Effective intensity distributions used for direct laser interference exposure

This paper presents a method to obtain periodic structures with different feature shapes using direct laser interference lithography. In the method, the desired structures are produced by controlling the effective intensity distributions of interference patterns during the exposure process. The effective intensity distributions are adjusted by changing the exposure beam intensity based on the material modification thresholds. In the simulations and experiments, different exposure intensities were used to study the interactions between the effective intensity distributions and the materials, and direct four- and six-beam laser interference lithography systems were set up to pattern silicon wafers. The shapes and sizes of the fabricated surface structures changed with the effective intensities. The experimental results are in accordance with the theoretical models and simulations.