• Nuclear Engineering and Technology
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• v.22 no.2
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• pp.108-115
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• 1990

The measurements of X-ray production cross-sections for 0.5~1.2-MeV proton beam are carried out on Cu and Au. For this experiment, the proton tram generated from the SNU 1.5-MV Tandem Van do Graaff accelerator is Incident on the target. The X-rays and the backscattered protons from the irradiated target are detected simultaneously by the Si(Li) X-ray detector and the SSB (Silicone Surface Barrier) charged particle detector The measured values of X-ray production cross-sections are compared with other experimental values and theoretical values such as the PWBA (Plane Wave Born Approximation) and the ECPSSR(Perturbed Stationary State corrected Energy loss, Coulomb deflection, Relativistic effects) values. For measured cross-sections near 1.0- MeV proton energy, the ECPSSR (D.D. Cohenet al., 1985) shows better agreement than the PWBA. Particularly, that of Au for 1.2 MeV proton beam is 9.69$\pm$ 0.39 barns which deviates from the ECPSSR by less than 5%. and the experimental data for 0.5~1.2- MeV proton agree with most of other experimental values within 30%.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.4
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• pp.155-161
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• 2018

A Si chip with the Cu/Au bumps of $100-{\mu}m$ diameter was flip-chip bonded using different anisotropic conductive adhesives (ACAs) onto the local stiffness-variant stretchable substrate consisting of polydimethylsiloxane (PDMS) and flexible printed circuit board (FPCB). The average contact resistances of the flip-chip joints processed with ACAs containing different conductive particles were evaluated and compared. The specimen, which was flip-chip bonded using the ACA with Au-coated polymer balls as conductive particles, exhibited a contact resistance of $43.2m{\Omega}$. The contact resistance of the Si chip, which was flip-chip processed with the ACA containing SnBi solder particles, was measured as $36.2m{\Omega}$, On the contrary, an electric open occurred for the sample bonded using the ACA with Ni particles, which was attributed to the formation of flip-chip joints without any entrapped Ni particles because of the least amount of Ni particles in the ACA.

• Korean Journal of Heritage: History & Science
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• v.54 no.1
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• pp.4-17
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• 2021

This study analyzed 19 samples of harness fittings and pendants, which were excavated in Tomb No. 15 in Songhyeon-dong, Changnyeong. Harness fittings and pendants are used for ostentation, rather than practicality, and were excavated from ancient tombs in Gaya culture. So, they are considered artifacts that compare the production techniques and raw materials. This study aimed to examine the production techniques and provenience studies of Bihwa Gaya, which is estimated to be from the 5th to 6th centuries. According to the research, harness fittings were made of pure copper and were gilded with Au·Ag alloys on their surfaces. Hg was detected together and plated with a mercury amalgam method. As a result of the pendant (fish scales-pattern, oval and fish-tail shape), analysis showed that Fe in the background metal, Cu in the middle layer, and Au and Ag on the surface were the main components. The method of adhesion between Cu and Au·Ag gilded layers are plated by a mercury amalgamation method. So, it was identified by the gilt-iron·gold·bronze technique. Since the pendant (heart shaped) is found to be the main component of Fe in the background metal and Ag in the surface layer, the metal was made gilt-iron·silver technique. The background metal and gilding were additionally fixed using a rivet. The raw materials of 3 harnesses excavated from Changnyeong are plotted in zone 2 in the southern Korean Peninsula. And 16 harnesses were plotted in Chinese copper ore by Mabuchi Hishao in the Chinese Peninsula.

• Journal of Conservation Science
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• v.16 s.16
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• pp.52-63
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• 2004

This study tries to investigate the differences in combination of gold and other metals used in the surface guilt of the gold-guilt relics found in the Seonwonsa Temple of the Korea Dynasty. Our findings are as follows. The gilded roller knobs found in the Seonwonsa Temple of the Korea Dynasty can be classified into three groups by the color of the surface guilt: gold, white-gold, red-gold. By the color it is found that gold type contains $Au\;81.0\%,\;Ag\;3.5\%,\;Cu\;5.6\%$, white-gold type contains $Au\;82.1\%,\;Ag\;10.6\%,\;Cu\;2.4\%$, and the red-gold type contains $Au\;59.9\%,\;Ag\;3.7\%,\;Cu\;33.2\%$. The gold metal used for guilt is found to be amalgam of Hg and the depth of the guilt was uneven with the average of $2.5\~25{\mu}m$. These gilded roller knobs were produced in two methods. One of them was made out of pure bronze, and the other out of bronze veneer and led. Since we found led on the outer surface, we conclude that the led juncture was later guilt with gold.

• Journal of the Microelectronics and Packaging Society
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• v.18 no.4
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• pp.49-53
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• 2011

High-speed Cu filling into a through-silicon-via (TSV) and simplification of bumping process by electroplating for three dimensional stacking of Si dice were investigated. The TSV was prepared on a Si wafer by deep reactive ion etching, and $SiO_2$, Ti and Au layers were coated as functional layers on the via wall. In order to increase the filling rate of Cu into the via, a periodic-pulse-reverse wave current was applied to the Si chip during electroplating. In the bumping process, Sn-3.5Ag bumping was performed on the Cu plugs without lithography process. After electroplating, the cross sections of the vias and appearance of the bumps were observed by using a field emission scanning electron microscope. As a result, voids in the Cu-plugs were produced by via blocking around via opening and at the middle of the via when the vias were plated for 60 min at -9.66 $mA/cm^2$ and -7.71 $mA/cm^2$, respectively. The Cu plug with a void or a defect led to the production of imperfect Sn-Ag bump which was formed on the Cu-plug.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.3
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• pp.85-91
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• 1999

$H:LiNbO_3$ optical modulator with Cu/parylene electrode layer, which has a merits in the bandwidth, power consumption and fabrication conditions as compared with conventional Au/Cr/$SiO_2$, is proposed and fabricated. Analysis and design of optical modulator is performed by finite element calculation. Various unit processes for fabricating the proposed modulator, 1550nm $H:LiNbO_3$ optical waveguide, parylene buffer layer, and CPW Cu electrode, were developed, After dicing and end-face polishing of fabricated modulator chip, optical modulation responses as sawtooth electrical driving voltage has been measured at low frequencies. Properties of optical waveguide had not been changed before and after Cu/parylene electrode processes, which make confirm the reproducible fabrication of optical modulator.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.259-259
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• 2008

The LTCC (Low Temperature Co-fired Ceramic) technology meets the requirements for high quality microelectronic devices and microsystems application due to a very good electrical and mechanical properties, high reliability and stability as well as possibility of making integrated three dimensional microstructures. The wet process, which has been applied to the etching of the metallic thin film on the ceramic substrate, has multi process steps such as lithography and development and uses very toxic chemicals arising the environmental problems. The other side, Plasma technology like ion beam sputtering is clean process including surface cleaning and treatment, sputtering and etching of semiconductor devices, and environmental cleanup. In this study, metallic multilayer pattern was fabricated by the ion beam etching of Ti/Pd/Cu without the lithography. In the experiment, Alumina and LTCC were used as the substrate and Ti/Pd/Cu metallic multilayer was deposited by the DC-magnetron sputtering system. After the formation of Cu/Ni/Au multilayer pattern made by the photolithography and electroplating process, the Ti/Pd/Cu multilayer was dry-etched by using the low energy-high current ion-beam etching process. Because the electroplated Au layer was the masking barrier of the etching of Ti/Pd/Cu multilayer, the additional lithography was not necessary for the etching process. Xenon ion beam which having the high sputtering yield was irradiated and was used with various ion energy and current. The metallic pattern after the etching was optically examined and analyzed. The rate and phenomenon of the etching on each metallic layer were investigated with the diverse process condition such as ion-beam acceleration energy, current density, and etching time.

• Journal of Welding and Joining
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• v.20 no.4
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• pp.505-509
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• 2002

Pb is considered to be eliminated from solder, due to its toxicity. However, melting temperatures of most Pb-free solders are known higher than that of Sn37Pb. Therefore, there is a difficulty to apply Pb-free solders to electronic industry. Since Sn3Ag8Bi5In has relatively lower melting range as $188~200^{\circ}C$, on this study. Wettability and soldering characteristics of Sn3Ag8Bi5In solder in BGA were investigated to solve for what kind of problem. Zero cross time, wetting time, and equilibrium force of Sn3Ag8Bi5In solder for Cu and plated Cu such as Sn, Ni, and Au/Ni-plated on Cu were estimated. Plated Sn on Cu showed best wettability for zero cross time, wetting time and equilibrium farce. Shear strength of the reflowed joint with Sn3Ag8Bi5In ball in BGA was investigated. Diameter of the ball was 0.5mm, UBM(under bump metallurgy) was $Au(0.5\mu\textrm{m})Ni(5\mu\textrm{m})/Cu(18\mu\textrm{m})$ and flux was RMA type. For the reflow soldering, the peak reflow temperature was changed in the range of $220~250^{\circ}C$, and conveyor speed was 0.6m/min.. The shear strength of Sn3Ag8Bi5In ball showed similar level as those of Sn37Pb. The soldered balls are aged at $110^{\circ}C$ for 36days and their shear strengths were evaluated. The shear strength of Sn3Ag8Bi5In ball was increased from 480gf to 580gf by aging for 5 days.

• Journal of the Microelectronics and Packaging Society
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• v.15 no.4
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• pp.1-7
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• 2008

We studied a growth behavior of Intermetallic compounds(IMCs) during solder bumping with two reflow methods. Ti(50 nm), Cu($1{\mu}m$), Au(50 nm) and Ti(50 nm) thin films were deposited on $SiO_2$/Si wafer using the DC magnetron sputtering system as the under bump metallization(UBM). And the $5{\mu}m$ thick Cu bumps and $20{\mu}m$ thick Sn bumps were fabricated on UBM by electroplating. Sn bumps were reflowed in RTA(Rapid Thermal Annealing) system and convection reflow oven. When RTA system was used, reflow was possible without using flux and IMC thickness formed in the solder interface was thinner than that of a convectional method.

• Journal of Powder Materials
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• v.11 no.3
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• pp.193-201
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• 2004

1960년 Au-Si계 합금에서 처음으로 비정질상이 급속 응고법에 의해 보고된 이래/sup 1)/ 지난 40년 간 많은 합금계에서 비정질상이 보고되어졌다. 대표적으로 Fe-, Ni-, Co기 합금 등 많은 합금계에서 비정질상이 보고되었으나, 비정질상의 형성을 위해서는 약 105 K/s이상의 높은 냉각속도를 필요로 하였다. 1980년대 수백 K/s의 낮은 냉각속도 하에서도 비정질상이 형성될 수 있는 다원계 합금(multi-component alloy)이 Mg-Ln-(Ni, Cu, Zn), Ln-Al-TM 합금에서 보고되어 졌으나 많은 관심을 받지 못하다가 1993년 Zr-Ti-Ni-Cu-Be 합금에서 수 ㎝ 크기의 비정질합금 제조가 보고되면서 전 세계적으로 많은 관심을 받게 되었다. Zr-Ti-Ni-Cu-Be계 벌크 비정질 합금이 보고된 후 Zr-(Nb,Pd)-Al-TM, Pd-Cu-Ni-P, Fe-Co-Zr-Mo-W-B, Ti-Zr-Ni-Cu-Sn등 여러 합금계에서 벌크 비정질 합금이 보고되었다. (중략)