I. Kallioniemi et al., OPTICAL SCATTEROMETRY OF SUBWAVELENGTH DIFFRACTION GRATINGS - NEURAL-NETWORK APPROACH, Applied optics, 37(25), 1998, pp. 5830-5835
Optical scatterometry is a method for the on-line measurement of the g
eometry of a diffraction grating; which is deduced from diffraction-pa
ttern data. We demonstrate the use of a neural network as a promising
method for performing an accurate quantitative characterization of the
geometry. As an example, we show the deduction of the geometry of a g
rating with subwavelength grooves with a ms accuracy of 1.9 for the sl
ope of the groove walls, 0.7 nm for the linewidth, and 1.0 nm for the
groove depth. (C) 1998 Optical Society of America.