EUV Window Decontamination via Hydrogen Heating

The patent applies preliminary action by introducing hydrogen gas and applying heat to the window surface before contamination significantly degrades performance. The optical sensing module detects tin contamination early, and the decontamination process (hydrogen gas introduction + heating) is initiated proactively while the EUV source continues operating, rather than waiting for complete contamination or interrupting operation for cleanup

The patent implements continuity of useful action by designing a decontamination system that operates concurrently with EUV radiation generation. The optical sensing module continuously monitors window contamination, and when thresholds are exceeded, the hydrogen gas supply and heating elements activate to remove contamination in-situ, allowing the EUV source to maintain continuous operation without interruption for maintenance

The patent applies feedback through the optical sensing module that continuously monitors the window surface for tin contamination. The sensed contamination level is fed back to the control system, which automatically activates the decontamination process (hydrogen gas supply and heating) when contamination thresholds are exceeded, creating a closed-loop system that maintains window cleanliness and system integrity

The system implements self-service by automatically detecting and removing its own contamination without external intervention. The optical sensing module monitors the window, and when contamination is detected, the control system automatically activates the hydrogen gas supply and heating elements to clean the window in-situ, allowing the EUV source to self-maintain during operation