REFLECTIVE PHOTOMASK AND REFLECTION-TYPE MASK BLANK

A reflective photomask includes a substrate with a substrate layer of a low thermal expansion material. The substrate layer includes a main portion of a first structural configuration and an auxiliary portion of a second structural configuration of the low thermal expansion material. The auxiliary p...

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Bibliographic Details
Main Authors Schedel Thorsten, Bender Markus
Format Patent
LanguageEnglish
Published 20.04.2017
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Summary:A reflective photomask includes a substrate with a substrate layer of a low thermal expansion material. The substrate layer includes a main portion of a first structural configuration and an auxiliary portion of a second structural configuration of the low thermal expansion material. The auxiliary portion is formed in a frame section surrounding a pattern section of the substrate. A multilayer mirror is formed on a first surface of the substrate. A reflectivity of the multilayer mirror is at least 50% at an exposure wavelength below 15 nm. A frame trench extending through the multilayer mirror exposes the substrate in the frame section. The auxiliary portion may include scatter centres for out-of-band radiation.
Bibliography:Application Number: US201615179775