Carl-zeiss-smt Ag

Frank Stietz

Marco Wedowski

Roman Klein

Bas M Mertens

Frederik Bijkerk

Andrey E Yakshin

Eric Louis

The invention relates to a method for preventing contamination on the surfaces of optical elements comprising a multi-layer system, during the exposure thereof to radiation at signal wave lengths in an evacuated closed system comprising a residual gas atmosphere, whereby the photocurrent generated by means of photo emission from the radiated surface of the multi-layer system is measured. The photocurrent is used to regulate the gas composition of the residual gas. The gas composition is altered according to at least one lower and one upper threshold value of the photocurrent. The invention also relates to a device for regulating the contamination on the surface of at least one optical element during exposure and an EUV-lithographic device and a method for cleaning the surfaces of the optical elements contaminated by carbon.

Device, EUV lithographic device and method for preventing and cleaning contamination on optical elements

In order to reduce contamination of optical elements which comprise a multilayer system on a substrate, it is proposed that the layer material and/or the layer thickness of at least one layer of the multilayer system are/is selected such that the standing wave which forms during reflection of the irradiated operating wavelength, forms a node of the electrical field intensity (node condition) in the area of the free interface of the multilayer system. Furthermore, a method for determining a design of a multilayer system, as well as a manufacturing process and a lithography apparatus are described.

Optical element and method for its manufacture as well as lithography apparatus and method for manufacturing a semiconductor device

Device, EUV-lithographic device and method for preventing and cleaning contamination on optical elements

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Lauchheim, Germany

Frank Stietz