VIEWPORT ASSEMBLY FOR AN EXTREME ULTRAVIOLET LIGHT SOURCE

原文（中国語）

An assembly includes a window useful for optical access to an interior of an extreme ultraviolet (EUV) light source vessel, the window having a transmission band and a protector configured to shield the window from the interior of the EUV light source vessel, the protector comprising a sheet with a surface facing the window across a gap, the sheet having a thermal conductivity in the range of 10 to 2000 W/(m·K). The sheet can be a sapphire sheet, and can have an optical coating on the surface facing the window, the coating reflecting at least some radiation outside the transmission band, and the opposite side of the sheet can be bare sapphire.