• Proceedings of the KWS Conference
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• 2006.05a
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• pp.33-35
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• 2006

The interactions between Cu/Sn-Ag-(Cu) and Sn-Ag-(Cu)/Ni interfacial reactions were studied during isothermal aging at $150^{\circ}C$ for up to 1000h using Cu(ENIG)/Sn-3.5Ag-(0.7Cu)/Cu(ENIG) sandwich solder joints. A typical scallop-type Cu-Sn intermetallic compound (IMC) layer formed at the upper Sn-Ag/Cu interface after reflowing, whereas a $(Cu,Ni)_6Sn_5$ IMC layer was observed at the Sn-Ag/ENIG interface. The Cu in the $(Cu,Ni)_6Sn_5$ IMC layer formed on the Ni side was sourced from the dissolution of the opposite Cu metal pad or Cu-Sn IMC layer. When the dissolved Cu arrived at the interface of the Ni pad, the $(Cu,Ni)_6Sn_5$ IMC layer formed on the Ni interface, preventing the Ni pad from reacting with the solder. Although a long isothermal aging treatment was performed at $150^{\circ}C$, no Ni was detected in the Cu-Sn IMC layer formed on the Cu side. Compared to the single Sn-Ag/ENIG solder joint, the formation of the $(Cu,Ni)_6Sn_5$ IMC layer of the Cu/sn-Ag/ENIG sandwich joint effectively retarded the Ni consumption from the electroless Ni-P layer.

• Journal of Korea Foundry Society
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• v.26 no.2
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• pp.92-97
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• 2006

Contact material is widely used as electrical parts. Ag-Cd alloy has a good wear resistance and stable contact resistance. But the disadvantages of Ag-Cd alloy are coarse Cd oxides and harmful metal, Cd. To solve the disadvantages of that, Ag-Sn alloy that has stable and fine Sn oxide at high temperature has been developed. In order to optimize Sn amount that affects the formation of the oxide layer on the surface, we worked for the microstructures and properties of Ag-Sn material fabricated by rapid solidification process. The experimental procedure were melting using high frequency induction, melt spinning, and internal oxidation. We have shown that the optimized Sn amount for high hardness is 7.09 wt%Sn. Surface oxide layer forms when Sn amount is over 9.45 wt%. The size of Sn oxide is 20 nm.

• Journal of the Korean institute of surface engineering
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• v.12 no.3
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• pp.161-166
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• 1979

Theoretical and practical aspects are investigated for electrochemical behavious, plating processes and the structures of electrodeposit of Pb-Sn binary alloy plating through numerous literatures in this report. The anodic and cathodic electrode reaction mechanisms of Pb and Sn could co-deposit and make Pb-Sn alloy deposit from the results of cathode current density-cathode potential curves of Pb, Sn and Pb-Sn alloys in fluoborate solutions. The compositions of the best alloy plating solutions are obtained for the purpose of bearing, anticorrosion and solder plating. In general, the casting anodes of Pb-Sn alloys are used, but separated anodes of Pb and Sn pure metal are used in order to obtain the fine compositions of Pb-Sn alloy deposits. The electrodeposits of Pb-Sn alloy are in nonequilibrium state and saturated solid solutions. Thus, ${\beta}$-phase (Sn-phase) is precipitated by heat treatment. The texture and structure of the electrodeposit are associated with the surface energies of deposit lattice planes and with the cathode polarization. The electrodeposit of Pb-Sn alloy is shown as lamellar structure.

• Journal of the Korean institute of surface engineering
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• v.22 no.1
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• pp.3-9
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• 1989

The intermetallic compount formation, growth rections, and growth kinetices as functions of the aging temperaturess, time, and the condition of substarte have invedtigted in the Sn/Cu and Sn/Ni bimetal couples. The η'-phase (Cu6Sn5) and $\delta$-phase (Ni3Sn4) were only found to grow at 20 and $70^{\circ}C$in the Sn/Cu and Sn/Ni bimetallic coples repectively. Above that temperatures, all other compounds were formed in sequence of high Sn content plase and the metastable Cu41Sn11 was formed at agend $200^{\circ}C$. The ectivation energy for the growth of intermetallic compounds was 14.7Kxal/mole in the Sn/Cu interface and 26.7Kcal/mole in the Sn/Ni interface.

• Journal of the Korean Ceramic Society
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• v.37 no.12
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• pp.1135-1139
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• 2000

본 연구에서는 Pt/Sn $O_2$박막의 CO 감지특성을 향상시키기 위하여 표면 형상을 제어하였다. Pt/Sn $O_2$계 박막센서의 최적 동작온도는 175$^{\circ}C$이었다. Pt가 12초 동안 증착된 Sn $O_2$가 200ppm의 CO 가스에 대하여 1.23의 최대감도를 나타내었고, 그 이상의 Pt 증착시간 증가에 따라 Sn $O_2$위의 Pt의 coverage가 증가하여 센서의 감도를 감소시켰다. 다층박막(multi-layer thin film)의 단층의 Pt/Sn $O_2$복합체 위에 다시 Sn $O_2$및 Pt의 cluster 층들을 연속적으로 증착함으로서 제작되었다. 단지 하나의 Pt 층만을 증착한 Sn $O_2$막보다 다층의 Pt/Sn $O_2$막이 더욱 우수한 감도( $R_{air}$/ $R_{co}$=1.72, CO: 200 ppm)를 나타내었다. Pt/Sn $O_2$다층박막의 우수한 감도의 원인은 Pt와 Sn $O_2$사이의 계면적 증대 때문인 것으로 생각되어 진다.다.

• 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.

• Korean Journal of Materials Research
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• v.9 no.4
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• pp.378-385
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• 1999

To evaluate the effect of Sn on the corrosion behavior of Zr alloys for nuclear fuel claddings, the corrosion tests on the binary Zr-xSn and the ternary Zr-0.4Nb-xSn alloys were performed in water at $360^{\circ}C$. The binary alloys containing 0.5, 0.8 and 1.5wt.% Sn showed the transition corrosion rate at 15 days. On the other hand, the binary alloy containing 2.0wt.% Sn showed a good corrosion resistance without the transition of corrosion rate up to 80 days. The corrosion rate of the ternary alloy increased with increasing Sn content. The difference of corrosion behaviors between binary and ternary alloys is considered due to the different solubility of Sn, Nb content and precipitates. The corrosions of Zr-xSn and Zr-0.4Nb-xSn alloys would be controlled by the fraction of tetragonal-$ZrO_2$and the amount of hydrogen pick-up.

• Journal of Korea Foundry Society
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• v.38 no.4
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• pp.75-81
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• 2018

This study examined the effect of the CaMgSn ternary phase on the aging response of the Mg-Sn-Zn alloy. The results revealed that the CaMgSn ternary phase formed in rod-like or needle-like shapes in Mg-3Zn-0.3Ca-xSn (x=1.5, 3, and 5 wt%) alloys and its size decreased as the Sn content increased from 1.5 wt% to 5 wt%. The Mg-3Zn-0.3Ca-5Sn alloy with a relatively fine CaMgSn phase was subjected to solution heat treatment and an aging process. Both the Mg-5Sn-3Zn-0.3Ca and Mg-5Sn-3Zn (base alloy) alloys had similar peak hardness values throughout all aging temperatures but the time-to-peak hardness in the Mg-5Sn-3Zn-0.3Ca alloy was 24-36 hours-earlier than that in the base alloy. Precipitates in the Mg-5Sn-3Zn-0.3Ca alloy were more refined than those in the Mg-5Sn-3Zn alloy and were mostly formed on basal planes. The $Mg_2Sn$ phase formed in either plate-like or rod-like shapes in the Mg-5Sn-3Zn alloy, whereas block-shaped $Mg_2Sn$ particles also formed in the Mg-5Sn-3Zn-0.3Ca alloy.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.2
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• pp.91-97
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• 2014

With Pb-free solder joints containing Sn-Ag-Cu-based ternary alloys (Sn-1.0 wt.%Ag-0.5Cu and Sn-4.0Ag-0.5Cu) and Sn-Ag-Cu-In-based quaternary alloys (Sn-1.0Ag-0.5Cu-1.0In, Sn-1.2Ag-0.5Cu-0.4In, Sn-1.2Ag-0.5Cu-0.6In, and Sn-1.2Ag-0.7Cu-0.4In), fracture-mode change, shear strengths, and fracture energies were observed and measured under a high-speed shear test of 500 mm/s. The samples in each composition were prepared with as-reflowed ones or solid-aged ones at $125^{\circ}C$ to 500 h. As a result, it was observed that ductile or quasi-ductile fracture modes occurs in the most of Sn-Ag-Cu-In samples. The happening frequency of a quasi-ductile fracture mode showed that the Sn-Ag-Cu-In joints possessed ductile fracture properties more than that of Sn-3.0Ag-0.5Cu in the high-speed shear condition. Moreover, the Sn-Ag-Cu-In joints presented averagely fracture energies similar to those of Sn-Ag-Cu joints. While maximum values in the fracture energies were measured after the solid aging for 100 h, clear decreases in the fracture energies were observed after the solid aging for 500 h. This result indicated that reliability degradation of the Sn-Ag-Cu-In solder joints might accelerate from about that time.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.3
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• pp.45-51
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• 2013

Thermal annealing tests were performed in an in-situ scanning electron microscope chamber at $130^{\circ}C$, $150^{\circ}C$, and $170^{\circ}C$ in order to investigate the effects of solder structure on the growth kinetics of intermetallic compound (IMC) in Cu/Sn-3.5Ag microbump. Cu/Sn-3.5Ag($6{\mu}m$) microbump with spreading solder structure showed $Cu_6Sn_5$ and $Cu_3Sn$ phase growths and then IMC phase transition stages with increasing annealing time. By the way, Cu/Sn-3.5Ag($4{\mu}m$) microbump without solder spreading, remaining solder was transformed to $Cu_6Sn_5$ right after bonding and had only a phase transition of $Cu_6Sn_5$ to $Cu_3Sn$ during annealing. Measured activation energies for the growth of the $Cu_3Sn$ phase during the annealing were 0.80 and 0.71eV for Cu/Sn-3.5Ag($6{\mu}m$) and Cu/Sn-3.5Ag($4{\mu}m$), respectively.