Optical Properties of a Polyimide for Waveguide Applications in On-Chip Interconnects

Abstract

AbstractIn this work. we report on characterization methods and the optical properties of a polyimide (Ultradel 9020D). The prism coupling technique was used to couple light into polyimide thin films. The scattered light from the surface was imaged to determine the optical loss at different wavelengths. The coupling angle was used to find the refractive index of the films. The stability of the polymer in terms of refractive index and absorption losses was studied by heat treatment under nitrogen at elevated temperatures. No significant change was observed in the properties of the film at annealing temperatures below 200°C. The bulk and surface losses were separated and it was found that the waveguide losses were dominated by bulk losses. Temperature stability of the polymer was evaluated by annealing the polymer at 125°C for up to 30 hours. No significant changes were seen in the optical losses for these times.