• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2004.11a
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• pp.24-24
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• 2004

• Journal of the Microelectronics and Packaging Society
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• v.21 no.3
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• pp.51-56
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• 2014

The reliability of solder joint is significantly affected by the property of surface finish. This paper reports on a study of high speed shear energy and failure mode for Sn-4.0wt%Ag-0.5wt%Cu (SAC405) solder joints with the time of Pd activation. The nodule size of electroless Ni-P deposit increased with increasing the time of Pd activation. The roughness (Ra) of electroless Ni-P deposit decreased with increasing the time of Pd activation. Then, with $HNO_3$ vapor, the quasi-brittle and brittle mode of SAC405 solder joint decreased with increasing the time of Pd activation. This results indicate that the increase in the Pd activation time for Electroless Ni/ Electroless Pd/ Immersion Au (ENEPIG) surface finish play a critical role for improving the robustness of SAC405 solder joint.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.181.2-181.2
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• 2016

OLED 소자는 발광 방향에 따라 Bottom Emission 방식과 Top Emission 방식으로 나뉜다. 이 중 대면적 OLED TV 적용에 개구율이 더 높은 Top Emission방식을 선호하는 추세이다. 높은 개구율을 가진 Top Emission OLED소자를 위해서는 투명하고 전도성이 높은 캐소드가 중요하다. 본 연구에서는 Themal Evaporation 시스템을 이용하여 증착한 $SnO_2/Ag-Pd-Cu(APC)/SnO_2$ hybrid 전극의 특성을 연구하고 Oxide/Metal/Oxide(OMO) hybrid 박막의 bending mechanism을 제시하였다. base pressure는 $1{\times}10^{-6}Torr$로 고정하고 $SnO_2$ 박막은 0.34A / 0.32V, APC 박막은 0.46A / 0.40V의 power로 성막하였다. APC와 $SnO_2$의 두께를 변수로 OMO 전극을 제작하였고 그 전기적, 광학적 특성을 Hall measurement, UV/Visible spectroscopy을 이용하여 분석하고 Figure of merit 값을 바탕으로 최적 두께를 설정하였다. UPS(Ultraviolet Photoelectron Spectroscopy) 분석으로 $SnO_2/APC/SnO_2$ 전극의 일함수을 통해 투명 cathode로 쓰였을 때 $SnO_2$ 층이 buffer layer역할을 함을 확인하였다. XPS(X-ray photoelectron spectroscopy)를 이용하여 정성분석과 정량분석을 하였고 OMO hybrid 전극의 bending mechanism 연구를 위해 다양한 bending test (Inner/Outer dynamic fatigue test, twisting test, rolling test)를 진행하였다. 물리적 힘이 가해진 OMO hybrid 전극의 표면과 구조는 FE-SEM(Field Emission Scanning Electron Microscope) 분석을 통해서 확인할 수 있었다.

• Journal of the Microelectronics and Packaging Society
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• v.12 no.1 s.34
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• pp.47-52
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• 2005

Worldwide movement for prohibition of Pb usage drives imminent implementation of Pb-free solders in microelectronic packaging industry. Reliability information of Pb-free solders has not been completely constructed yet. One of the potential reliability concerns of Pb-free solders is allotropic transformation of Sn known as tin pest. Volume increase during the formation of tin pest could deteriorate the reliability of solder joints. It was also reported that the addition of soluble elements (i.e. Pb, Bi, and Sb) into Sn can effectively suppress the tin pest. However, the mechanical properties of the tin pest resistant alloys have not been studied in detail. In this study, lap shear creep test was conducted with Sn and Sn-0.7Cu based solder alloys doped with minor amount of Bi or Sb. Shear strain rates of the alloy were generally higher than those of Sn-3.5Ag based alloys. Rupture strains and corresponding Monkman- Grant products were largest for Sn-0.5Bi alloy and smallest for Sn-0.7Cu-0.5Sb alloy. Rupture surface Sn-0.5Bi alloy showed highly elongated $\beta$-Sn globules necked to rupture by shear stresses, while elongation of $\beta$-Sn globules of Sn-0.7Cu-0.5Sb alloy was relatively smaller.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.791-797
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• 2002

This paper introduces the partial melting process for solder application and characterization of its feasibility using Sn-Ag, and Sn-Cu solder alloys. ill order to show that the liquid phase in the semi-liquid state maintains the similar wettability as single-phase liquid, the wetting balance tests are conducted with varying temperatures and compositions. Also, as a new soldering technology, the microstructural and mechanical test were investigated. The results from this research indicate that the partial melting can yield satisfactory sider joints as long as the liquid phase acquires sufficient chemical activity. At a condition where the partial melting is effective, a direct correlation between the wettability and the surface tension is found to exist.

• Journal of Welding and Joining
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• v.31 no.1
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• pp.6-10
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• 2013

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.192-192
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• 2011

본 연구에서는 LED lead frame을 위한 Sn-3.5Ag 솔더의 젖음 특성과 반사율에 관하여 조사하였다. 금속기판과 액체금속간의 젖음성은 wetting balance tester를 이용하여 평가하였으며, 최대인출력, 최대인출시간 등을 측정하고 표면장력을 계산하였다. Sn-3.5Ag 솔더를 $250{\sim}290^{\circ}C$의 온도에서 젖음성을 측정하였는데 온도가 증가함에 따라 젖음성이 향상되는 것을 확인할 수 있었다. 또한 솔더가 도금된 Cu-coupon의 반사율을 측정하였는데 $270^{\circ}C$에서 가장 높은 반사율을 나타냈다.

• Korean Journal of Metals and Materials
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• v.50 no.8
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• pp.563-568
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• 2012

The wetting property and reflectivity of Sn-3.5Ag solder which was dip coated on a LED lead frame were investigated. The wettability of molten solder on Cu substrate was evaluated by the wetting balance tester, and surface tension was calculated from maximum withdrawal force and withdrawal time. Temperature of the molten solder in a bath was varied in the range of $250-290^{\circ}C$. With increasing temperature, the surface tension decreased a little. The reflectivity of Sn-3.5Ag coated on a substrate became a little lower than the highest current LED lead frame reflectivity.

• Journal of Biomedical Engineering Research
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• v.2 no.1
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• pp.39-46
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• 1981

Microstructural phases of the dental amalgams have been studied by optical microscope, scanning electron microprobe and X-ray diffractometer. r1 ($Ag_2Hg_3$) phase and r2 ($Sn_{7-8}Hg$) phase are found on conventional compositioned alloys. On high copper single compositioned alloy, rl ($Ag_2Hg_3$) phase and V ($Cu_6Sn_5$) phase are found but brittle r2 ($Sn_(7-8)Hg$) phase.

• Proceedings of the KWS Conference
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• 2003.11a
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• pp.86-88
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• 2003

The characteristic of induction heating solder bump(solder ball: Sn-37Pb, Sn-3.5Ag, Sn-3.0Ag-0.5Cu) has analyzed in this paper. The initial condition of induction heating depends on the time and current. The shape of lead-free solder bump is better than lead solder. The shear strength of lead solder bump has decreased with aging time. The average of shear strength of solder bump is about 10N, 11N, and 11N respectively. The lead-free solder bump's shear strength is better than lead solder and varies irregularly with aging time.