Failure mechanisms and optimum design for electroplated copper Through-Silicon Vias (TSV)

Through-silicon vias (TSVs) have garnered a lot of interest in recent years because TSV is a key enabling technology for three dimensional (3D) integrated circuit (IC) stacking, silicon interposer technology, and advanced wafer level packaging (WLP). There has been significant effort in TSV fabricat...

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Bibliographic Details
Published in2009 59th Electronic Components and Technology Conference pp. 624 - 629
Main Authors Xi Liu, Qiao Chen, Dixit, P., Chatterjee, R., Tummala, R.R., Sitaraman, S.K.
Format Conference Proceeding
LanguageEnglish
Published IEEE 01.05.2009
Subjects
Copper
Deformable models
Failure analysis
Finite element methods
Finite-Element Modeling
Integrated circuit technology
Performance analysis
Thermal stresses
Thermo-mechanical Reliability
Thermomechanical processes
Through Silicon Via
Through-silicon vias
X-ray scattering
XRD measurements
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Summary:Through-silicon vias (TSVs) have garnered a lot of interest in recent years because TSV is a key enabling technology for three dimensional (3D) integrated circuit (IC) stacking, silicon interposer technology, and advanced wafer level packaging (WLP). There has been significant effort in TSV fabrication and electrical design. However, considerably less work has been done on thermo-mechanical analysis and mechanical design of these structures. Due to the high coefficient of thermal expansion (CTE) mismatch between Si and the conducting material in the vias, thermo-mechanical reliability is a major concern. This paper uses finite-element (FE) models and X-ray diffraction (XRD) experiments for the thermo-mechanical analysis of TSVs. Two-dimensional thermo-mechanical finite-element models have been built to analyze the stress/strain distribution in the TSV structures, and the models show that large stress gradients and plastic deformation exist near the corner of electroplated Cu pads. The stress results from the finite-element models have been compared against XRD experimental data. A fracture mechanics analysis has also been performed, and the fracture analysis shows that Cu/SiO 2 interfacial cracks and SiO 2 cohesive cracks are more likely to initiate and propagate at those corner locations.
ISBN:1424444756
9781424444755
ISSN:0569-5503
2377-5726
DOI:10.1109/ECTC.2009.5074078