• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2004.09a
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• pp.1-26
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• 2004

The implementation of Pb-free solder technology is making good progress in electronic industry. Further understanding on fundamental issues on Pb-free solders/processes is required to reduce reliability risk factors of Pb-free solder joints. Several reliability issues including thermal fatigue, impact reliability, IMC growth, spalling, void formation are reviewed for Pb-free solder joints. Several applications of Pb-free technology are discussed, such as Pb-free, CBGA, CuCGA, flip chips, and wafer bumping by IMS.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.07a
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• pp.63-92
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• 2001

·EC's/Japanese environmental regulation drive the Pb-free/Halogen-free application ·Most Japanese electronics companies are preparing the green products. ·All items concerning to Pb-free/halogen-free technology should be coparallely designed and developed. ·More works need to clear the unknowns on Pb-free materials ·Need of consensus on materials and standards ·EBM (Environmental Benign Manufacturing)

• Journal of Welding and Joining
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• v.13 no.4
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• pp.1-6
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• 1995

Sn-Pb계 솔더는 용접, 접합성, 가격등과, 작업성이 양호하기 때문에 전자기기 실장에 사용되어 왔고, 모든 실장장치도 Sn-Pb 솔더용으로 만들어져 있다. 그러나 솔더중의 Pb는 사용할 수 없다는 분위기가 점차 확산되고 있다. 이것은 Pb가 인체에 들어가면 중추신경을 손상시킨다고 알고 있기 때문이다. Pb의 사용 규제 조치에 대해 서는 10년전 부터 미국 국회에 몇번이나 상정된 바가 있지만, Pb피해에 대해서 입증 할 수 없다는 이유로 입안이 되지 않았지만, 실제는 대체합금이 없기 때문에 입안이 되지 않은 것으로 알려져 있다. 그러나 앞으로 5년 이내에 유예기간을 두고 2000년 이후 부터 사용을 규제할 것으로 알려져 있다. 또한 북유럽에는 Pb 솔더 금지법이 의회에 제출되어 있는 것으로 알려져 있고, 곧 OECD에서도 상정될 예정이다. 결국 지구상의 환경보호 차원에서 앞으로 Pb사용이 규제될 것임은 틀립이 없다. 따라서 Pb 가 함유되어 있지 않은 솔더의 개발은 각나라 마다 핫 이슈임에 틀림이 없다. 미국 AT&T 등에서 이미 Pb Free 솔더와 공정개발에 들어가 특허화하고 있고, 특히 유럽은 연구 개발이 왕성하여 Pb Free 솔더로서 실장한 핸더폰을 생산하는 실적까지 있다. 일본도 이미 대학, 연구소, 회사로 구성된 Pb Free 솔더 연구회가 구성되어 솔더개발 에 박차를 가하고 있다. 국내에 기업체, 연구소, 학교 등에서는 이러한 긴박감을 느 끼지 못하는 것으로 사료된다. 본 해설에서는 Sn-Pb 공정계 대체 솔더인 Pb Free 솔더 의 개발 방향과 문제점을 정리하여 기술하고자 한다.

• Journal of Nutrition and Health
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• v.20 no.4
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• pp.225-236
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• 1987

This study was performed to investigate the effects of lead poisoning and different levels of dietary lipid on lead and lipid metabolism in the rats. Forty eight male weanling rats of Sprague-Dawley strain weighing 73.1$\pm$11.1g were blocked into 6 groups according to body weight. Dietary lipid were given at the lev딘 of 5, 20 and 40% of total caloric intake and lead were either administered or not. The results obtained are summerized as follows ; 1) Food intake, weight gain, F.E.R. liver and epididymal. fat pad weights, weight and length of bone, hematocrit and hemoglobin content in Pb-adminstered groups were lower than these in Pb-free groups. 2) Plasma lipid and cholesterol levels were tended to be higher in Pb-administered groups than in Pb-free groups, while liver lipid and cholesterol levels were tended to be lower in Pb-adminstered groups. 3) Fecal dry matter excretion was tended to be higher in Pb-adminstered groups than in Pb-free groups, and were increased with increasing dietary lipid level. Daily fecal excretions of lipid and cholesterol were higher in high lipid groups than in low lipid groups and these levels were even higher in the animals exposed to Pb than in Pb-free groups. 4) Pb contents in blood, liver, kidney and bone were significantly higher in Pb administered groups than in Pb-free groups. Pb levels of blood, liver and bone did not show any significant difference among groups with different levels of dietary lipid, but Pb concentration in kidney of Pb-adminstered groups increased with increasing dietary lipid level.

• Clean Technology
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• v.11 no.3
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• pp.153-164
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• 2005

This study found a reliable evaluation for four kinds of pb-Free plating solutions and it's layers, through pure Sn, SnAg, SnBi and SnCu. These four kind of solutions are widely used to pb-Free plating. Hull-cell, Harring-blum, coverage, throwing power, current efficiency, stability, life-time, composition, hardness, roughness, abrasion, scratch, solderability, corrosion, contact angle, morphology, SIR(Surface insulation resistance) and Whisker test were experimented. Also, Using ICP, XRF, FE-SEM, EDS, temperature/humidity chamber, solderability tester, hardness tester, roughness tester, abrasion tester, salt spray tester, contact angle tester, SIR tester, and microscope. In this paper could be shown the systematic and various analysis for reliability about four kinds of pb-Free plating solutions, processes and it's deposit surface.

• Proceedings of the KWS Conference
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• 2003.11a
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• pp.83-85
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• 2003

This paper is investigated the shear strength by using the micro shear-punch test method for Sn-37Pb alloy, binary and ternary alloys of environment-friendly Pb-free solder alloys which would be surely applicable to the electronic packages. As a result, in case of Max. shear strength, Sn-4Ag-0.5Cu has the highest value and Sn-37Pb has the lowest value on every condition of experiment temperature. Also, In case of Pb-free solder joint specimens, it was found that Pb-free solder alloys have higher value of shear strength than eutectic Sn-Pb solder alloy and Sn-4Ag-0.5Cu has the highest value.

• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.211-213
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• 1999

In the future, restrictions are likely to be imposed on the use of lead in the electronics industry. In dealing with such a move, we have been developing Pb-free Sn-Ag plating process to replace presently available Sn-Pb process. In this paper, the result of a basic comparison test between Sn-Pb plating and Sn-Ag plating is reported.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.2
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• pp.187-192
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• 2011

UBM(Under Bump Metallurgy) is very important for successful realization of Flip-Chip technology. In this study, it is investigated the interfacial reactions between various Sn-Ag solder alloys and Ni-P/Au UBM and Cu plate finish. It is also evaluated the shear strength by using the micro shear-punch test method for Sn-37Pb alloy, binary and ternary alloys of environment-friendly Pb-free solder alloys which are applied in the electronic packages. In terms of interfacial microstructure, the Pb-free solder joints have thicker IMCs than the Sn-Pb solder joints. The thickness of IMC is related to Reflow time. The IMC has been observed to grow with the increase in Reflow time. As a result of the shear test, in case of Max. shear strength, Pb-free solder showed the highest strength value and Sn-37Pb showed the lowest strength value 10 be generally condition of Reflow time.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.09a
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• pp.21-50
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• 2001

EC's/Japanese environmental regulation drive the Pb-free/Halogen-free application. Most Japanese electronics companies are preparing the green products. All items concerning to Pb-free/Halogen-ree technology should be coparallely designed and developed. More works need to clear the unknowns on Pb-free materials. Need of consensus on materials and standards. EBM (Environmental Benign Manufacturing)

• Journal of Welding and Joining
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• v.23 no.5
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• pp.49-54
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• 2005

The effective charge number and the critical current density of electromigration in eutetic SnPb and Pb Free $(SnAg_{3.8}Cu_{0.7)$ flip chip solder bumps are studied. The effective charge number of electromigration in eutectic SnPb solder is obtained as 34 and the critical current density is $j=0.169{\times}({\delta}_{\sigma}/{\delta}_x})\;A/cm^2,\;where\;({\delta}_{\sigma}/{\delta}_x})$ is the electromigration-induced compressive stress gradient along the length of the line. While the effect of electromigration in Pb free solder is much smaller than that in eutectic SnPb, the product of diffusivity and effective charge number $DZ^{\ast}$ has been assumed as $6.62{\times}10^{-11}$. The critical length for electromigration are also discussed.