Open Access

ARTICLE

On the First-principles Density Functional Theory Calculation of Electromigration Resistance Ability for Sn-based Intermetallic Compounds

by Wen-Hwa Chen¹, Ching-Feng Yu¹, Hsien-Chie Cheng²

1 Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu, Taiwan, ROC.
2 Corresponding author.
3 Department of Aerospace and Systems Engineering Feng Chia University, Taichung, Taiwan, ROC.

Computer Modeling in Engineering & Sciences 2014, 100(2), 119-131. https://doi.org/10.3970/cmes.2014.100.119

Abstract

The aim of the study is to investigate the interactions between Sn adatoms in a solder bump and three typical Sn-based intermetallic compounds (IMCs) surface, i.e., Cu₃Sn, Cu₆Sn₅, and Ni₃Sn₄, at the atomistic scale. The adsorption energy, average bond length, and bond population of the Sn/Cu₃Sn, Sn/Cu₆Sn₅,and Sn/Ni₃Sn₄ systems are calculated through the first-principles density functional theory (DFT) calculation to investigate how the Sn adatoms influence the IMC surface. The calculated results show that the Sn atoms on the Cu₃Sn (0 0 1) surface hold the largest adsorption energy, average bond length and bond population, implying that the Cu₃Sn (0 0 1) surface is the most stable surface for Sn adatoms. Moreover, the electromigration resistance ability of three typical Snbased IMCs can be further identified according to the nominal the adsorption energy, average bond length, and bond population, which are estimated through averaging the adsorption energy, average bond length, and bond population for the Cu₃Sn, Cu₆Sn₅ and Ni₃Sn₄ IMCs at seven crystal surfaces, i.e., (1 0 0), (0 1 0), (0 0 1), (1 1 0), (1 0 1), (0 1 1) and (1 1 1). The results reveal that Cu₃Sn holds the best electromigration resistance ability, followed by Ni₃Sn₄ and Cu₆Sn₅.

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Keywords

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