Passive compliant wafer stage for single-step nano-imprint lithography

Nano-imprint lithography, which has the advantages of simplicity, low cost, high replication fidelity and relatively high throughput, requires surface contact between a template with nano patterns and a wafer that transfers the patterns. This article presents the wafer stage for single-step nano-imprint lithography. The wafer stage has a six degree-of-freedom compliant mechanism for complete contact between the surface of the template and the surface of the wafer. The compliant mechanism consists of an inner mechanism for in-plane motion and an outer mechanism for out-of-plane motion. The inner and outer mechanisms have symmetric flexures, which were machined monolithically, onto each plane to cope with thermal deformation. The wafer stage, which was designed to satisfy stiffness requirements, is analyzed with the aid of a dynamic model for a flexure mechanism and a finite element method. Experiments were conducted on the wafer stage in a nano-imprint machine, and nano patterns with linewidths of 100 and 86nm were transferred successfully. This result verifies that the proposed wafer stage can be used in nano-imprint lithography.