Thermomechanical changes of EUV mask and absorber dependency

Abstract

Thermal and structural deformations of extreme ultraviolet lithography (EUVL) masks during the exposure process may become important issues as these masks are subject to rigorous image placement and flatness change. The reflective masks used for EUVL absorb energy during exposure, and the temperature of the mask rises as a result. This can cause thermomechanical deformation that can reduce the pattern quality. Therefore, it is necessary to predict and optimize the effect of energy transmitted from the extreme ultraviolet (EUV) light source and the resultant patterns of complex multilayer structured EUV masks. Our study shows that temperature accumulation and deformation of the EUV mask are dependent on the absorber structure. ? 2018 SPIE.