EUV mask blank defect mitigation

摘要

A solution for mitigating the effects of EUV substrate surface defects is disclosed. In one embodiment, a layer of polyimide material is formed upon a mask substrate surface, resulting in a substantially defect free surface adjacent to which a reflective multilayer may be positioned for EUV lithography. To reduce the possibility of polyimide outgassing and resultant added roughness to adjacently positioned layers, the layer of polyimide may be cured in a vacuum at an elevated temperature before other layers are adjacently positioned.