To address the frequent clogging issues of BCl? mass flow controllers (MFCs) in semiconductor etching processes, this study proposes a comprehensive solution based on the chemical reaction mechanism of BCl? with trace water forming HCl/B?O?. The solution includes flow channel modification, full-path thermal insulation, material modification, and a standardized purge procedure. Experimental results demonstrate that the mean time between failures (MTBF) of the optimized MFC is significantly extended from approximately 3 months to 1-2 years. Regarding flow control accuracy, the pre-optimization system exhibited flow control errors up to ±15% within the 5-50 sccm range, accompanied by significant flow drift. After optimization, the flow control error is stably maintained within ≤5%, resulting in significantly improved etching rate stability. This research provides an effective engineering solution for enhancing the reliability of chlorine-based etching gas supply systems.