Enhancement of photosensitivity and stability of Sn-12 EUV resist by integrating photoactive nitrate anion

Abstract

The semiconductor industry is currently transitioning to advanced extreme-ultraviolet lithography (EUVL) to address the challenges facing the use of photolithography in microprocessor and memory chip integration. This shift has sparked a surge in novel inorganic EUV photoresist research. However, several technical issues, such as insufficient EUV sensitivity, poor understanding of the photochemistry, and poor stability, have emerged. Here, the EUV sensitivity and stability of state-of-the-art tin oxo clusters are enhanced by integration with the photoactive nitrate anion to give [(BuSn)12O14(OH)6](NO3)2 (TinNO3). The findings of the study reveal that nitrate anions in TinNO3 showing the photosensitivity as low as 32 mJ/cm2 and maintaining stability irrespective of the post-exposure environment. Furthermore, TinNO3 possesses superior resistance to dry etching, enabling selective etching of Si and the amorphous carbon layer. Finally, through intensive optimization of the post-exposure bake parameters, photoresist-substrate adhesion, and development conditions, well-ordered CD 45 nm L/S patterns of TinNO3 thin-film were achieved using ArF lithography.