Creep Properties of Sn-1.0Ag-0.5Cu Lead-Free Solder with Ni Addition

• Published in: Journal of electronic materials Vol. 40; no. 3; pp. 344 - 354
• Main Authors: Che, F. X., Zhu, W. H., Poh, Edith S. W., Zhang, X. R., Zhang, Xiaowu, Chai, T. C., Gao, S.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.03.2011; Springer; Springer Nature B.V
• Subjects: Applied sciences; Arrays; Brazing. Soldering; Characterization and Evaluation of Materials; Chemistry and Materials Science; Constitutive relationships; Creep (materials); Cross-disciplinary physics: materials science; rheology; Deformation, plasticity, and creep; Electronics and Microelectronics; Exact sciences and technology; Finite element analysis; Instrumentation; Joining, thermal cutting: metallurgical aspects; Lead free solders; Materials creep; Materials Science; Mathematical models; Metals. Metallurgy; Nickel; Optical and Electronic Materials; Physics; Solders; Solid State Physics; Strain; Stresses; Tin; Treatment of materials and its effects on microstructure and properties; Sn-Ag-Cu alloy; finite-element analysis; Creep; constitutive model; lead-free solder; Ni addition; Constitutive equation; Creep test; Creep rate; Review; BGA technology; Finite element method; Nickel addition; Lead free solder; Stress effects; Activation energy; Power law; Temperature dependence; Strain energy; Mechanical properties; Energy density; Tension test; Experimental result; Soldered joint; Numerical simulation; Software
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-011-1510-7

In this work, tensile creep tests for Sn-1.0Ag-0.5Cu-0.02Ni solder have been conducted at various temperatures and stress levels to determine its creep properties. The effects of stress level and temperature on creep strain rate were investigated. Creep constitutive models (such as the simple power-law model, hyperbolic sine model, double power-law model, and exponential model) have been reviewed, and the material constants of each model have been determined based on experimental results. The stress exponent and creep activation energy have been studied and compared with other researchers’ results. These four creep constitutive models established in this paper were then implemented into a user-defined subroutine in the ANSYS™ finite-element analysis software to investigate the creep behavior of Sn-1.0Ag-0.5Cu-0.02Ni solder joints of thin fine-pitch ball grid array (TFBGA) packages for the purpose of model comparison and application. Similar simulation results of creep strain and creep strain energy density were achieved when using the different creep constitutive models, indicating that the creep models are consistent and accurate.