009

Conductive adhesives have been investigated for use in microelectronics packaging as a lead-free solder substitute due to their advantages, such as low bonding temperature. However, high resistivity and poor mechanical behavior may be the limiting factors for the development of conductive adhesives. The metal fillers and the polymer resins provide electrical and mechanical interconnections between surface mount device components and a substrate. As metal fillers used in conductive adhesives, silver is the most commonly used due to its high conductivity and the stability. However the cost of conductive adhesives with silver fillers is much higher than usual lead-free solders and silver has poor electro-migration performance. So, copper can be a promising candidate for conductive filler metal due to its low resistivity and low cost, but oxidation causes this metal to lose its conductivity. In this study, electrically conductive adhesives (ECAs) using surface modified copper fillers were developed. Especially, in order to overcome the problem associated with the oxidation of copper, copper particles were coated with silver, and the silver-coated copper was tested as a filler metal. Especially the effect of silver coating on the electrical resistance just after curing and after aging was investigated. As a result, it was found that the electrical resistance of ECA with silver-coated copper filler was clearly lower and more stable than that of ECA with pure copper filler after curing process. And, during high temperature storage test, the degradation rate of electrical resistance for ECA with silver coated copper filler was quite slower than that for ECA with pure copper filler.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.53-53
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• 2010

The development of synthetic pathway to produce a highly yield nanoparticles is an important aspect of industrial technology. Herein, we report a simple, rapid approach to synthesize organic-soluble Cu and Ag nanoparticles in colloidal method for the application in a conductive pattern using inkjet printing. The silver nanoparticles have been synthesized in highly concentrated organic phase. The Cu nanoparticles have been synthesized by the reducing of the copper oxide materials using acid molecules in high concentrated organic phase. Their sintering and electric conductivity properties were investigated by melting process between $200^{\circ}C$ and $250^{\circ}C$ for application to printed electronics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.413-413
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• 2008

최근 잉크젯, 스크린, 그라비아 등 기존의 인쇄 방식과 인쇄 기술을 이용하여 저가의 전자회로 혹은 전자 소자를 제조하고자 프린팅 소재 및 공정 개발에 대한 산업계의 관심이 증가하고 있다. 특히 PCB, RFID, 디스플레이, 태양전지 분야의 전극재료의 개발에 많은 연구가 진행 중에 있으며, 다양한 인쇄 방법 중 미세회로의 구현이 가능한 잉크젯 프린팅을 통한 전극 형성방법에 주목하고 있다. 본 연구는 잉크젯 프린팅 방식을 통해 배선을 형성하고자 이에 적합한 다양한 농도의 잉크를 배합하여 평가하였으며, 첨가제 및 소결, 건조 조건의 변화를 통해 기재와의 부착력, 배선의 크랙을 조절하였다.

• Journal of Mechanical Science and Technology
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• v.19 no.2
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• pp.496-504
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• 2005

The thermal and mechanical properties of an electro-slag cast steel of a similar chemical composition with an AISI-6F2 steel are investigated and compared with a forged AISI-6F2 steel. AISI-6F2 is a hot-working tool steel. Electro-slag casting (ESC) is a method of producing ingots in a water-cooled metal mold by the heat generated in an electrically conductive slag when current passes through a consumable electrode. The ESC method provides the possibility of producing material for the high quality hot-working tools and ingots directly into a desirable shape. In the present study, the thermal and mechanical properties of yield strength, tensile strength, hardness, impact toughness, wear resistance, thermal fatigue resistance, and thermal shock resistance for electro-slag cast and forged steel are experimentally measured for both annealed and quenched and tempered heat treatment conditions. It has been found that the electro-slag cast steel has comparable thermal and mechanical properties to the forged steel.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.3
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• pp.246-254
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• 2022

Localized heat can be generated using electrically conductive word-lines built into a 3D NAND flash memory string. The heat anneals the gate dielectric layer and improves the endurance and retention characteristics of memory cells. However, even though the electro-thermal annealing can improve the memory operation, studies to investigate material failures resulting from electro-thermal stress have not been reported yet. In this context, this paper investigated how applying electro-thermal annealing of 3D NAND affected mechanical stability. Hot-spots, which are expected to be mechanically damaged during the electro-thermal annealing, can be determined based on understanding material characteristics such as thermal expansion, thermal conductivity, and electrical conductivity. Finally, several guidelines for improving mechanical stability are provided in terms of bias configuration as well as alternative materials.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.9
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• pp.793-797
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• 2005

This study introduces Electro-chemical Mechanical Deposition(ECMD) lot making Cu interconnect. ECMD is a novel technique that has ability to deposit planar conductive films on non-planar substrate surfaces. Technique involves electrochemical deposition(ECD) and mechanical sweeping of the substrate surface Preferential deposition into the cavities on the substrate surface nay be achieved through two difference mechanisms. The first mechanism is more chemical and essential. It involves enhancing deposition into the cavities where mechanical sweeping does not reach. The second mechanism involves reducing deposition onto surface that is swept. In this study, we demonstrate ECMD process and characteristic. We proceeded this experiment by changing of distribution of current density on divided water area zones and use different pad types.