Advances in Fabrication Technology of Fine Metal Masks for OLED Material Deposition: Research Status and Future Development Directions

Fine metal mask (FMM) is the essential consumable for high-precision pixel patterning in OLED vacuum evaporation, yet its fabrication remains a critical bottleneck for high-resolution displays. This review systematically summarizes three manufacturing routes for Invar-alloy FMMs: chemical etching method (CEM), electroforming method (EFM), and laser processing method (LPM). CEM is currently the only mature method for large-scale production because of its high throughput, but the coupled effects of chemical reaction, mass transfer, and double-sided etching make it susceptible to unetched and partially etched holes, leading to low yield, material waste, and economic loss. EFM offers potential for finer structures, but alloy composition control, internal stress, cost, and insufficient evaporation-performance verification still limit its practical application. LPM, especially ultrafast laser machining, can fabricate high-quality microholes in Invar foils and has demonstrated pixel densities up to 3000 PPI; however, processing millions of holes one by one remains too inefficient for full-mask mass production. Based on this comparison, we propose a hybrid “CEM + laser repair” route, in which CEM provides high-throughput primary fabrication and LPM is used for localized reprocessing of defective holes. Four key issues for enabling this route are identified: precise defect localization, laser-parameter optimization, layered modeling of defective-hole geometries, and scanning-trajectory design. This review clarifies the present status and limitations of FMM fabrication technologies and highlights laser repair of defective FMMs produced by CEM as a promising strategy for improving manufacturing yield, reducing waste, and supporting sustainable production of high-resolution OLED displays.