Mechanics analysis of femtosecond laser-induced blisters produced in thermally grown oxide on Si(100)

Blister features produced by laser-induced delamination of silicon dioxide from silicon substrates were analyzed with thin-film buckling mechanics. These analyses revealed the role of the interaction between the material and the femtosecond (fs)-pulsed laser on blister formation. In particular, it was deduced that the magnitude of the compressive residual film stress within the irradiated region appeared to exceed the intrinsic residual stress obtained from wafer curvature techniques. This apparent increase in the compressive stress after fs-pulsed laser irradiation may be caused by a modification of the oxide, which resulted in a local rarefaction of the film. The results demonstrated important features of the interaction between materials and fs-pulsed laser, including the presence of subtle modification thresholds and the limited role of thermal effects.