Study of High Aspect Ratio SiN WG Etch in Silicon Photonics

The rapid development of artificial intelligence (AI) has greatly changed modern society. Silicon Photonics have made it a prominent platform for photonic integration. Optical Waveguides function as essential light-guiding structures, which directly influence optical loss. This work addresses the manufacturing challenges of high aspect ratio over 10 silicon nitride (Si3N4, SiN) WGs. We provide a mature etching methodology based on Lam’s Kiyo^® series platform that systematically optimizes processes to handle critical challenges such as aspect ratio-dependent etching effects, pattern loading effects, and worse surface roughness. Finally, we get CD uniformity within 3%, SWA loading within 1°, and LWR within 4 nm.