• Journal of the Microelectronics and Packaging Society
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• v.28 no.2
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• pp.59-64
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• 2021

System-in-package (SIP) technology using heterogeneous integration is becoming the key of next-generation semiconductor packaging technology, and the development of low temperature Cu bonding is very important for high-performance and fine-pitch SIP interconnects. In this study the low temperature Cu bonding and the anti-oxidation effect of copper using porous Ag nanolayer were investigated. It has been found that Cu diffuses into Ag faster than Ag diffuses into Cu at the temperatures from 100℃ to 200℃, indicating that solid state diffusion bonding of copper is possible at low temperatures. Cu bonding using Ag nanolayer was carried out at 200℃, and the shear strength after bonding was measured to be 23.27 MPa.

• Korean Journal of Metals and Materials
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• v.47 no.12
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• pp.842-851
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• 2009

The long-term reliability of Sn-0.3wt%Ag-0.7wt%Cu solder joints was evaluated and compared with Sn-3.0wt%Ag-0.5wt%Cu under thermal shock conditions. Test vehicles were prepared to use Sn-0.3Ag-0.7Cu and Sn-3.0Ag-0.5Cu solder alloys. To compare the shear strength of the solder joints, 0603, 1005, 1608, 2012, 3216 and 4232 multi-layer ceramic chip capacitors were used. A reflow soldering process was utilized in the preparation of the test vehicles involving a FR-4 material-based printed circuit board (PCB). To compare the shear strength degradation following the thermal shock cycles, a thermal shock test was conducted up to 2,000 cycles at temperatures ranging from $-40^{\circ}C$ to $85^{\circ}C$, with a dwell time of 30 min at each temperature. The shear strength of the solder joints of the chip capacitors was measured at every 500 cycles in each case. The intermetallic compounds (IMCs) of the solder joint interfaces werealso analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results showed that the reliability of Sn-0.3Ag-0.7Cu solder joints was very close to that of Sn-3.0Ag-0.5Cu. Consequently, it was confirmed that Sn-0.3Ag-0.7Cu solder alloy with a low silver content can be replaced with Sn-3.0Ag-0.5Cu.

• Journal of the Korean Applied Science and Technology
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• v.38 no.3
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• pp.662-668
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• 2021

The aim of the present study was to design ascorbyl glucoside (AG) loaded solid lipid nanoparticles (SLNs) to improve skin penetration of AG. AG loaded SLNs were prepared using double emulsion method. The prepared AG loaded SLNs investigated particle characteristics (particle size, polydispersity index, zeta potential, loading capacity). Skin penetration study was carried out using SkinEthic RHE as one of the reconstructed human epidermis models. The mean particle size and zeta potential of SLNs were 172.65 - 347.19 nm and -22.90 - -41.20 mV, respectively. The loading capacity of AG loaded SLNs demonstrated that loading efficiency and loading amount were ranged from 44.18% to 57.77% and 12.83% to 16.15%, respectively. The results of penetration showed that all SLNs enhanced the skin penetration of AG and the amount of AG from SLNs were approximately 3.7 - 7.4 times higher than that from AG solution. Therefore, AG loaded SLN might be a promising topical drug delivery system.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.10a
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• pp.99-103
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• 1997

활성탄의 특성을 이용하여 상업적으로 문제시되고 있는 수질 및 공기 정화용 항균성 Ag-활성탄을 제조하여 흡착특성, 표면구조 및 박테리아 저항성에 대하여 조사하였다. 높은 비표면적을 가진 활성탄에 대하여 AgNO$_3$를 사용하여 Ag-활성탄을 제조하였다. 0.1에서 1.0까지의 AgNO$_3$ 몰농도에 침적된 Ag-활성탄의 비표면적 값은 874-1475 $m^2$/g의 범위에 분포하고 있었으며, AgNO$_3$몰농도가 증가함에 따라 비표면적이 작아지는 경향을 나타내어 흡착된 Ag가 원료 활성탄의 표면구조에 영향을 주었다. Ag는 활성탄 표면의 기공 주위에 고르게 분포되었으며 활성탄의 표면에 물리적 흡착에 의해 존재하는 것으로 나타났다. 항균실험을 위하여 박테리아로서 대장균의 일종인 Escherichia coli를 사용하였으며, 흡착된 Ag의 양이 증가됨에 따라 활성의 범위가 증가되었고, Ag가 흡착되지 않은 활성탄의 경우에 있어서는 활성을 전혀 나타내지 않았다.

• Journal of Powder Materials
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• v.5 no.2
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• pp.139-144
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• 1998

We have evaluated the role of Ag additions on the strength, fracture toughness, elastic modulus and resistance to thermal shock of $YBa_2Cu_3O_{7-x}$(YBCO) superconductor. Addition of 10 vol.% Ag improved strength and fracture toughness, whereas, decreased elastic modulus of YBCO. In addition, YBCO-Ag composites improved resistance to thermal shock probably due to enhanced strength, fracture toughness and thermal conductivity as a result of Ag addition. It is to be noted that YBCO-Ag made by mixing with $AgNO_3$ solution showed slightly higher strength, fracture toughness and resistance to thermal shock, compared to that made by mixing with metallic Ag powder. These improvements are believed to be due to the microstructure of more finely and uniformly distributed Ag particles.

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.11a
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• pp.171-173
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• 1996

Ag coating on the textured YBCO was prepared by means of a Ag$_2$O brushed coating method. The contact between Ag coating and textured YBCO was examined by sharp knife cut and by the observation of SEM. The critical current densities of different textured YBCO samples, which included YBCO with and without Ag coating, and YBCO with Ag coating after hot moist text, were compared. The Ag coating does not influence the oxygen absorption of textured YBCO, but Ag coating can protect YBCO well from moisture and $CO_2$

• Korean Journal of Materials Research
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• v.13 no.9
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• pp.555-560
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• 2003

Ag-coated Cu particles were prepared by dropping method of coating agent and were evaluated by scanning electron microscope and color difference meter. The shape of Cu particles having obvious crystal plan and edge was changed spherically according to the increase of Ag coating amount. When the Ag coating amount was 50 wt% to Cu particles, the whiteness of Ag-coated Cu particles was almost similar to that of pure Ag particles. Adding $NH_4$OH in reductant solution could increase effectively the whiteness of the Ag-coated particles. The Ag-coated particles having the highest whiteness was obtained when the content of hydrazine in reductant solution was 0.48 M.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1342-1344
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• 1994

Silver-Nickel alloy has been used as a electrical contact material for low voltage, low current. Since the solubility between Ag and Ni is very low, it is difficult to produce Ag-Ni alloy by using conventional melting method and disperse Ni powder homogeneously in Ag matrix. In this study we have been produced fine Ag-Ni alloy powder by using coprecipitation method. Firstly, we have produced silver-nickel nitrate solution by dissolving the Ag and Ni ingot in nitric acid solution and then, coprecipitate (Ag, Ni)carbonate dropping Ag-Ni nitrate solution to sodium carbonate solution. (Ag, Ni) carbonate is heat-treated in $H_2$ atmosphere, $400^{\circ}C$ and it has been analysed by TGA, SEM, XRD, ICP. It is represented Silver-Nickel alloy powder in the particle range of $0.1{\sim}0.5{\mu}m$.

• Journal of the Korean institute of surface engineering
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• v.35 no.1
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• pp.11-16
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• 2002

As environmental concerns increasing, the electronics industry is focusing more attention on lead free solder alternatives. In this research, we have researched wettability of intermediate solder of Sn3Ag9Bi5In, which include In and Bi and has similar melting temperature to Sn37Pb eutectic solder. We investigated the wetting property of Sn3Ag9Bi5In. To estimate wettability of Sn3Ag9Bi5In solder on various substrates, the wettability of Sn3Ag9Bi5In solder on high-pure Cu-coupon was measured. Cu-coupon that plated Sn, Ni and Au/Ni and Si-wafer adsorbed Ni/Cu under bump metallurgy on one side. As a result, the wetting property of Sn3Ag9Bi5In solder is a little better than that of Sn37Pb and Sn3.5Ag.

• Environmental Engineering Research
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• v.15 no.1
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• pp.23-27
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• 2010

Genotoxic- and ecotoxic assessments of silver nanoparticles (AgNPs) were conducted on the freshwater crustacean Daphnia magna. AgNPs may have genotoxic effects on D. magna, given that the DNA strand breaks increased when exposed to this nanoparticle. Increased mortality was concomitantly observed with DNA damage in the AgNPs-exposed D. magna, which suggests AgNPs-induced DNA damage might provoke higher-level consequences. The results of the comparative toxicities of AgNPs and Ag ions suggest that AgNPs are slightly more toxic than Ag ions. Overall, these results suggest that AgNPs may be genotoxic toward D. magna, which may contribute to the knowledge relating to the aquatic toxicity of AgNPs on aquatic ecosystems, for which little data are available.