Loss reduction of Si optical waveguides by beam step-size fracturing technique in electron beam lithography

摘要

Electron beam lithography shot-pattern design technologies and a dedicated algorithm for patterning and miniaturization of the exposure area were investigated. Beam step-size fracturing was used to optimize the fill pattern at the designed pattern edges, and propagation loss was reduced for a 500-nm-wide Si wire waveguide with a 30° tilt angle from 4.7 to 3.0 dB/cm using a conventional process. Furthermore, proximity effect correction technology allowed the integration of different trench widths for a 5 μm spot-size converter and 1 μm Si wire waveguide. The propagation loss was reduced to 2.1 dB/cm due to optimization of the dose density for each exposure area, and runtime was reduced to less than half.