Chien-Jen Tang^¹, Pei-Hsuan Tsai^¹, Yi Chen^¹, Ya-Chih Chou^¹, Wen-Yi Tai^2
¹Feng Chia University, Taichung, Taiwan
²Dah Young Vacuum Equipment Co., Ltd., Taichung, Taiwan
Achieving high thickness uniformity in large‑area optical coatings deposited by magnetron sputtering is increasingly challenging as substrate size and performance specifications continue to grow. Traditional correction‑mask designs typically rely on empirical deposition models and assumed source‑emission characteristics, limiting predictive capability and necessitating extensive experimental iteration. We present a unified, physics‑based framework that integrates plasma and magnetic‑field simulations, quantitative emission characterization, and correction‑mask–assisted deposition modeling for large‑area magnetron sputtering systems.
Using COMSOL Multiphysics, coupled magnetic‑field and plasma simulations provide spatially resolved sputtering‑yield and target‑erosion distributions. These results inform an angular‑emission model whose parameters are identified by inverse fitting to experimentally measured film‑thickness. Deposition is evaluated using a ray‑tracing‑based model that accounts for geometric visibility and mask transmission, with thickness accumulated over drum rotation to obtain full‑field thickness maps. The validated emission parameters and erosion profiles are then embedded in a rotating‑drum deposition workflow to design correction masks for plasma‑assisted reactive magnetron sputtering.
We validate the framework by depositing aluminum nitride, silicon dioxide, and multilayer antireflection coatings on glass substrates mounted on a rotating drum. Compared with uncorrected runs, the model‑derived correction mask significantly improves thickness uniformity and reduces average reflectance variation to < 0.77%, achieving ≤ 2% nonuniformity across a 5 cm × 8 cm optical area using a 6 cm × 18 cm target (along the 18 cm target span) and an 11 cm target-substrate distance. The proposed methodology provides a predictive, scalable route to large‑area optical‑coating fabrication while substantially reducing experimental iteration.