Monolithic design of a compliant template orientation stage for step imprint lithography

Abstract

The parallel surface contact between a template and a wafer is of critical importance for pattern fidelity in step imprint lithography. The passive compliant stage, which has a much simpler structure than an active control one, is an effective orientation-adjusting mechanism. For a perfect passive compliant stage, the orientation-adjusting process should bring about the smallest possible additional lateral motion to maintain the overlay precision. In the present paper, based on the analysis of a compliant wafer stage and the influence of the rotation axis on position shift, a monolithic template orientation stage with four groups of passive compliant mechanisms is proposed to satisfy the above requirements. This compliant template orientation stage can be regarded as two four-bar linkages that interfere with each other, with the connecting line of two flexible hinges in each group passing through the centre of the template, ensuring that the rotation axis is located in the centre of the template during the whole orientation-adjusting process. The performance of the designed compliant template orientation stage is researched using the finite element analysis method and experiments. The results indicate that this compliant template stage can ensure the parallel surface contact between a template and a wafer while minimizing relative lateral motion during the imprinting process.