A Compact Analytic Model of the Strain Field Induced by Through Silicon Vias

Sun-Rong Jan, Tien-Pei Chou, Che-Yu Yeh, C. W. Liu, R. V. Goldstein

IEEE Transactions on Electron Devices · 2012 · 22 citations · 15 references

Concepts

Abstract

The thermoelastic strains are induced by through silicon vias due to the difference of thermal expansion coefficients between the copper ( ~ 18 ppm / °C) and silicon ( ~ 2.8 ppm /°C) when the structures are exposed to a thermal ramp in the process flow. A compact analytic model (Bessel function) of the strain field is obtained using Kane-Mindlin theory, and has a good agreement with the finite-element simulations. The elastic strains in the silicon in the radial direction and angular direction are tensile and compressive, respectively. The linear superposition of the analytic model of a single via can be used in the multi-via configuration. Due to the interaction of vias, the slightly larger errors of strain occur between the two close vias when the linear superposition is used.

References

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