Deposition of uniform films on complex 3D objects by atomic layer deposition for plasma etch-resistant coatings

Atomic layer deposition (ALD) is a layer-by-layer technique for producing conformal, high-quality films, ideal for corrosion-resistant coatings on complex geometries. However, depositing thicker films on complex 3D objects presents challenges in maintaining effective precursor delivery across the surface. This paper describes the design and realization of a method to increase precursor concentration in the boundary layer near the complex object surface by introducing slitted baffles within the chamber. Using -OH surface coverage as a key indicator for assessing the extent of surface reactions, simulation is used to optimize the baffle number and shape. The optimal baffle design reduced surface film non-uniformity on the object surface from 35.46% to 5.75%, shortened the purge time from 12.8 to 9.7 s, and increased precursor utilization by 7%. Ideal Al₂O₃ films exhibited a fluorinated plasma etching rate of 1.11 nm min^-1, five times stronger than non-ideal films (5.19 nm min^-1), indicating superior plasma etching resistance.