In nanoimprint lithography (NIL), one of the key points to be addressed is the printing uniformity on large area. During the process, the silicon mold undergoes significant mechanical stress of different kinds (tension, compression, flexion, and torsion). These stresses are function of the mold design and appear under the concurrent influence of both the applied pressure on the backside of the mold and an opposite force due to the polymer viscoelastic behavior. This translates into non-negligible deformations within patterned or unpatterned zones. This is a major issue because it causes nonuniformity of the printing, mold pattern break and degradation of the polymer surface. In this article, we demonstrate that during the imprint process mold deformations really occur at the local scale of the patterns but also at a larger scale.

Articles you may be interested inViscosity measurement of nanoimprint lithography resists with a rheological nanoindenter Effect of fluoroalkyl substituents on the reactions of alkylchlorosilanes with mold surfaces for nanoimprint lithography J.Polymer selection and critical dimension control across the wafer are key parameters for the nanoimprint lithography technique. This nanotechnology requires polymers having a low glass transition temperature T g combined with a good etch resistance. In this work, three different polymers have been evaluated. The influence of the temperature and pressing time is analyzed to clarify the correlation between polymer behavior and printing uniformity as a function of the pattern density. Measurements of the polymer residual thickness show that the printing uniformity is strongly correlated with the thermal properties of the polymer.