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

Abstract

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.

Fabrication of Si photonic waveguides by electron beam lithography using improved proximity effect correction

“…In our previous report, we reported the fabrication and measurement of Si-waveguides with dose modulation PEC for a 700 nm thick ZEP mask. 18) Conventional EDD representation was utilized, where beam energy distribution is simulated by the Monte-Carlo scattering simulation technique. 19) Simulation was performed using commercial software.…”