Unveiling the individual impact of hydrogen radicals and vacuum EUV photons on pellicle-like materials under varying thermal conditions

Pellicles are crucial for protecting reticles from the particle contamination in ASML systems. This study investigates the distinct impacts of hydrogen radicals and vacuum EUV photons on pellicle-like materials. We focus on the effects of these elements on 50 nm thick semi-amorphous SiN thin films at various surface temperatures. Characterization techniques such as real-time ellipsometry, in-situ XPS, ToF-SIMS, NRA, SEM and optical microscopy were used for comprehensive analysis. Surprisingly, while hydrogen radicals singularly did not evoke discernible alterations in the SiN thin films, vacuum EUV photons induced significant chemical and morphological changes, even at lower temperatures. These changes included hydrogen release and the formation of blister-like defects. On the other hand, higher temperature exposure did not cause blister-like defects despite increased hydrogen release. The results enhance our understanding of the intricate interactions within pellicle-like materials, offering crucial insights for advancing EUV lithography technology.