• Journal of the Microelectronics and Packaging Society
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• v.15 no.1
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• pp.33-37
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• 2008

A noticeable amount of Kirkendall voids formed at the Sn-3.5Ag solder joint with electroplated Cu, and that became even more significant when an additive was added to Cu electroplating bath. With SPS, a large amount of voids formed at the $Cu/Cu_3Sn$ interface of the solder joint during thermal aging at $150^{\circ}C$. The in-situ AES analysis of fractured joints revealed S segregation on the void surface. Only Cu, Sn, and S peaks were detected at the fractured $Cu/Cu_3Sn$ interfaces, and the S peak decreased rapidly with AES depth profiling. The segregation of S at the $Cu/Cu_3Sn$ interface lowered interface energy and thereby reduced the free energy barrier for the Kirkendall void nucleation. The drop impact test revealed that the electrodeposited Cu film with SPS degraded drastically with aging time. Fracture occurred at the $Cu/Cu_3Sn$ interface where a lot of voids existed. Therefore, voids occupied at the $Cu/Cu_3Sn$ interface are shown to seriously degrade drop reliability of solder joints.

• Journal of the Korean Magnetics Society
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• v.13 no.3
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• pp.121-126
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• 2003

The electromagnetic properties and microstructures of the basic composition of (N $i_{0.2}$C $u_{0.2}$Z $n_{0.6}$)$_{1.085}$(F $e_2$ $O_3$)$_{0.915}$ were invested by changing of the additive Sn $O_2$, CaO amounts and ferrite processes. There is no variation of grain size by changing additive amount. It can reduce the total loss when (N $i_{0.2}$C $u_{0.2}$Z $n_{0.6}$)$_{1.085}$(F $e_2$ $O_3$)$_{0.915}$ composition sintered at 1150 $^{\circ}C$ better than 130$0^{\circ}C$. Additive CaO confirmed of useful addition for the reduce total loss, because it increasing sintering density. Decreasing total loss were observed by adding both Sn $O_2$ 0.06 wt％ and CaO 0.4 wt％.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.191-191
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• 2015

반도체 소자 성능 향상을 위한 3차원 TSV배선 공정이 연구되었다. 전기도금을 이용한 TSV 공정 시 기존에는 황산 구리 수용액내에 억제제, 가속제, 평탄제등을 첨가한 복잡한 전해질이 사용되었지만 본 연구에서는 억제제만을 이용하여 Cu bottom-up filling에 성공하여 전해질의 조성을 단순화 시켰다.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2028-2030
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• 2005

The electrical conductivity of manganese oxide and complex manganese oxide produced by anodic deposition method was measured. The additive transition metal is Cu, Co and Fe. The transition metals like as Cu, Co and Fe improved electrical conductivity of complex manganese oxide compared with manganese oxide. This is coincide with the results of molecular orbital calculation by DV-Xa.

• Journal of Magnetics
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• v.10 no.3
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• pp.118-121
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• 2005

We have investigated the magnetic properties of electroplated thin Cu/Co multilayers by using electrolytes made of copper sulphate and cobalt sulphate and by applying alternating plating voltage. While the multilayers plated with pure electrolyte showed superparamagnetism, those plated with organic additives showed ferromagnetic behavior. These changes are attributed to the so-called 'self-annealing' effect and reduction of grain size caused by the organic additives.

• Journal of the Korean institute of surface engineering
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• v.27 no.5
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• pp.292-302
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• 1994

Alloy deposits of 80Sn-20Pb, electroplated on Cu-based leadframe alloy from an organic sulfonate bath were aged at $150^{\circ}C$ to form intermetallic phases between substrate and deposit, and effects of the deposit morphology, influenced by deposition conditions, on the fracture resistance of the 80Sn-20Pb deposit aged at $150^{\circ}C$ were examined. The growth rate of intermetallic compound layer on aging depended on the microstructure of deposit ; it was fastest in deposit formed using pulse current in bath without grain refining additive, but slowest in deposit formed using dc current in bath containing grain refining additive in spite of similar structure with equivalent grain size. The grain refining additive incorporated in electrodeposit appears to inhibit diffusion of atoms on aging, resulting in slow growth of intermetallic layer in the thickness direction but substantial growth in the lateral one. Density of surface cracks that were occurring when samples were subjected to the $90^{\circ}$-bending test increased with increasing the thickness of intermatallic layer on aging. For the same aged samples, the surface crack density of the sample electrodeposited from a bath containing the grain refining additive was the least due to the inhibiting effect of the additive incorporated into the deposit during electrolysis on atomic diffusion.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.4
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• pp.210-218
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• 2000

For the fabrication of $YBa_2Cu_3O_x$ thick film, a substrate of $Y_2BaCuO_5$ was fabricated by adding $CeO_2$ into $Y_2BaCuO_5$ and two types of doping materials added with binder material were prepared. Each doping material was patterned on $Y_2BaCuO_5$substrate by the screen printing method and then was annealed at the temperature with a few step. It could be observed by X-ray diffraction patterns and SEM photographs that through the diffusion process of the $Y_2BaCuO_5$ and each doping material, the $YBa_2Cu_3O_x$ phase was formed. And with n additive of $CeO_2$ the thickness of formed $YBa_2Cu_3O_x$decreased. From the experiment of current limiting on thick film, the sample with thiner thickness of $YBa_2Cu_3O_x$ showed the more effective characteristics of current limiting.

• Tribology and Lubricants
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• v.23 no.2
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• pp.66-72
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• 2007

[ $MoS_2$ ], is a well-known metal sulfide applied as solid lubricants and an additive to prolong the life of sintered bearings under severe conditions. However, the high price of $MoS_2$ limited its wide application. This study is aimed to investigate the possibility far application to solid lubricants for $Cu_2S$ as a substitute of $MoS_2$. Bronzes added $Cu_2S$ and $MoS_2$, are produced by powder metallurgy in this study, and then evaluated their friction and wear properties., as well as sintered bronze. The sliding wear test using pin-on-disc type machine, was conducted at several sliding speeds for three type test pieces sintered bronzes added $Cu_2S$ and $MoS_2$, and sintered bronze without lubricants. Addition of $Cu_2S$ to bronze leads to relatively good friction properties, although it is not so good as addition of $MoS_2$. However, the wear properies of sintered bronze added $Cu_2S$ are better than that of sintered bronze added $MoS_2$.

• Journal of Powder Materials
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• v.1 no.1
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• pp.79-84
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• 1994

The mechanism of activated sintering of tungsten powder was discussed in terms of diffusion and segregation of activator atoms at W grain boundaries. Shrinkage behaviours of W-0.2wt.% Ni, W-0.2wt.% Cu or pure W powder compacts during sintering at low temperatures of 900~ $1200^{\circ}C$ were investigated. It was found that the Cu additive inhibits sintering process causing lower densification than pure W compact while remarkable shrinkage occurred in the Ni added W powder. Such contrary effect was explained by comparing self diffusion processes along Ni or Cu segregated W boundaries in which Ni segregants enhance but Cu atoms retard the migration of W atoms at W boundaries.

• Bulletin of the Korean Chemical Society
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• v.13 no.3
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• pp.280-285
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• 1992

Enantiomeric separation of free amino acids has been achieved by a reversed phase liquid chromatography with addition of a Cu(Ⅱ) complex of N-alkyl-L-proline (alkyl: propyl, pentyl or octyl) to the mobile phase. The amino acids eluted were detected by a postcolumn OPA system. N-alkyl-L-proline was prepared and used as a chiral ligand of Cu(Ⅱ) chelate for the enantiomeric separation. The concentration of the Cu(Ⅱ) chelate, the organic modifier and pH affect the enantiomeric separation of free amino acids. The retention behaviour, varied with change in pH and the concentration of the Cu(Ⅱ) chelate, was different compared with those of the derivatized amino acids. The elution orders between D- and L-forms were consistent except histidine showing that L-forms elute earlier than D-forms. The retention mechanism for the enantiomeric separation can be illustrated by the stereospecificity of the ligand exchange reaction and the hydrophobic interaction between the substituent of amino acids and reversed phase, $C_18$.