A nanoindentation apparatus is used to measure adhesion strength of a hard,
thin film to a soft substrate. A variably increasing load is applied to
the indenter tip. The indenter tip penetrates into the thin film at a
first penetration rate and causes the thin film to sink into the substrate
thus causing a tensile stress at the film substrate interface. At a
critical value of the applied load, the stress at the interface exceeds
the delamination value, and the thin film partially delaminates from the
substrate. This causes the indenter tip to sink into the softer substrate
at a sudden second, higher penetration rate. A sensor detects the applied
load and the indenter tip penetration depth at this point. A computer
flags the critical value of the applied load that corresponds to the
increased penetration depth rate at the point of delamination of the film.
The computer then calculates the critical stress required for delamination
and the adhesion strength between the film and the substrate from the
critical value of the applied load. The depth sensing indentation
technique measurement may be carried out on a thin film integrated test
element so as not to damage the rest of the thin film. The method allows
non-destructive in-situ adhesion strength measurements for thin films and
microelectronic devices.