Reflective optical element for EUV lithography, hydrogen plasma sensor and EUV lithography system with it

摘要

The invention relates to a reflective optical element (1) for EUV lithography, comprising: a substrate (2), a reflective coating (3) applied to the substrate (2), and a cover layer applied to the reflective coating (3) ( 4). The cover layer (4) and / or at least one layer of the reflective coating (3) is / are designed as a hydrogen plasma sensor. The invention also relates to a hydrogen plasma sensor and to an EUV lithography system having at least one such reflective optical element (1) and / or having at least one hydrogen plasma sensor.