Pattern-induced non-uniformity of residual layers in nanoimprint lithography

Abstract

Imprint processes into thin layers can be described by the equations of squeezed flow. In case they account, in a modified form, for the filling of the stamp cavities during the imprint process, they predict significant non-uniformity of the residual layer in areas with different pattern densities. This phenomenon is even intensified by the different imprint velocities of structures with different pattern sizes. The residual layers achieved and their uniformity strongly depend on the pattern sizes and cavity sizes of the stamp. Non-uniformities are lower under cavity filling on the cost of the absolute value of the residual height. In some cases the layout of a device can in parts be adapted to the imprint process by segmentation of larger structures without changing the device functionality. When the segmentation is designed in a way, that its pattern density is similar to the major pattern density within the functional area of the device thin and uniform residual layers are achieved after very short imprint times.