Adhesion of polymer thin-films and patterned lines

The adhesion of interfaces in thin-film structures containing ductile polymer blanket films and patterned lines is reported. The intent of the study was to demonstrate that both the film thickness and the aspect ratio of patterned lines have a significant effect on the interfacial fracture energy of interfaces adjacent to the ductile polymer. In particular, there is currently limited understanding of the effect of dimensional constraint in the plane of the film on local plasticity and associated interfacial fracture energies. Accordingly, the interfacial adhesion of patterned structures containing arrays of polymer/SiO2 lines with varying aspect ratios was investigated. Macroscopic adhesion values were determined by measuring the critical strain energy release rate, Gc, for debonding of the patterned interface. The yield properties of the polymer films as a function of film thickness was also investigated. Decreasing aspect ratio of the polymer lines was found to significantly increase interface fracture energy and is rationalized in terms of the effect of stress state on the extent of plastic deformation in the polymer line.