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Proceedings Paper

Application of blazed gratings for determination of equivalent primary azimuthal aberrations
Author(s): Joseph P. Kirk; Christopher J. Progler
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Paper Abstract

Aberrations are determined from wafers exposed using a test reticle having blazed gratings with orientations from 0 to 337.5 degrees in increments of 22.5 degrees. The image of the phase grating is micro stepped thorough focus on the surface of high absorption photoresist. A second blanket exposure is applied to the latent images to make the developed resist images have a surface relief linearly related to the aerial image intensity. The first order diffraction efficiency of this surface grating is directly propagational to the first harmonic of the surface relief. This diffraction efficiency is recorded as a digitized dark- field image and processed to evalute the aberrations. These images are simulated and matched to those recorded in the photoresist by adjusting the aberrations to achieve a best match. The primary azimuthal aberration contributions are separated by Fourier analysis into coma, astigmatism, 3 leaf clover, etc. and laser used to indicate lens quality. Several grating frequencies are required to separate higher order components of each azimuthal aberration. Only one grating frequency is used in the data reported here and all orders of each azimuthal aberration are lumped into equivalent primary azimuthal aberrations.

Paper Details

Date Published: 26 July 1999
PDF: 7 pages
Proc. SPIE 3679, Optical Microlithography XII, (26 July 1999); doi: 10.1117/12.354375
Show Author Affiliations
Joseph P. Kirk, IBM Microelectronics Div. (United States)
Christopher J. Progler, IBM Microelectronics Div. (United States)


Published in SPIE Proceedings Vol. 3679:
Optical Microlithography XII
Luc Van den Hove, Editor(s)

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