Optimization of absorber and multilayer in EUV mask for 1D and 2D patterns

The oblique incidence of the illumination system in EUV lithography combined with relative thick absorber layer of EUV mask introduces many unique distortions on the image transfer between mask and wafer, most of these distortions are non-linear thus makes the enhancement of resolution more difficult. This paper focus on analysing the impacts of the absorber layer thickness, multilayer thickness and the light source morphology on the image. And improve the EUV lithography and imaging quality by co-optimization of these three parameters. Besides, the intrinsic features and rules of the impacts of absorber thickness on the imaging properties is revealed. And the different behaviour of 1D dense pattern and isolation pattern during the co-optimization is analysed and elucidated. This study provides a potential new direction for resolution enhancement technology.