Abstract:
This chapter is a review of a laser-based adhesion testing experimental protocol
to characterize the fracture toughness of the interface between a thin film and a
substrate using a dynamic non-contact loading technique. Controlled dynamic
delamination of thin film patterns from substrates is achieved using laser-induced
stress pulses. The specimen geometry consists of a thin film pattern with an area of
weak adhesion sandwiched between the thin film and substrate. A high-amplitude
stress pulse generated on the backside of the substrate fails the weak adhesion
region creating a pre-crack at the interface. The kinetic energy accumulated in
the de-bonded portion of the thin film is subsequently channeled into the thin
film-substrate interface leading to a controlled dynamic interfacial crack propagation.
The thin film-substrate interface fracture toughness is determined by equating
the kinetic energy to the fracture energy required for film delamination. This
chapter also includes detailed parametric studies that help in understanding the
effect of various experimental parameters on the kinetic energy available for interfacial
dynamic crack propagation followed with a brief overview of numerical
simulation that validates the experimental protocol.
