Thermal distortion model of mask for extreme ultraviolet lithography during periodic scanning exposure

In order to estimate the accuracy of patterns fabricated by EUV lithography (EUVL), it is necessary to clarify the thermal distortion of an EUVL mask caused by the energy absorbed during exposure. A dynamic thermal distortion model that combines 3-dimensional heat transfer and in-plane stress models has been developed, and was used to investigate the basic worst-case thermal-distortion characteristics of an EUVL mask during periodic scanning exposure and their effect on mask accuracy.