
Proceedings Paper
A novel photo-thermal setup for determination of absorptance losses and wavefront deformations in DUV opticsFormat | Member Price | Non-Member Price |
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Paper Abstract
Lens heating due to absorbed UV laser radiation can diminish the achievable spatial resolution of
the lithographic process in semiconductor wafer steppers. At the Laser- Laboratorium Göttingen a
measurement system for quantitative registration of this thermal lens effect was developed. It is
based upon a strongly improved Hartmann-Shack wavefront sensor with extreme sensitivity,
accomplishing precise online monitoring of wavefront deformations of a collimated test laser beam
transmitted through the laser-irradiated site of a sample. Caused by the temperature-dependent
refractive index as well as thermal expansion, the formerly plane wavefront of the test laser is
distorted to form a rotationally symmetric valley, being equivalent to a convex lens. The observed
wavefront distortion is a quantitative measure of the absorption losses in the sample. Thermal
theory affords absolute calibration of absorption coefficients.
Paper Details
Date Published: 7 March 2008
PDF: 10 pages
Proc. SPIE 6924, Optical Microlithography XXI, 69242P (7 March 2008); doi: 10.1117/12.775453
Published in SPIE Proceedings Vol. 6924:
Optical Microlithography XXI
Harry J. Levinson; Mircea V. Dusa, Editor(s)
PDF: 10 pages
Proc. SPIE 6924, Optical Microlithography XXI, 69242P (7 March 2008); doi: 10.1117/12.775453
Show Author Affiliations
K. Mann, Laser-Lab. Göttingen e.V. (Germany)
A. Bayer, Laser-Lab. Göttingen e.V. (Germany)
U. Leinhos, Laser-Lab. Göttingen e.V. (Germany)
A. Bayer, Laser-Lab. Göttingen e.V. (Germany)
U. Leinhos, Laser-Lab. Göttingen e.V. (Germany)
Published in SPIE Proceedings Vol. 6924:
Optical Microlithography XXI
Harry J. Levinson; Mircea V. Dusa, Editor(s)
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