Accelerated Hydrogen-Plasma Screening of Nanoscale Protective Layers for EUV Pellicle Reliability

Extreme ultraviolet (EUV) lithography, operating at a wavelength of 13.5 nm, relies on pellicle membranes to protect photomasks during semiconductor manufacturing. However, hydrogen plasma generated during EUV exposure can progressively degrade pellicle materials, reducing optical transmission and device reliability. Direct evaluation of pellicle durability in EUV scanners is costly and time-intensive because degradation typically occurs only after thousands of wafer exposures. Here, we introduce an accelerated hydrogen plasma treatment (AHPT) platform to rapidly evaluate the stability of nanoscale protective layers for EUV pellicle systems. Thin-film stacks consisting of a metal-silicide core layer capped with ∼10 nm SiN x, SiC, or SiO 2 were exposed to controlled hydrogen plasma using an ICP-RIE system. Nanoscale structural and chemical changes were characterized by Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS) depth profiling, Secondary Ion Mass Spectrometry (SIMS), and Atomic Force Microscopy (AFM). The results show that SiN x undergoes significant oxidation and hydrogen retention, while SiC exhibits thermal instability and carbon diffusion. In contrast, SiO 2 demonstrates the highest resistance to hydrogen penetration and interfacial degradation. These results establish AHPT as a rapid screening method for nanoscale pellicle materials and interfaces, enabling efficient identification of hydrogen-resistant protective layers for EUV lithography applications.