Patent ID: 10768521

Abstract:
An extreme ultraviolet (EUV) mask including an absorber structure is disclosed. The absorber structure may include at least one slanted and/or concave sidewall. The absorber structure may include a sidewall including a step. A method of forming an absorber for an EUV mask is disclosed. The method may include etching an absorber layer using a mask to form an absorber structure having a sidewall wherein an outer edge of the top surface of the sidewall is closer to a central vertical axis of the absorber structure than an outer edge of the bottom surface of the sidewall. The method may include performing additional etching steps to form a step along the sidewall of the absorber structure. The etching may include combinations of anisotropic etching in different directions, and/or isotropic etching. The method may include etching an absorber layer including multiple absorber layers having different material properties on the ML reflector.