Creep Study for Fatigue Life Assessment of Two Lead-Free High Temperature Solder Alloys

Liang, Jin; Lee, P. S.; Gollhardt, Neil; Schroeder, S. A.; Morris, W. L.

doi:10.1557/proc-445-307

Cited by 13 publications

(7 citation statements)

References 1 publication

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“…Creep tests were not performed in this study but have been investigated to some extent in the published literature. [25][26][27][28] Table I represents the fitted results of creep tests on lead-free solders using these equations. Results are presented for tin-lead using Equation 2a and Equation 2b but the Garofalo fit was much better.…”

Section: Mechanical Metallurgy Of Pb-free Solder Alloysmentioning

confidence: 99%

Pb-free solders for flip-chip interconnects

Frear

Jang

Lin

et al. 2001

JOM

300

196

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Editor's Note: A hypertext-enhanced version of this article can be found at www.tms.org/pubs/journals/JOM/0106/ Frear-0106.html A variety of lead-free solder alloys were studied for use as flip-chip interconnects including , and eutectic Sn-37Pb as a baseline. The reaction behavior and reliability of these solders were determined in a flip-chip configuration using a variety of under-bump metallurgies (TiW/Cu, electrolytic nickel, and electroless Ni-P/Au). The solder microstructure and intermetallic reaction products and kinetics were determined. The Sn-0.7Cu solder has a large grain structure and the Sn-3.5Ag and Sn-3.8Ag-0.7Cu have a fine lamellar two-phase structure of tin and Ag 3 Sn. The intermetallic compounds were similar for all the lead-free alloys. On Ni, Ni 3 Sn 4 formed and on copper, Cu 6 Sn 5 Cu 3 Sn formed. During reflow, the intermetallic growth rate was faster for the lead-free alloys, compared to eutectic tin-lead. In solidstate aging, however, the interfacial intermetallic compounds grew faster with the tinlead solder than for the lead-free alloys. The reliability tests performed included shear strength and thermomechanical fatigue. The lower strength Sn-0.7Cu alloy also had the best thermomechanical fatigue behavior. Failures occurred near the solder/intermetallic interface for all the alloys except Sn-0.7Cu, which deformed by grain sliding and failed in the center of the joint. Based on this study, the optimal solder alloy for flip-chip applications is identified as eutectic Sn-0.7Cu.

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Section: Mechanical Metallurgy Of Pb-free Solder Alloysmentioning

confidence: 99%

Pb-free solders for flip-chip interconnects

Frear

Jang

Lin

et al. 2001

JOM

300

196

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“…The majority of these models use damage accumulation and predict fatigue failure based on a hysteresis-energy term or a volume-weighted average stress-strain history [19][20][21][22][23]. Syed [24] derived, for purely secondary creep, an expression for the accumulated creep damage that related the crack-growth rate to the rate of creep energy density dissipated using the C* parameter based on the NSW model [25].…”

Section: Nomenclaturementioning

confidence: 99%

A strain energy density method for the prediction of creep–fatigue damage in high temperature components

Payten

Dean²,

Snowden

2010

Materials Science and Engineering: A

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“…Similar to the common Pb-Sn eutectic alloy, all the solder alloys investigated in this paper have compositions close to their respective eutectic reaction compositions to ensure good solidification during soldering. Therefore, the microstructures of these alloys are basically two-phase eutectic structures [4]. The Ag-modified Pb-Sn eutectic alloy, 62.5Sn-36.1 Pb-1.4Ag, has a degenerated eutectic structure with some coarse eutectic colonies.…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

“…The available creep experimental data [4] has been successfully used to derive the power law and the 2-cell models for 9%-5Ag alloy.…”

Section: Cyclic Deformationmentioning

confidence: 99%

A Study of Fatigue and Creep Behaviour of Four High Temperature Solders

Liang¹,

Gollhardt²,

Lee³

et al. 1996

Fatigue Fract Eng Mat Struct

Self Cite

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Creep and cyclic deformation behavior of two lead-free high temperature solder alloys, 95Sn-5Ag and 99Sn-l.OCu, a high lead alloy 97.5Pb-1.5Ag-l.OSn. and an Ag-modified eutectic alloy 62.5Sn-36.1Pb-I.4Ag, were studied. Room temperature and high (100°C and 150°C) temperature fatigue tests (with cyclic strain amplitude up to 6.0%) for the four solders were conducted, with the fatigue lives ranging from a few cycles to more than 100, OOO cycles. It is shown that among the alloys studied, 62.5Sn-36.1Pb-1.4Ag (the modified Sn-Pb eutectic alloy) has the lowest fatigue resistance in term of low cycle fatigue life (strain controlled). The high lead alloy, 97.5Pb-l.5Ael.OSn, has the highest strain fatigue resistance in the large strain region (A& > 2.0%). Temperature has a significant effect on alloys 95Sn-5Ag and 99Sn-l.OCu, hut has a negligible effect on the Ag modified Sn-Pb eutectic alloy 62.5Sn-36.1Pte1.4Ag and 97.5Pb1.5Ag-l.OSn. Creep studies show that these alloys generally have a very significant primary creep regime (up to 20%); thus, any realistic constitutive relation has to take such a primary creep phase into consideration. Cyclic deformation of alloy 95Sn-5Ag was simulated by using a constitutive relation built upon a 2-cell model, which covers both primary and secondary creep. This model provides a good estimate of the peak stresses (the minimum stress and the maximum stress in each cycle); it agrees with experimental results when the applied cyclic strain is small and/or the applied strain rate is very low.

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Creep Study for Fatigue Life Assessment of Two Lead-Free High Temperature Solder Alloys

Cited by 13 publications

References 1 publication

Pb-free solders for flip-chip interconnects

Pb-free solders for flip-chip interconnects

A strain energy density method for the prediction of creep–fatigue damage in high temperature components

A Study of Fatigue and Creep Behaviour of Four High Temperature Solders

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