Inverse propagation algorithm for angstrom accuracy interferometer

Inverse propagation algorithm for angstrom accuracy interferometer

Krieg, M.L.
Braat, J.J.M.

Applied Sciences

Imaging Science and Technology

2004-08-02

This paper will illustrate several approaches to retrieving the shape of aspherical reflective surfaces as used in EUV Lithography, from measurements from a previously reported angstrom-accuracy interferometer. First, the working principles of the interferometer will be reviewed, and typical measurement data expected from the instrument will be presented. Several methods will then be introduced for retrieving the reflector shape from such measurements. These methods will include approaches based on ray tracing, approximate diffraction calculations, and linearization of rigorous diffraction calculations which use a novel numerical scheme to reduce calculation time of the diffraction integral. The methods will be compared on the basis of accuracy, calculation time and extendibility.

inverse propagation
diffraction integral
ray tracing
interferometry

http://resolver.tudelft.nl/uuid:6aacb0cc-3851-48cb-b924-20d7496d245d

SPIE

0277-786X

Proceedings of SPIE, 2004 vol. 5531

Institutional Repository

conference paper

(c)2004 Krieg, M.L., Braat, J.J.M.