• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.11
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• pp.921-925
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• 2000

Characteristics of Pb(Mg, Nb)O$_3$-Pb(Zr, Ti)O$_3$system thick films fabricated by a screen printing method were investigated. The buffer layer were coated with various thickness of Ag-Pd by screen printing to investigate the effect as a diffusion barrier and deposited Pt as a electrode by sputtering on Ag-Pb layer. The printed thick films were burned out at 650$\^{C}$ and sintered at 950$\^{C}$ in O$_2$condition for each 20, 60min after printing with 350mesh screen. The thickness of piezoelectric thick film was 15∼20㎛ and Ag-Pb layer acted as a diffusion barrier above 3㎛ thickness. The PMN-PZT thick films were screen printed on Pt/Ag-Pb(6m) and sintered by 2nd step (650$\^{C}$/20min and 950$\^{C}$/1h) using paste mixed PMN-PZT and binder in the ratio of 70:30, and the remnant polarization of thick film was 9.1$\mu$C/㎠ in this conditions.

• Korean Journal of Materials Research
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• v.18 no.1
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• pp.12-17
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• 2008

Carbon nanotube (CNT) cathodes were fabricated using nano-sized silver (Ag) powders as a bonding material between the CNTs and cathode electrodes. The effects of the powder size on the sintering behavior, the current density and emission image for CNT cathodes were investigated. As the diameter of the Ag powders decreases to 10 nm, the sintering temperature of the CNT cathode was lowered primarily due to the higher specific surface area of the Ag powders. In this study, it was demonstrated that nano-sized Ag powders can be feasibly used as a bonding material for a screen-printed CNT cathode, yielding a high current density and a uniform emission image.

• Composites Research
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• v.17 no.5
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• pp.61-67
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• 2004

This paper reports the electrical conductivity and the stress-strain behavior of silver particle-filled silicone composite pastes for electromagnetic interference (EMI) shielding gasket materials. The percolation threshold (critical concentration) of the composite paste obtained by incorporating irregular sphere-shaped silver particles and room temperature vulcanizing (RTV) silicone resin was determined from the electrical conductivity result. At about 28 vol% Beading of untreated silver particles, the percolation phenomenon occurred and at this critical concentration, the volumetric resistivity, the tensile strength, and the elongation of the pastes were investigated. This work also suggests that the stress-strain characteristics of a composite paste filled with metal particles above the percolation threshold may be effectively improved by properly selecting a coupling agent.

• ETRI Journal
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• v.35 no.4
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• pp.625-631
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• 2013

For the formation of solder bumps with a fine pitch of 130 ${\mu}m$ on a printed circuit board substrate, low-volume solder on pad (LVSoP) technology using a maskless method is developed for SAC305 solder with a high melting temperature of $220^{\circ}C$. The solder bump maker (SBM) paste and its process are quantitatively optimized to obtain a uniform solder bump height, which is almost equal to the height of the solder resist. For an understanding of chemorheological phenomena of SBM paste, differential scanning calorimetry, viscosity measurement, and physical flowing of SBM paste are precisely characterized and observed during LVSoP processing. The average height of the solder bumps and their maximum and minimum values are 14.7 ${\mu}m$, 18.3 ${\mu}m$, and 12.0 ${\mu}m$, respectively. It is expected that maskless LVSoP technology can be effectively used for a fine-pitch interconnection of a Cu pillar in the semiconductor packaging field.

• Electrical & Electronic Materials
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• v.6 no.6
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• pp.505-513
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• 1993

본 논문은 전자 부품의 Soldring기에 사용되는 접합제를 Flux를 포함한 Solder paste 대신에 도금막을 이용하기 위한 Sn 도금막 형성 프로세스를 검토한 것이다. 반도체 Device를 Packaging한 외부단자(lead frame)과 HIC상의 후막전극(Ag/Pd)과의 접합 및 PCB상의 Cu land와의 접합시에는 스크린 프린트에 의한 Solder Paste가 일반적으로 사용되고 있다. 본 논문은 Fluxless Soldering의 한수단으로 도금막을 lead상에 형성시켜 접합 재료로서의 형성 프로세스 및 도금막의 특성과 도금형성 Paramete와의 관련성을 실험적으로 검토한 것으로 전류밀도 200 A/m$^{2}$의 조건으로 형성한 Sn 도금막이 접합용으로 최적조건임을 밝혔다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.384-385
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• 2006

We studied about conductive pastes of the source-drain contacts for OTFTs(organic thin-film transistors) fabricated by direct printing(screen printing) method. We used Ag and conductive carbon black powder as the conductive fillers of pastes. The conductive pastes were manufactured by various dispersing agents and dispersing conditions and source-drain contacts with $100{\mu}m$ of channel length were fabricated. We could obtain the OTFTs which exhibited different field-effect behaviors over a range of source-dram and gate voltages depending on a kind of conductive fillers used conductive pastes.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.381-384
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• 2003

Photosensitive electordes(Ag and Black) are widely used in the patterning of both address and bus electrodes on the rear and front panel of plasma display panel (PDP). As the need for high resolution(>XGA) and large area(>60 inches) PDP is increased, basic understanding of each component of formulation on the photolithographic process of patterning electrodes are required in order to increase the yield in the production of PDP. In this work, the materials and amount of necessary components of photosensitive electrode paste and their effect on the photolithographic process of patterning electrodes were studied.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.591-592
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• 2006

We studied about the manufacture of the drain-source contacts for OTFTs(organic thin-film transistors) by using screen printing method. The conductive fillers used Ag and carbon black. The conductive contacts with $100{\mu}m$ of channel length were screen printed on a silicon dioxide gate dielectric layer and, the pentacene semiconductor was deposited via vacuum deposition. As a result of studying various conductive pastes, we could obtain the OTFTs which exhibited field-effect behavior over arrange of drain-source and gate voltages, similar to devices employing deposited Au contacts. By using screen-printing with conductive paste, the contacts are processed at low temperature, thereby facilitating their integration with heat sensitive substrates.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.8
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• pp.433-437
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• 2000

We fabricated switch module of ATM(Asynchronous Transfer Mode) exchange system with MCM-C(MultiChip Module Co-fired) technology and measured its electrical characteristics. Green tape was used as substrate and Au/Ag paste was used to form the interconnect layers. The via holes were made by drill and filled with metal paste usign screen method. After manufacturing the substrate, chips and passive components were assembled on the substrate. In electrical test, the module showed the output signal of 46.9MHz synchronized with input signal. In the view of substrate size reduction, the area of MCM switch module was 35% of conventional hybrid switch module.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.8
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• pp.461-465
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• 2016

n-type silicon shows the better tolerance towards metal impurities with a higher minority carrier lifetime compared to p-type silicon substrate. Due to better lifetime stability as compared to p-type during illumination made the photovoltaic community to switch toward n-type wafers for high efficiency silicon solar cells. We fabricated the front electrode of the n-type solar cell with AgAl paste. The electrodes characteristics of the AgAl paste depend on the contact junction depth that is closely related to the firing temperature. Metal contact depth with p+ emitter, with optimized depth is important as it influence the resistance. In this study, we optimize the firing condition for the effective formation of the metal depth by varying the firing condition. The firing was carried out at temperatures below $670^{\circ}C$ with low contact depth and high contact resistance. It was noted that the contact resistance was reduced with the increase of firing temperature. The contact resistance of $5.99m{\Omega}cm^2$ was shown for the optimum firing temperature of $865^{\circ}C$. Over $900^{\circ}C$, contact junction is bonded to the Si through the emitter, resulting the contact resistance to shunt. we obtained photovoltaic parameter such as fill factor of 76.68%, short-circuit current of $40.2mA/cm^2$, open-circuit voltage of 620 mV and convert efficiency of 19.11%.