Thin-absorber extreme-ultraviolet lithography mask with light-shield border for full-field scanner: flatness and image placement change through mask process

摘要

When a thinner absorber mask is practically applied to thenextreme ultraviolet lithography for ultra large scale integration chip pro-nduction, it is inevitable to introduce an extreme ultraviolet u0001EUVu0002 lightnshield area to suppress leakage of the EUV light from adjacent exposurenshots. We believe that a light-shield border of the multilayer etching typenis a promising structure in terms of mask process flexibility for highernmask critical dimension accuracy. We evaluate the etching impact of thenabsorber and multilayer on the mask flatness and image placementnchange through the mask process of a thin absorber mask with a light-nshield border of the multilayer etching type structure. We clarify the re-nlation between mask flatness and mask image placement shift