Real-Time Compensation of Simultaneous Errors Induced by Optical Phase Difference and Substrate Motion in Scanning Beam Laser Interference Lithography System

Recent advances in display electronics, and micro- and nanophotonics have prompted development of novel nanofabrication technologies that enable production of high-fidelity periodic patterns over a large-area substrate. Scanning beam laser interference lithography (SBLIL) is a high-speed manufacturing process of such high-precision nanogratings; however, the precision of the nanopatterns produced by the SBLIL is negatively affected by several factors, including mechanical and optical phase jitters. Previous studies have focused on pattern production, but little research has been conducted on the error correction. In this paper, we propose a design methodology for comprehensive and real-time control of substrate motion and optical path difference in SBLIL process. We derived equations that relate SBLIL error sources to control inputs, and implemented the control strategy through acousto optical modulation and piezo electric actuation. The develop scheme was applied to the SBLIL process, and validated by presenting improved nano-pattern uniformity.