Flow-field-driven control of coating uniformity in fowlp soft-bake chambers
摘要
Fan-out wafer-level packaging (FOWLP) requires precise flow-field control during the soft bake process to ensure coating uniformity and wafer yield. This study investigates the direct correlation between chamber hydrodynamics and photoresist film formation by combining computational fluid dynamics (CFD) simulations with experimental wafer fabrication. Chamber models with different inlet geometries—hole and slit—and the presence of baffles were analyzed using the realizable k–ε turbulence model. Experiments on 300 mm wafers produced ∼45 µm films, whose uniformity was evaluated through 3D contour mapping and six-sigma indices, including Cp, Cpk, Z-score, and DPMO. Furthermore, Pearson correlation and linear regression demonstrated statistically significant relationships (r > 0.9, p < 0.05) between flow uniformity and coating quality. Through this study, results revealed that the slit-with-baffle configuration achieved the most stable pressure and velocity distribution and superior process capability compared to other chambers. This work provides quantitative evidence that flow distribution strongly influences coating uniformity and offers practical design guidelines for next-generation wafer manufacturing.