• Journal of the Korean institute of surface engineering
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• v.4 no.1
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• pp.16-23
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• 1971

In this study , fluoborte solution consisting of lead fluoborate, tin fluoborate and cupric acetate was used. By addition of small amount of Cu+= ion to the solution, the Cu content of deposition layer was almost controlled less than 5%. The amount of Cu in deposition layer was almost constant without any influence of Pb++ & Sn++ in the solution, and the amount of Pb was increased by the increase of total concentration of Pb++ +Sn++ in the solution, and the amount of Pb was increased by the increase of total concentration of Pb++ +Sn++ in the solution . Agitation of plating solution & low current density result in the increase of Cu content. Analyzing of microscopic structures and etching tests of the deposited alloy, it was believed that the alloy had a lamellar structure consisting of copper rich lamellar and lead rich layer.

• Journal of Powder Materials
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• v.16 no.4
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• pp.268-274
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• 2009

For the purpose of obtaining basic information on the development of lead-free materials, a high density composites (a) W-Cu, (b) W-Sn (c)W-Cu-Sn and (d) W-Cu-Ni were fabricated by the P/M method. The particle size of used metal powders were under 325 mesh, inner size of compaction mould was $\phi8$ mm, and compaction pressure was 400 MPa. A High density composite samples were sintered at a temperature between $140^{\circ}C$ and $1050^{\circ}C$ for 1 hour under Ar atmosphere. The microstructure, phase transformation and physical properties of the sintered samples were investigated. As the results, the highest relative density of 95.86% (10.87 g/$cm^3$) was obtained particularly in the sintered W-Cu-Sn ternary system sample sintered at 450 for 1hr. And, Rockwell hardness (HRB) of 70.0 was obtained in this system.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.4 s.33
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• pp.1-5
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• 2004

A multi-layer flexible substrate is composed of copper(Cu)/polyimide that are known as good electrical conductivity, and low dielectric constant, respectively. In this study. conductor line of $5{\mu}m$-pitch was successfully fabricated without non-uniform pattern shape by electroplating copper and coating polyimide on patterned stainless steel. For multi-layer flexible substrate, via holes were drilled by UV laser and filled with electroplating copper and tin. And then, the PI layer with vias and conductor lines was stripped from stainless steel substrate. The PI layers were laminated at once with careful alignment between layers. Solid state reaction between tin and copper during lamination formed the intermetallic compounds of $Cu_6Sn_5$($\eta$-phase) and $Cu_3Sn$($\epsilon$-Phase) and achieved a complete inter-connection by vertically positioning the plugged via holes on via pad. The via formation process has several advantages; such as better electrical property and lower cost than V type via and paste via.

• Korean Journal of Materials Research
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• v.9 no.10
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• pp.1018-1024
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• 1999

The effects of operating temperature and stress on degradation of components in high temperature steam generator were investigated. Several 2.25CrlMo tubes which had operated over 20 years and an unused 9CrlMoVNb tube were tested. For the former samples, the amount of $\textrm{M}_{6}\textrm{C}$ carbide and its size are increased with the aging or operating time. The precipitation behavior of carbides ($\textrm{M}_{2}\textrm{O}$, $\textrm{M}_{6}\textrm{C}$) is changed with the operating temperature of the tubes. However, unused 9CrlMoVNb samples show a different carbide precipitation process due to high chromium, vanadium, and niobium contents. The amount of Cr-rich $\textrm{M}_{23}\textrm{C}_{6}$ carbide is significantly increased with aging time, but that of $\textrm{M}_{6}\textrm{C}$ type carbide is rarely changed with aging time at elevated temperatures.

• Proceedings of the KWS Conference
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• 2003.05a
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• pp.34-36
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• 2003

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.804-810
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• 1997

A new catalyst system composed of a main catalyst(copper chloride) and promotors of zinc chloride, tin, and cadminum showed excellent performances in the MCS synthesis from silicon and methylchloride. The mixture of catalyst/silicon(5/95), Zn/Cu=0.1, Sn/Cu=0.001, and Cd/Cu=0.001 was mixed in a slurry phase and activated into the contact mass, then it was used for MCS synthesis. The average selectivity was 92% at the silicon consumption of 92% and reaction rate was 175(g-MCS/hr.kg-silicon) at conversion of silicon.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.7
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• pp.843-850
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• 2003

Cu/PET film composites were prepared by electroless copper plating method. In order to improve adhesion between electroless plated Cu layer and polyester (PET) film, the effect of pretreatment conditions such as etching method, mixed catalyst composition were investigated. Chemical etching and plasma treatment increased surface roughness in decreasing order of Ar＞HCl＞O$_2$＞NH$_3$. However, adhesion of Cu layer on PET film increased in the following order: $O_2$＜Ar＜HCl＜NH$_3$. It indicated that appropriate surface roughness and introduction of affinitive functional group with Pd were key factors of improving adhesion of Cu layer. PET film was more finely etched by HCI tolution, resulting in an improvement in adhesion between Cu layer and PET film. Plasma treatment with NH$_3$produced nitrogen atoms on PET film, which enhances chemisorption of Pd$^{2+}$ on PET film, resulting in improved adhesion and shielding effectiveness of Cu layer deposited on the Pd catalyzed surface. Surface morphology of Cu plated PET film revealed that Pd/Sn colloidal particles became more evenly distributed in the smaller size by increasing the molar ratio of PdCl$_2$; SnCl$_2$from 1 : 4 to 1 : 16. With increasing the molar ratio of mixed catalyst, adhesion and shielding effectiveness of Cu plated PET film were increased.d.

• Korean Journal of Materials Research
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• v.15 no.8
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• pp.536-542
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• 2005

Recently European Council(EU) published the RoHS(restriction of the use of certain hazardous substances in electrical and electronic equipment) which is prohibit the use of Pb, Hg, Cd, $Cr^{+6}$, PBB or PBDE in the electrical and electronic equipments. So EU member States shall ensure that, from 1 July 2006, new electrical and electronic equipment put on the market does not contain 6 hazardous substances. The one of the most important in electronics manufacturing process is soldering. Soldering process use the chemical substances which are applied in fluxing and cleaning processes and it can generate the malfunction of electronics caused by corrosion in the fields conditions. Therefore this study researched on the polarization and Tafel properties of Sn40Pb and Sn3.0Ag0.5Cu(SAC) solder based on the electrochemical theory. We prepared SnPb specimens which was aged in $150^{\circ}C,\;180^{\circ}C$ for 15 minutes ana Sn3.0Ag0.5Cu specimens that was aged in $180^{\circ}C,\;220^{\circ}C$ for 10 minutes. Experimental polarization curves were measured in distilled ionized water and $3.5 wt\%$, 1 mole NaCl electrolyte of $40^{\circ}C$, pH 7.5. Ag/AgCl and graphite were utilized by reference and counter electrode, respectively. To observe the electrochemical reaction, polarization test was conducted from -250 mV to +250 mV. From the polarization curves that were composed of anodic and cathodic curves, we obtained Tafel slop, reversible electrode potential(Ecorr) and exchange current density(Icorr). In these results, corrosion rate for two specimen were compared Sn3.0Ag0.5Cu with SnPb solders

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.85-87
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• 2009

Despite the success of $Cu(In,Ga)Se_2$ (CIGS) based PV technology now emerging in several industrial initiatives, concerns about the cost of In and Ga are often expressed. It is believed that the cost of those elements will eventually limit the cost reduction of this technology. one candidate to replace CIGS is $Cu_2ZnSnSe_4$ (CZTSe), fabricated by co-evaporation technique. Effects of substrate temperature of $Cu_2ZnSnSe_4$ absorber layer on the performance of thin films solar cells were investigated. As substrate temperature increased, the grain size of $Cu_2ZnSnSe_4$ films increased presumably. At a optimal condition of substrate temperature is $320^{\circ}C$, the solar cell shows a conversion efficiency of 1.79% with $V_{OC}$ of 0.213V, JSC of $16.91mA/cm^2$ and FF of 49.7%.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.4 s.37
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• pp.307-313
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• 2005

Electromigration behavior in the Sn96.5Ag3.0Cu0.5 solder lines was investigated and compared Sn96.5Ag3.0Cu0.5 with eutectic SnPb. Measurements were made for relevant parameters for electromigration of the solder, such as drift velocity, threshold current density, activation energy, as well as the product of diffusivity and effective charge number (DZ$\ast$). The threshold current density were measured to be $2.38{\times}10^4A/cm^2$ at $140^{\circ}C$ and the value represented the maximum current density which the SnAgCu solder can carry without electromigration damage at the stressing temperatures. The electromigration energy was measured to 0.56 eV in the temperature range of $110-160^{\circ}C$. The measured products of diffusivity and the effective charge number, DZ$\ast$ were $3.12{\times}10^{-10} cm^2/s$ at $110^{\circ}C$, $4.66{\times}10^{-10} cm^2/s$ at $125^{\circ}C$, $8.76{\times}10^{-10} cm^2/s$ at $140^{\circ}C$, $2.14{\times}10^{-9}cm^2/s$ at $160^{\circ}C$ SnPb solder existed incubation stage, while SnAgCu did not have incubation stage. It was thought that the diffusion mechanism of SnAgCu was different from that of SnPb.