Multiphase Characterization of selected isopleths of Cu-In-Sn system for Pb-free TLPB

S. TUMMINELLO; P. ALONSO; D. LAMAS; S. FRIES; S. SOMMADOSSI

Darmstadt

Congreso; Materials Science and Engineering; 2018

DGM Deutsche Gesellschaft für Materialkunde

Multiphase Characterization of Cu-In-Sn selected isopleths for Pb-free TLPBondingS. Tumminello 1,2, P. Alonso 2,3, D. Lamas2, S. Fries4, S. Sommadossi 1*ssommadossi@comahue-conicet.gob.ar1 Materials Characterization, IITCI CONICET-UNCo, Neuquen, Argentina2 Instituto Sabato, UNSAM, Buenos Aires, Argentina3 Gerencia Materiales,CAC-CNEA, Buenos Aires, Argentina4 ICAMS, RUB, Bochum, Germany*SpeakerAbstractCu-In-Sn alloys are among the suggested materials to replace Pb-Sn alloys traditionallyused in joining processes by the electronic industry. Thorough thermodynamicunderstanding is required for the selection/design of adequate and efficient alloys forspecific applications. Understanding the effects that high cost elements such as In have onmicrostructure and phase stability is imperative for industrial use. In this work ternary alloyswere prepared by melting high purity elements (5N) for selected compositions of Cuisopleths, and cooling down to reproduce process conditions. Chemical composition wasdetermined using scanning electron microscopy equipped with electron probemicroanalysis. Measurements of transition temperatures were done by heat-flux differentialscanning calorimetry. We present a comprehensive comparison between our experimentalresults and phase diagram calculations using Liu et al. (J Electron Mater 30:1093, 2001)thermodynamic description based in the CALPHAD method, available in the literature.Additionally, a structural investigation of the Cu-In-Sn intermetallic phases was carried outby comparing experimental results with simulated equilibrium diagrams. X-ray powderdiffraction (XRPD) for phases structure and SEM/EDS for microstructural analysis wereused. For each composition two types of samples were used: as melted with air cooling,and homogenized at 500 ºC during 40 days with quenching. Powders were prepared in anagate mortar and residual tensions were eliminated with adequate thermal treatments.Results indicate partial agreement between experimental data and simulated equilibriumdiagram; obtained diffractograms were compared with binary phase?s patterns, since ternaryones are not available in literature. Observed differences may be related with phasetransformations occurring far from equilibrium state in as melted samples, as a result ofheating/cooling rates in the synthesis. On the other hand, structural changes correlated withtemperature show evidence for invariant temperatures and phase fields considerations. Todeal with observed inconsistencies, additional diffraction experiments are planned bycombining other experimental techniques, as well as, a possible revision of the simulatedphase diagramsKeywords: Cu-In-Sn, lead-free joining, Intermetallics, Phase transformations,microstructure, CALPHAD, DSC, XPD.References:1. S. Fujiuchi, C. Handwerker, Masao Hirano, U. Kattner, K. Moon, H. Nawafune, and S.Katsuaki, in Lead-Free Solder. Electron., S. Katsuaki, Ed., Marcel Dekker, Inc, 2004, p 3762. X.J. Liu, H.S. Liu, I. Ohnuma, R. Kainuma, K. Ishida, S. Itabashi, K. Kameda, and K.Yamaguchi, J. Electron. Mater., 2001, 30, p 10933. W. Koester, T. Goedecke, and D. Heine, Zeitschrift Fur Met., 1972, 63, p 8024. H. Lukas, S.G. Fries, and B. Sundman, Computational Thermodynamics. The CalphadMethod, Cambridge University Press, 20075. A.T. Dinsdale, A. Watson, A. Kroupa, J. Vrestal, A. Zemanova, and J. Vizdal, COSTAction 531 - Atlas of Phase Diagrams for Lead-Free Soldering, COST Office, 2008.6. Thermo-Calc, TCSLD Database Version 3.0, 20157. T. Velikanova, M. Turchanin, and O. Fabrichnaya, Landolt-Boernstein New Ser. IV/11C3MSIT_ 249, 2007.8. S.-K. Lin, C.-F. Yang, S.-H. Wu, and S.-W. Chen, J. Electron. Mater., 2008, 37, p 4989. P. Riani, G. Cacciamani, N. Parodi, G. Borzone, R. Marazza, F. Nanni, and G. Gusmano,J. Alloys Compd., 2009, 487, p 9010. S. Sommadossi, W. Gust, and E.J. Mittemeijer, Mater. Chem. Phys., 2002, 77, p 92411. S. Sommadossi and A. Fernandez-Guillermet, Intermetallics, 2007, 15, p 91212.