Asml Netherlands B.v.

Carl Zeiss Smt Gmbh

Mark Zellenrath

Gerardus Carolus Johannus Hofmans

Sven Gunnar Krister Magnusson

Hubertus Antonius Geraets

Dirk Heinrich Ehm

Stefan-Wolfgang Schmidt

Edwin Te Sligte

Edgar Osorio

Hella Logtenberg

An EUV lithography system () includes: at least one optical element () having an optical surface () arranged in a vacuum environment () of the EUV lithography system (), and a feed device () for feeding hydrogen into the vacuum environment (), in which at least one silicon-containing surface () is arranged. The feed device () additionally feeds an oxygen-containing gas into the vacuum environment () and has a metering device () that sets an oxygen partial pressure (p) at the at least one silicon-containing surface () and/or at the optical surface ().

EUV lithography system and operating method

A method of measuring focus of a lithographic projection apparatus includes exposure of a photoresist covered test substrate with a plurality of verification fields. Each of the verification fields includes a plurality of verification markers, and the verification fields are exposed using a predetermined focus offset. After developing, an alignment offset for each of the verification markers is measured and translated into defocus data using a transposed focal curve.

Method of measuring focus of a lithographic projection apparatus

A method of measuring focus of a lithographic projection apparatus includes exposure of a photoresist covered test substrate with a plurality of verification fields. Each of the verification fields includes a plurality of verification markers, and the verification fields are exposed using a predetermined focus offset FO. After developing, an alignment offset for each of the verification markers is measured and translated into defocus data using a transposed focal curve. The method according to an embodiment of the invention may result in a focus-versus alignment shift sensitivity up to 50 times higher (typically dX,Y/dZ=20) than conventional approaches.

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Veldhoven, Netherlands

Mark Zellenrath