Flexible stamp for nanoimprint lithography

The design, fabrication and performance of a flexible silicon stamp for homogenous large area nanoimprint lithography (NIL) are presented. The flexible stamp is fabricated by bulk semiconductor micro machining of a 4-inch silicon wafer and consists of thick anchor like imprint areas connected by membranes. The bending stiffness difference between the imprint areas and the membranes ensures that the deformation of the stamp during the imprint process mainly takes place in the membranes, leaving the imprint structures unaffected. By this design the strong demand to the parallelism between stamp and substrate in the imprint situation is decoupled from the pressing tool and the wafer quality. The stamp consist of 1562 imprint areas (1 mm × 1 mm) containing the patterns to be replicated. The imprinted patterns are characterized with respect to the imprint depth and the polymer residual layer thickness. It is found that within a 50 mm diameter the polymer residual layer thickness is 18.8 nm with a standard deviation of 6.6 nm.