A method of gap control based on the principle of equal thickness interference for HARNS fabrication

摘要

The gap, which affects pattern resolution, especially during the nanofabrication process by X-ray lithography, is a very notable problem researchers pay much attention to. Until now, there still has not been a simple, economical method to control a small and uniform gap. In this paper, a method based on the principle of equal-thickness interference has been proposed. Firstly, an accessorial structure with the height of the gap is fabricated on the mask support to achieve a small gap. Then the principle of equal-thickness interference is applied to adjust the parallelism to ensure a uniform gap between the mask and the wafer. This method is not only simple and low cost, but also can control a small and uniform gap accurately, so that the quality of pattern replication during X-ray lithography can be improved and the mask can also be protected. Based on this method, a small and uniform gap is realized and high aspect ratio nanostructures (HARNS) are fabricated.