Abstract: An EUV mask (10, 309) includes an opening (26) that helps to attenuate and phase shift extreme ultraviolet radiation using a subtractive rather than additive method. A first embedded layer (20) and a second embedded layer (21) may be provided between a lower multilayer reflective stack (14) and an upper multilayer reflective stack (22) to ensure an appropriate and accurate depth of the opening (26), while allowing for defect inspection of the EUV mask (10, 309) and optional defect repair. An optional ARC layer (400) may be deposited in region (28) to reduce the amount of reflection within dark region (28). Alternately, a single embedded layer of hafnium oxide, zirconium oxide, tantalum silicon oxide, tantalum oxide, or the like, may be used in place of embedded layers (20, 21). Optimal thicknesses and locations of the various layers are described.

Abstract: Methods and apparatus are provided for extreme ultraviolet phase shift masks. The apparatus comprises a substrate, a reflectance region, and an attenuating phase shifter. The reflectance region overlies the substrate. The attenuating phase shifter overlies the reflectance region. The attenuating phase shifter includes a plurality of openings that expose portions of the reflectance region. The attenuating phase shifter attenuates radiation through a combination of absorption and destructive interference. The method comprises projecting radiation having a wavelength less than 40 nanometers towards a mask having a plurality of openings through an attenuating phase shifter. The plurality of openings expose a reflectance region in the mask. The attenuating phase shifter is less than 700 angstroms thick. Radiation impinging on the reflectance region exposed by said plurality of openings is reflected whereas radiation impinging on the attenuating phase shifter is attenuated and shifted in phase.