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Quantitative Determination of the Mechanical Stresses in BEoL Films and Structures on Si Wafers with Sub-micron Spatial Resolution by fibDAC

  • Sven Rzepka (a1), Dietmar Vogel (a1), Ellen Auerswald (a1) and Bernd Michel (a1)

Abstract

The fibDAC stress analysis method, a new tool for local stress measurement, has been applied to patterned BEoL structures after being validated at complete films by established industrial methods like wafer bow measurement. The new tool uses focused ion beam (FIB) to mill a narrow trench of down to 30 nm width into the surface of the structure under investigation to trigger stress relief in its vicinity. Capturing the corresponding deformation by high resolution SEM micrographs and local digital image correlation, the original stress can be determined by simulating the stress relief process by automated finite element analyses. Simultaneously, the extraction of key material parameters of the film like Young’s modulus and Poisson’s ratio is possible.

The spatial resolution of the fibDAC stress analysis method is 1 μm and better. It has been demonstrated at arrays of BEoL interconnects. The magnitude of the local stresses inside the metal traces has been shown to be substantially different to those occurring in the dielectrics between the lines. Such a spatial resolution clearly outperforms all established industrial methods.

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1. Freund, L.B., Suresh, S.; Film stress and substrate curvature, in Thin Film Materials, Cambridge University Press, 2003, pp. 86153.
2. Geisler, H. et al. ;Temperature-dependent stress measurements at inlaid copper interconnect lines, in Stress-Induced Phenomena in Metallization, AIP Conference Proceedings, Vol. 817, Meville, 2006, pp. 277287.
3. Neels, A., Dommann, A.; Advanced in- and out-off plane high resolution X-ray strain analysis on MEMS, Techn. Proc. NSTI Nanotech; Anaheim, 2010, Vol. 2, pp. 182185.
4. Song, Xu et al. ; Experimental/modeling study of residual stress in Al/SiCp bent bars by synchrotron XRD and slitting eigenstrain methods, Materials Science Forum, Vols. 571-572, 2008, pp. 277-282.
5. Wilkinson, A.J., Meaden, G., Dingley, D.J.; High-resolution elastic strain measurement from electron backscatter diffraction patterns: new level of sensitivity, Ultramicroscopy, Vol. 106, 2006, pp. 307313.
6. Sabaté, N., et al. ; Measurement of residual stresses in micromachined structures in a micro region, Appl. Physics Letters 88, 071910, 2006.
7. Vogel, D. et al. ; Localized stress measurements – a new approach covering needs for advanced micro and nanoscale system development, Proc.. of ECTC 2007, Reno, pp. 1490–1497.
8. Digital Image Correlation VEDDAC 5.1-User’s Manual, Chemnitzer Werkstoffmechanik GmbH, Chemnitz, Germany, 2011
9. Bressan, J.D., Tramontin, A., Rosa, C.: Modeling of nanoindentation of bulk and thin film by finite element method; Wear, Vol. 258, 2005, pp. 115–22
10. OptiSLangTM 3.2, User’s Manual; Dynardo GmbH, Weimar, Dec. 2011

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