Laser-driven particle removal from CNT pellicles

Extreme Ultraviolet (EUV) lithography is key enabler for advanced semiconductor manufacturing, enabling highresolution patterning and increased device density. However, as device scaling progresses, particle contamination on EUV masks has become a serious bottleneck, requiring more stringent control measures. Carbon nanotube (CNT) pellicles, with their high EUV transmittance and excellent thermal and mechanical properties, are viable options for protecting mask surfaces. Nevertheless, particle adhesion during handling and operation can limit their operational lifetime. In this study, we present a non-contact laser-based technique that selectively removes adhered particles from CNT pellicles by inducing localized thermal contraction, without damaging the membrane. Surface analysis verified that the pellicle structure remained intact after cleaning. This approach enables safe reuse of high-performance CNT pellicles, offering a feasible pathway for reducing operational costs and enhancing mask contamination control in next-generation EUV lithography.