Study of PMMA recoveries on micrometric patterns replicated by nano-imprint lithography

We present a study of poly methyl methacrylate (PMMA) mechanical recoveries observed in the center of micro-scale structures replicated by nanoimprint lithography. Atomic force microscopy statistical analysis clearly reveals that the height and width of recoveries increase with the imprint force until a critical force above which they diminish to zero. This phenomenon, due to problems of PMMA resist transport, can be explained as a relaxation, directly after the demolding stage, of the elastic stresses stored by the resist during the imprint stage.