The optimized oxygen inductively coupled plasma etching parameters are systematically studied to fabricate Poly (methyl-methacrylate-glycidly-methacrylate) inverse ridge waveguide with smooth vertical features. The etch rate, surface roughness and vertical profile are characterized by atomic force microscopy and scanning electron microscopy. The optimized etching parameters are found to be 400-W antenna-RF power, 30-W radio frequency (RF) bias power, 1-Pa-chamber pressure, and 40-sccm be O2-flow
