An interference lithography splicing dose uniformity optimization method based on Gaussian fitting of light beams

Abstract

This invention proposes a method for optimizing the dose uniformity of laser interference lithography stitching based on Gaussian beam fitting, belonging to the field of ultra-precision micro / nano manufacturing technology. Addressing the stitching unevenness problem caused by beam distortion and finite boundary effects in large-area stepping interference lithography, this invention acquires actual interference light field images and performs global two-dimensional Gaussian fitting to accurately extract spot feature parameters. Based on this, a dose accumulation model under finite dot matrix scanning is constructed, and the optimal two-dimensional step displacement that can compensate for local interference troughs and macroscopic attenuation envelope is calculated through optimization. Simultaneously, an exposure dose constraint mechanism is introduced to limit the cumulative total light intensity within the development threshold range to prevent photoresist overexposure degradation caused by high overlap. Finally, the optimal parameters are output and used to control the positioning stage for precise exposure. This invention effectively overcomes the obvious gaps and energy distortion caused by traditional fixed-spacing stitching, achieving high-quality, seamless stitching manufacturing of large-area holographic gratings.

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