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Proceedings Paper

EUV wavefront metrology at EUVA
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Paper Abstract

Precise measurements of the wavefront aberrations of projection optics with 0.1 nm RMS accuracy are indispensable to develop the extreme ultraviolet (EUV) lithography. In order to study measurement methods, we built the Experimental EUV Interferometer (EEI) that has built-in Schwarzschild-type optics as test optics and was supplied with EUV radiation of 13.5 nm in wavelength from a synchrotron radiation facility as a source light. The EEI can evaluate several methods of EUV interferometory replacing optical parts easily. Those methods are dividable into two categories, namely point diffraction interferometer (PDI) and lateral shearing interferometer (LSI) and those were experimentally compared. Finally, 0.045nm RMS of reproducibility was achieved with PDI method and the residual systematic error after removing specified errors was reduced to 0.064nm RMS excluding axial symmetrical aberrations. In addition, one of LSI-type methods also proved to have almost enough accuracy for the assembly of the projection optics.

Paper Details

Date Published: 24 March 2006
PDF: 8 pages
Proc. SPIE 6152, Metrology, Inspection, and Process Control for Microlithography XX, 61522O (24 March 2006); doi: 10.1117/12.656039
Show Author Affiliations
Chidane Ouchi, Extreme Ultraviolet Lithography System Development Association (Japan)
Seima Kato, Extreme Ultraviolet Lithography System Development Association (Japan)
Masanobu Hasegawa, Extreme Ultraviolet Lithography System Development Association (Japan)
Takayuki Hasegawa, Extreme Ultraviolet Lithography System Development Association (Japan)
Hideo Yokota, Extreme Ultraviolet Lithography System Development Association (Japan)
Katsumi Sugisaki, Extreme Ultraviolet Lithography System Development Association (Japan)
Masashi Okada, Extreme Ultraviolet Lithography System Development Association (Japan)
Katsuhiko Murakami, Extreme Ultraviolet Lithography System Development Association (Japan)
Jun Saito, Extreme Ultraviolet Lithography System Development Association (Japan)
Masahito Niibe, Univ. of Hyogo (Japan)
Mitsuo Takeda, Univ. of Electro-Communications (Japan)


Published in SPIE Proceedings Vol. 6152:
Metrology, Inspection, and Process Control for Microlithography XX
Chas N. Archie, Editor(s)

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