Anisotropy; Contact hole; Effective medium theory; Ellipsometry
Issue Date
2006-02
Publisher
SPIE
Citation
Proceedings of SPIE - The International Society for Optical Engineering; SPIE 31st International Symposium on Advanced Lithography, v. 6155, Article no. 61550L
Abstract
We applied spectroscopic ellipsometry for possible determination of the size of contact holes. We fabricated contact hole
patterns in two dimensional array to increase sensitivity and the size of contact hole varied from 80 to 150 nm. Variation of
hole-diameter in few nm was distinguishable by comparing the features in ellipsometry parameter Δ, Ψ or the degree of
polarization spectra. These features could be used to estimate the size of contact holes once they were calibrated by other
techniques. When the photoresist film with dense contact hole pattern was regarded as a uniaxial material, the ellipsometry
spectra could be analyzed with anisotropic optical model. In the process, the average size of contact hole could be estimated
from the anisotropy of the film.