The impact of the residual stress on the EUV pellicle

Abstract

High resolution patterning on the chip could be achieved by extreme ultraviolet lithography (EUVL). However, the defect on the mask becomes more important issue with very short wavelength (13.5 nm). Using the pellicle which could protect the mask from the defects can support high volume manufacturing (HVM). Most of the materials considered for pellicle have relatively high extinction coefficient in EUV region. Therefore, the thickness of the pellicle should be ~ nm thin. The stress of the pellicle is dependent not only on the temperature but also on the mechanical properties of the pellicle. The stress induced by the gravity was small compared to the thermal stress. However, the residual stress should be also considered since it is dependent on the pellicle manufacturing environment and this stress is comparable with the thermal stress. Our result shows the importance of the lowering the pellicle fabrication temperature in terms of the extending the lifetime during the scanning process.