Title: Determination of Young's modulus and yield strength of porous low-k dielectric films by nanoindentation under complete consideration of the substrate influence

Authors: M. Herrmann, F. Richter

Addresses: Institute of Physics, Solid State Physics, Chemnitz University of Technology, 09107 Chemnitz, Germany. ' Institute of Physics, Solid State Physics, Chemnitz University of Technology, 09107 Chemnitz, Germany

Abstract: The capabilities of the |effective indenter method| with respect to the characterisation of porous xerogel thin films have been investigated using samples with porosities ranging from 43% to 57%. Young|s modulus of the samples was decreasing from 2.67 GPa to 0.83 GPa with growing porosity. Yield strength was determined using spherical indentation data. With a larger indenter (R = 48 μm) the |effective indenter method| could be directly applied while for a smaller one (R = 4.2 μm) the |effective indenter extrapolation method| had to be utilised to account for the larger amount of plastic deformation. Both approaches delivered the same yield strength decreasing from (140 ± 5) MPa to (75 ± 3) MPa with increasing porosity.

Keywords: Young|s modulus; yield strength; porous dielectric films; low-k dielectric films; substrate influence; indentation; nanoindentation; effectively shaped indenter; porous materials; plastic deformation.

DOI: 10.1504/IJSURFSE.2009.024362

International Journal of Surface Science and Engineering, 2009 Vol.3 No.1/2, pp.64 - 85

Available online: 01 Apr 2009 *

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