单模硅波导与光栅耦合器在干法刻蚀中的系统性工艺偏差分析OA

This study aims to systematically investigate the mapping relationship between wafer-level uni-formity in lithography and dry etching processes,and the physical morphology and optical performance of silicon photonic passive devices on an 8-inch silicon-on-insulator(SOI)platform.The experiments were conducted on a 220 nm top-silicon SOI platform.A two-step full-process fabrication flow was implement-ed using deep ultraviolet(DUV)lithography and inductively coupled plasma reactive ion etching(ICP-RIE).The process included the fabrication of grating couplers with a 70 nm shallow etch and single-mode straight waveguides with a 220 nm full etch.The physical dimensions and optical propagation loss were systematically characterized across five 8-inch wafers using atomic force microscopy(AFM),critical-di-mension scanning electron microscopy(CD-SEM),and an automated optical probe station.A certain de-gree of wafer-to-wafer stability was observed among the five wafers.Statistical analysis based on standard deviation,semi-range,and their relative variations indicated that the average etch depth and average line-width remained within relatively stable ranges across different wafers.However,within-wafer(WIW)ra-dial process variations were observed.The reduction in microscopic dimensions in the edge region,togeth-er with possible sidewall morphology degradation,may alter the optical mode distribution and increase sidewall scattering loss.As a result,the propagation loss of the single-mode waveguides exhibited an in-creasing trend from the wafer center toward the edge.These results suggest that macro-loading effects and lateral etching behavior during dry etching of large-diameter wafers are important factors influencing within-wafer performance consistency in silicon photonic chips.The findings provide experimental evidence and process optimization guidance for future optical proximity correction(OPC),etching recipe optimization,and wafer-level yield improvement on 8-inch SOI platforms.