Reliability of SnAgCu solder balls in packaging

Author

Erinc, M. ; Schreurs, P.J.G. ; Zhang, G.Q. ; Geers, M.G.D.

Author_Institution

Fac. Mech. Eng., Eindhoven Univ. of Technol., Netherlands

fYear

2005

fDate

18-20 April 2005

Firstpage

656

Lastpage

660

Abstract

SnAgCu ternary alloy is a commonly used lead-free alternative for SnPb solder. However, subjects regarding its thermo-mechanical response, microstructural evolution, material degradation and deformation mechanisms need further investigation. In BGA solder balls it is seen that deformation and damage propagation is strongly dependent on the microstructure in bulk as well as the bump/pad interfaces. The initial microstructure and material properties are collected through E-SEM observations and nano-indentation experiments. Critical interfaces under certain loading conditions are evaluated by inspecting fracture surfaces of SnAgCu solder paste reflowed on different substrates. These experimental results are supported by thermal cycling of commercial BGA packages with SnAgCu solder balls. A finite element model of a SnAgCu solder ball with Cu/Ni/Au metallization is made in 2-D. A cycling mechanical load is applied. Important microstructural constituents are also placed in the finite element model, and interfacial failure is analyzed using a cohesive zone model.

Keywords

ball grid arrays; deformation; finite element analysis; indentation; metallisation; reliability; scanning electron microscopy; silver alloys; solders; tin alloys; BGA package; BGA solder balls; Cu-Ni-Au; Cu/Ni/Au metallization; E-SEM; SnAgCu; SnAgCu solder balls; SnAgCu ternary alloy; SnPb solder; bump/pad interfaces; cohesive zone model; cycling mechanical load; damage propagation; deformation mechanism; finite element model; fracture surface; interfacial failure; material degradation; microstructural evolution; nanoindentation experiment; thermal cycling; thermomechanical response; Degradation; Environmentally friendly manufacturing techniques; Finite element methods; Gold; Lead; Material properties; Microstructure; Packaging; Surface cracks; Thermomechanical processes;

fLanguage

English

Publisher

ieee

Conference_Titel

Thermal, Mechanical and Multi-Physics Simulation and Experiments in Micro-Electronics and Micro-Systems, 2005. EuroSimE 2005. Proceedings of the 6th International Conference on

Print_ISBN

0-7803-9062-8

Type

conf

DOI

10.1109/ESIME.2005.1502883

Filename

1502883