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Proceedings Paper

In situ monitoring during ion-beam etching of multilayer dielectric gratings: simulation and experiment
Author(s): Hua Lin; Lifeng Li; Lijiang Zeng
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Paper Abstract

Utilizing the in-situ monitoring scheme, we obtained the relationship between diffraction efficiency and etching time under different ion beam conditions. Since the distribution of photoresist is found to be changing innegligible during etching and causes difficulties in determining the end-point, it becomes necessary to consider the photoresist effect on the diffraction efficiency. Taking into account the influence of the etch ratio of photoresist to hafnia, we simulated the efficiencies of the reflected -1st-order diffraction (-1st-order Littrow mount, λ=1064nm, TE polarization) as functions of etched depth. Though the midway evolution of the grating profile is complicated, the main features of the simulated curves agree very well with those of the experimental monitoring curves. With this knowledge, by in-situ monitoring the diffraction intensity, we can obtain good estimates of the etched depth and the erosion progress of the photoresist mask, which are of great help to determine the etching end-point and suitable working parameters of the etcher, and so as to achieve much better cost-efficiency. Employing the proposed in-situ monitoring scheme, multilayer dielectric gratings with retroreflected efficiency approaching 100% were fabricated.

Paper Details

Date Published: 7 February 2005
PDF: 7 pages
Proc. SPIE 5636, Holography, Diffractive Optics, and Applications II, (7 February 2005); doi: 10.1117/12.573611
Show Author Affiliations
Hua Lin, Tsinghua Univ. (China)
Lifeng Li, Tsinghua Univ. (China)
Lijiang Zeng, Tsinghua Univ. (China)

Published in SPIE Proceedings Vol. 5636:
Holography, Diffractive Optics, and Applications II
Yunlong Sheng; Dahsiung Hsu; Chongxiu Yu; Byoungho Lee, Editor(s)

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