Temperature behavior of pellicles in extreme ultraviolet lithography

Abstract

We present a theoretical analysis of the temperature behavior of pellicles in extreme ultraviolet (EUV) lithography. Using modified heat transfer equations and accounting for the cooling mechanism during exposure, we calculate the temperature of the pellicle due to EUV beam absorption as a function of the incident EUV power. We find the temperature rise to be less than 620 K for a 10 ms incident EUV beam with a power of 100 W. The recovery time after EUV beam exposure is also calculated to be less than 53 ms, which is significantly smaller than the time interval between the typical EUV beam exposures (similar to 300 ms). Thus, we can neglect the thermal heating problem for practical EUV pellicles in mass EUV processes.