▎ 摘　　要

NOVELTY - The mirror (1a) has a substrate (S), and a layer arrangement formed such that light of wavelength of smaller than 250 nm incident on the mirror at an incident angle between 0 and 30 degrees is reflected with preset intensity. The arrangement has layer subsystems comprising a periodical sequence of two periodical portions (P3). The portions comprise two individual layers e.g. upper breaking layer (H ''') and lower breaking layer (L'''), made of different materials. The arrangement has layers e.g. barrier layer (B) and protection layer, made of graphene. USE - Mirror for use in a projection lens of a projection exposure plant for imaging a mask i.e. reticule, in an image plane using extreme UV radiations during a microlithography process (all claimed). ADVANTAGE - The mirror is designed such that it exhibits stable optical properties over entire service life even during high dosage of the extreme UV radiations and minimizes losses of scattered light of the projection lens. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a mirror. Barrier layer (B) Upper breaking layer (H''') Lower breaking layer (L''') Periodical portions (P3) Substrate (S) Mirror (1a)