### Electronic structure mechanism for the wettability of Sn-based solder alloysElectronic structure mechanism for the wettability of Sn-based solder alloys

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 Author Feng, Wufeng ♦ Wang, Chunqing ♦ Morinaga, M. Source SpringerLink Content type Text Publisher Springer-Verlag File Format PDF Copyright Year ©2002 Language English
 Subject Domain (in DDC) Natural sciences & mathematics ♦ Chemistry & allied sciences Subject Keyword Sn-based solder ♦ quantum theory ♦ relativistic DV-Xα calculation ♦ orbital interaction ♦ wettability ♦ electronic mounting ♦ packaging ♦ Optical and Electronic Materials ♦ Characterization and Evaluation of Materials ♦ Electronics and Microelectronics, Instrumentation ♦ Solid State Physics and Spectroscopy Abstract The developments of quantum theory, solid-state physics, and computational methods make it feasible to understand properties of materials by means of calculation. In this work, five octahedron clusters were designed to study the wettability of Sn-based solder alloys, which are applied in modern electronic mounting and packaging. Then, relativistic DV-Xα calculation, which is a molecular orbital method based on Hartree-Fock-Dirac approximation, was carried out. Heavy atoms, such as Pb, Bi, Sn, and Sb, were included in our clusters, so relativistic effects were taken into account in the calculation. The electronic parameter, Bo, the orbital interaction between atoms, was obtained through a Mulliken analysis of electronic structure. The electronic structure mechanism for the wettability of Sn-based solder alloys on a Cu substrate was put forward based on the analysis of orbital interactions between atoms. We believe that the wettability of the Sn$_{x}$M$_{y}$ alloy would be improved only if orbital interactions between Sn atoms and Cu atoms are enforced because of the existence of the M element. The spreading and wetting behavior of Sn-based solder alloys were predicted and then explained by this quantum method on the basis of electronic structure theory. Predictions from analysis on calculation results were validated by wettability experiments and energy-dispersive x-ray (EDX) analysis. ISSN 03615235 Age Range 18 to 22 years ♦ above 22 year Educational Use Research Education Level UG and PG Learning Resource Type Article Publisher Date 2002-01-01 Publisher Place New York e-ISSN 1543186X Journal Journal of Electronic Materials Volume Number 31 Issue Number 3 Page Count 6 Starting Page 185 Ending Page 190