Fabrication of Low CTE Metal Masks by the Invar Fe-Ni Alloy Electroforming Process for Large and Fine Pitch OLED Displays

Low CTE and fine pitch metal masks were fabricated by the invar Fe-Ni alloy electroforming process. The invar Fe-Ni alloy metal masks obtained had finer 10µm x 30µm rectangular open areas with a thickness of about 10µm. The CTE of the electroformed Fe-Ni alloy fine pitch metal mask was 10ppm/K for the as-deposited mask and higher than the melted invar alloys. On the other hand, the CTE of the mask with annealing at 873K exhibited approximately 3ppm/K and was 4 times less than that of conventional electroformed Ni and Ni-Co alloys. The electroformed invar Fe-Ni alloy metal masks obtained are anticipated for use in the vapor deposition process for large and fine pitch OLED displays.