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The thermo-mechanical integration of polymer films requires a precise knowledge of material properties. Nanoindentation is a widely used testing method for the determination of material properties of thin films such as Young’s modulus and the hardness. An important assumption in the analysis of the indentation is that the indented medium is a semi-infinite plane or half space, i.e., it has an “infinite thickness.” In nanoindentation the analyzed material is often a thin film that is deposited on a substrate. If the modulus ratio is small, (soft film on hard substrate) and the penetration depth is small too, then the Hertzian assumption does not hold. We investigate this situation with spherical and conical indentation. Measurement results are shown using spherical indentation on a visco-elastic thin polymer film and a full visco-elastic characterization is presented.

In microelectronic industry, thin polymer layers are one of the more commonly used product constituents. Examples are glue layers, coatings, and dielectric layers. The thicknesses of these films vary from a few tens of nanometers to over a hundred micrometers. Since at film thicknesses below 100nm the thermal and mechanical properties start to deviate from those in the bulk, adequate characterization techniques are required. In the present paper we will report the results of an extensive literature search on the state-of-the-art of thermo-mechanical thin film characterization methods, such as the substrate curvature test, nanoindentation technique, bulge test, and impulsive stimulated thermal scattering.