Comparison of Al- and Hf-based hybrid photoresists grown by molecular layer deposition for extreme ultraviolet lithography.

This article focuses on the development and characterization of aluminum-based hybrid "alucone" thin films synthesized via molecular layer deposition (MLD) for use as negative-tone resists in extreme ultraviolet (EUV) lithography. Two types of alucone films—standard and oxygen-rich—were compared in terms of composition, sensitivity, and resolution, with electron-beam lithography serving as a proxy for EUV exposure. Oxygen-rich alucone exhibited higher sensitivity (4800 μC/cm²) than standard alucone (>18,000 μC/cm²), while both achieved a resolution of approximately 20 nm, surpassing the 50 nm resolution of previously studied hafnium-based "hafnicone" films. Differences in resist performance between alucone and hafnicone were attributed to the oxophilicity of the metal atoms, with hafnium’s higher oxophilicity leading to greater sensitivity but lower resolution due to nanoparticle formation dynamics. These findings enhance understanding of how MLD film chemistry influences irradiation response, informing the optimization of resist materials for advanced microelectronics fabrication.