A force-decoupled compound parallel alignment stage for nanoimprint lithography

This paper presents the development of a force-decoupled compound parallel alignment stage for nanoimprint lithography. Parallel alignment stage is a critical component of nanoimprint machine to implement the uniform surface contact between the template with predefined micro/nano patterns and the substrate that accepts the patterns. A combination of a high-stiffness spherical air bearing and a multi degree-of-freedom flexure-based mechanism is adopted in the parallel alignment stage. Apart from the parallel alignment function, the proposed stage can also endure a large imprinting force (more than 1000 N) but does not cause any damage to the delicate flexure-based mechanism. The stage performance is evaluated to satisfy the alignment requirement through the theoretical modeling and finite element analysis. Experiments are conducted on the parallel alignment stage to verify its performance on the transferred grating patterns with linewidth of 2.5 μm. This result demonstrates that the proposed approach can enhance the load capacity of the parallel alignment stage without degrading its alignment accuracy for nanoimprint lithography.