Dependencies of bias tables to pattern density, critical dimension, global coordinates and pattern orientation for nanoimprint master manufacturing for the 200 mm wafer scale SmartNIL process

In this paper the bias table models and rules-based correction strategies for the wafer scale nanoimprint lithography (NIL) technology are addressed using complete Scanning Electron Microscopy (SEM) characterizations. This replication technology is known to induce Critical Dimension (CD) variations between the master and the imprint, due to polymer shrinkage, soft stamp deformation or thermal expansion. The bias between the former and final object follows peculiar rules which are specific to this process. To emphasis these singularities, Critical Dimension (CD) uniformity analyses are performed onto 200 mm wafers imprinted with the HERCULES® NIL equipment platform. Dedicated masters were manufactured which have horizontal and vertical line arrays, with local densities ranging from 0.1 to 0.9, with a minimum CD of 250 nm. The silicon masters were manufactured with 248 optical lithography and dry etching and treated with an anti-sticking layer from Arkema. CD measurements were made for the master and the replicates on 48 well selected features to build an interpolation. The data revealed that the CD evolutions can be modelled by polynomial functions with respect to the density, the CD and the orientation (vertical or horizontal) on the GDS. Finally the focus is made on the dependence of the design rules with respect to the position on the master, and it opens the discussion on the strategies for efficient wafer scale corrections for the nanoimprint soft stamp technologies.