Abstract: The present disclosure generally relates to semiconductor structures and, more particularly, to mask structures and methods of manufacture. The method includes determining a plane through a frontside surface and a backside surface of a mask, each plane representing a flatness of the frontside surface and the backside surface, respectively; subtracting, using at least one computing device, a difference between the plane of the frontside surface and the plane of the backside surface to find a thickness variation; generating, using the at least one computing device, a fitting to fit the thickness variation; and subtracting, using the at least one computing device, the fitting from the thickness variation to generate a residual structure for collecting a residual flatness measurement.

Abstract: The present disclosure generally relates to semiconductor structures and, more particularly, to mask structures and methods of manufacture. The method includes determining a plane through a frontside surface and a backside surface of a mask, each plane representing a flatness of the frontside surface and the backside surface, respectively; subtracting, using at least one computing device, a difference between the plane of the frontside surface and the plane of the backside surface to find a thickness variation; generating, using the at least one computing device, a fitting to fit the thickness variation; and subtracting, using the at least one computing device, the fitting from the thickness variation to generate a residual structure for collecting a residual flatness measurement.

Abstract: The present disclosure relates to semiconductor structures and, more particularly, to modified surfaces of extreme ultraviolet lithography photomasks and methods of manufacture. The structure includes a reflective surface having a patterned design, and a black border region at edges of the patterned design. The black border region includes a modified surface morphology to direct light away from reaching a subsequent mirror.

Abstract: The present disclosure relates to semiconductor structures and, more particularly, to modified surfaces of extreme ultraviolet lithography photomasks and methods of manufacture. The structure includes a reflective surface having a patterned design, and a black border region at edges of the patterned design. The black border region includes a modified surface morphology to direct light away from reaching a subsequent mirror.