• Title, Summary, Keyword: Lead-free

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A Comparative Study of the Fatigue Behavior of SnAgCu and SnPb Solder Joints (무연솔더(SnAgCu)와 유연솔더(SnPb)의 피로 수명 비교 연구)

  • Kim, Il-Ho;Park, Tae-Sang;Lee, Soon-Bok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.12
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    • pp.1856-1863
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    • 2004
  • In the last 50 years, lead-contained solder materials have been the most popular interconnect materials used in the electronics industry. Recently, lead-free solders are about to replace lead-contained solders for preventing environmental pollutions. However, the reliability of lead-free solders is not yet satisfactory. Several researchers reported that lead-contained solders have a good fatigue property. The others published that the lead-free solders have a longer thermal fatigue life. In this paper, the reason for the contradictory results published on the estimation of fatigue life of lead-free solder is investigated. In the present study, fatigue behavior of 63Sn37Pb, and two types of lead-free solder joints were compared using pseudo-power cycling testing method, which provides more realistic load cycling than chamber cycling method does. Pseudo-power cycling test was performed in various temperature ranges to evaluating the shear strain effect. A nonlinear finite element model was used to simulate the thermally induced visco-plastic deformation of solder ball joint in BGA packages. It was found that lead-free solder joints have a good fatigue property in the small temperature range condition. That condition induce small strain amplitude. However in the large temperature range condition, lead-contained solder joints have a longer fatigue life.

Practical Application of Sn-3.0Ag-0.5Cu Lead Free Solder in Electronic Production

  • Chae Kyu-Sang;Min Jae-Sang;Kim Ik-Joo;Cho Il-Je
    • Journal of the Microelectronics and Packaging Society
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    • v.12 no.1
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    • pp.65-71
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    • 2005
  • At present, Electronic industries push ahead to eliminate the Pb(Lead) -a hazardous material-from all products. Especially, we have performed to select the optimum standard composition of lead free alloy for the application to products for about 3 years from 2000. These days, we have the chance for applying to the mass-production. This project constructed the system for applying the lead free solders on consumer electronic products, which is one of the major products of the LG Electronics. To select the lead free solders with corresponding to the product features, we have passed through the test and applied with Sn-3.0Ag-0.5Cu alloy system to our products, and for the application to the high melting temperature composition, we secured the thermal resistance of the many parts and substrate and optimized the processing conditions. We have operated the temperature cycling test and the high temperature storage test under the standards to confirm the reliability of the products. On these samples, we considered the consequence of our decision by the operating test. For the long life time of the product, we have operated the temperature cycling test at $-45^{\circ}C\;-\;+125^{\circ}C$, 1 cycle/hour, 1000 cycles. Also we have tested the tin whisker growth about lead free plating on lead finish. We have analyzed with the SEM, EDS and any other equipment for confirming the failure mode at the joint and the tin whisker growth on lead free finish.

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Practical Application of Lead-free Solder in Electronic Products

  • Cho Il-Je;Chae Kyu-Sang;Min Jae-Sang;Kim Ik-Joo
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • pp.93-99
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    • 2004
  • At present, LG Electronics pushes ahead to eliminate the Pb(Lead) -a hazardous material- from all products. Especially, we have performed to select the optimum standard composition of lead free alloy for the application to products for about 3 years from 2000. These days, we have the chance for applying to the mass-production. This project constructed the system for applying the lead free solders on consumer electronic products, which is one of the major products of the LG Electronics. To select the lead free solders with corresponding to the product features, we have passed through the test and applied with Sn-3.0Ag-0.5Cu alloy system to our products, and for the application to the high melting temperature composition, we secured the thermal resistance of the many parts and substrate and optimized the processing conditions. We have operated the temperature cycling test and the high temperature storage test under the standards to confirm the reliability of the products. On these samples, we considered the consequence of our decision by the operating test. For the long life time of the product, we have operated the temperature cycling test at $-45^{\circ}C-+125^{\circ}C$, 1 cycle/hour, 1000 cycles. Also we have tested the tin whisker growth about lead free plating on lead finish. We have analyzed with the SEM, EDS and any other equipment for confirming the failure mode at the joint and the tin whisker growth on lead free finish.

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A Case Study of Lead-free Thick Film Conductors with Lead-containing and Lead-free Solders

  • Yu Yeon Su;Bokalo Peter;Shahbazi Samson;Matier Colleen
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • pp.1-19
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    • 2003
  • The electronic market thrust for many hybrid circuit manufacturers is changing because commercial market segments such as telecommunications, automotive and consumer electronics have increased the demand world wide for environmentally friendly thick film products. This, in turn, places a stronger emphasis on the material suppliers within the circuit fabrication industry to provide toxin free products with equal or higher performance than traditional technology. A new group of silver based thick film conductors, which are totally free of such toxins as cadmium, nickel and Bead have been developed to meet new environmental requirements. Traditional thick film products and newly developed toxin free compositions will be compared and data will be presented. To evaluate their performance, both groups of conductors were tested for solder acceptance, leach resistance and aged adhesion with standard lead-containing solder and higher temperature lead-free solder.

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Strategies of A Potential Importance, Making Lead-Free Piezoceramics Truly Alternative to PZTs

  • Kim, Hwang-Pill;Ahn, Chang Won;Hwang, Younghun;Lee, Ho-Yong;Jo, Wook
    • Journal of the Korean Ceramic Society
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    • v.54 no.2
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    • pp.86-95
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    • 2017
  • Active search for lead-free piezoceramics over the last decade has harvested a considerable amount of achievements both in theory and in practice. Few would deny that those achievements are highly beneficial, but agree that this quest of developing the lead-free piezoceramics in replace for PZTs is successfully completed. Nevertheless, few would clearly state where this quest should be directed in our next move. A source of this uncertainty may originate from the fact that it is still not clear how good is good enough to beat PZTs. In this short review, we analyzed the existing literature data to clearly locate the current state of the art of lead-free piezoceramics in comparison to PZT-based piezoceramics. Four strategies of a potential importance were suggested and discussed to help researchers plan and design their future research on lead-free piezoceramics with a recently reported exemplary work.

Microstructure and Piezoelectric Properties in the (Na,K,Li)(Nb,Sb)$O_3$ system ((Na,K,Li)(Nb,Sb)$O_3$ 세라믹스의 압전특성과 미세조직의 변화)

  • Jeon, So-Hyun;Kim, Min-Soo;Jeong, Soon-Jong;Kim, In-Sung;Min, Bok-Ki;Song, Jae-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.280-280
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    • 2007
  • Lead oxide-based ferroelectrics are the most widely used materials for piezoelectric actuators, sensors and transducers due to their excellent piezoelectric properties. Considering lead toxicity, there is great interest in developing lead-free piezoelectric materials, which are biocompatible and environmentally friendlier. Recently alkali oxide materials, including sodium - potassium niobate (NKN), have been given attention in view of their ultrasonic application and also as promising candidates for piezoelectric lead-free system. However, it is difficult to sinter such NKN-based materials via conventional sintering process. In this reason, many researchers have investigated hot press, hot isostatic press or spark-plasma sintering of NKN-based ceramics. In this study, as candidates for lead-free piezoelectric materials, dense (Na,K,Li)(Nb,Sb)$O_3$ systems were developed by conventional sintering process. The microstructures and piezoelectric properties of the (Na,K,Li)(Nb,Sb)$O_3$ systems were investigated as a function of variable compositions. The excellent piezoelectric and electromechanical properties indicate that this system is potentially good candidate as lead-free material for a wide range of electro-mechanical transducer applications.

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Analysis of Output Characteristics of Lead-free Ribbon based PV Module Using Conductive Paste (전도성 페이스트를 이용한 무연 리본계 PV 모듈의 출력 특성 분석)

  • Yoon, Hee-Sang;Song, Hyung-Jun;Go, Seok-Whan;Ju, Young-Chul;Chang, Hyo Sik;Kang, Gi-Hwan
    • Journal of the Korean Solar Energy Society
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    • v.38 no.1
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    • pp.45-55
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    • 2018
  • Environmentally benign lead-free solder coated ribbon (e. g. SnCu, SnZn, SnBi${\cdots}$) has been intensively studied to interconnect cells without lead mixed ribbon (e. g. SnPb) in the crystalline silicon(c-Si) photovoltaic modules. However, high melting point (> $200^{\circ}C$) of non-lead based solder provokes increased thermo-mechanical stress during its soldering process, which causes early degradation of PV module with it. Hence, we proposed low-temperature conductive paste (CP) based tabbing method for lead-free ribbon. Modules, interconnected by the lead-free solder (SnCu) employing CP approach, exhibits similar output without increased resistivity losses at initial condition, in comparison with traditional high temperature soldering method. Moreover, 400 cycles (2,000 hour) of thermal cycle test reveals that the module integrated by CP approach withstands thermo-mechanical stress. Furthermore, this approach guarantees strong mechanical adhesion (peel strength of ~ 2 N) between cell and lead-free ribbons. Therefore, the CP based tabbing process for lead free ribbons enables to interconnect cells in c-Si PV module, without deteriorating its performance.

Administration of Lead Acetate on the Activity of Free Radical Meta-bolizing Enzyme and Ultrastructural Changes in Rat Kidney (흰쥐에 초산납투여가 신장조직중 Free Radical 대사효소 활성과 초미형태학적 변화에 미치는 영향)

  • 김승필;윤종국;박관규
    • Toxicological Research
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    • v.11 no.1
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    • pp.57-62
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    • 1995
  • To investigate the ultrastructural changes of kidney and clarify to a cause of its changes in lead intoxicated rats, the 0.5% lead acetate administed orally to the rats and those were sacrifled at 2 day, 1, 2, 4, 6 and 8 week after the treatment of lead acetate. Each extirpated kidney was histopathologically examined under the electron microscopy and histochemical examination was also carried out. Concomitantly, the activity of free radical metabolizing enzyme was determined. The blood levels of lead concentration showed a gradual increase from the first group reaching the plateau at the one or two week group with the slightly decreasing value throughout the whole course of the experiment. And the urinary ALA concentration showed a gradual increase from the first group to the 8 week group. In the kidney tissue of rat sacrified at 6 week, the proximal tubular cells showed dilatation of endoplasmic reticulum, mitochondrial swelling, increased numbers of secondary lysosomes and myelin figure-like residual bodies on electron microscope and oxygen free radicals are identified by histochemistry on light microscope whereas there were no differences in the activity of catalase and glutathione peroxidase between the lead acetate treated group and control group. But the activity of xanthine oxidase was more increased in lead acetate treated rats than control group. Furthermore, the superoxide dismutase activity was significantly increased in the experimental group than the control group. In conclusion, it is assumed the kidney damage in lead intoxicated rat may be induced by free radicals.

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A study on the Reliability Assurance of the Electronic Equipment made with Lead-Free Solder - in the restriction of the use of hazardous substances - (유해물질 사용제한에 따라 무연솔더링 공정으로 생산된 전자제품의 신뢰성확보 방안)

  • Song Byeong-Suk;Cho Jai-Rip
    • Proceedings of the Korean Society for Quality Management Conference
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    • pp.298-301
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    • 2004
  • European Union Member States shall ensure that, from 1 July 2006, new electrical and electronic equipment put on the market does not contain mercury, cadmium, lead, hexavalent chromium, polybrominated biphenyls(PBB) or polybrominated diphenyl ethers(PBDE) (by Directive 2002/95/EC of The European Parliament and the Council of 27 january, 2003 on the restriction of the use of certain hazardous substances in electrical and electronic equipment ). So, It is important to develop lead free solder and to assure the reliability of appliance. But lead free solder(i.e. Sn-3Ag-0.5Cu) have some problems such as lift off, whisker, migration and crack, etc. In this paper we discuss the reliability assurance method in lead free solder and appliance.

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Effects of the Atmosphere on the Comparative Solderability of Lead-Tin and Lead-Free Solders

  • Bin, Jeong-Uk;S.M.Adams;P.F.Stratton
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • pp.45-47
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    • 2001
  • Due to pressure from threatened legislation in Europe, consumer and governmental pressure in Japan, and glob머 market considerations in the US, there is a rapidly growing interest in lead-free solderinger, Although the move to lead free soldering seems inevitable, many problems will arise in production assembly. It is generally acknowledged that the lead-free solders available offer a much s smaller process window than lead/tin, related mainly to the higher soldering temperatures which naturally result from increases of liquidus temperatures of at least 300 C. However, raising reflow temperatures from the current 220-2300 C to 250 2600 C will lead to problems with the boards and components as well as i increasing oxidation effects. There is a need to keep reflow temperatures low without reducing solderablity. Some results on benefits of inert atmospheres are discussed in this paper. For example, testing in a nitrogen atmosphere, with 300 ppm oxygen, by the N National Physical Laboratory (NPU has revealed clear benefits for ine$\pi$mg lead-free alloys, by restoring the solderability to lead/tin levels, by enabling lower soldering temperatures. However, there has been little testing over a range of oxygen levels in nitrogen and this is an important issue in determining n nitrogen supply and oven costs. Some results are reported here from work by NPL conducted for BOC in w which solderability was evaluated for tin기ead and tin/silver/copper eutectic a alloys in a wetting balance over a range of oxygen levels form 10 ppm to 21% ( (air). The studies confirm that acceptable wetting times occur in inert atmospheres a at soldering temperatures 20 to 300 C lower than are possible in air.

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