Kla Tencor Corporation

Yoni Shalibo

Amnon Manassen

Vladimir Levinski

Yuri Paskover

Gilad Laredo

Ariel Hildesheim

Shlomo Eisenbach

Metrology tools and methods are provided, which estimate the effect of topographic phases corresponding to different diffraction orders, which result from light scattering on periodic targets, and adjust the measurement conditions to improve measurement accuracy. In imaging, overlay error magnification may be reduced by choosing appropriate measurement conditions based on analysis of contrast function behavior, changing illumination conditions (reducing spectrum width and illumination NA), using polarizing targets and/or optical systems, using multiple defocusing positions etc. On-the-fly calibration of measurement results may be carried out in imaging or scatterometry using additional measurements or additional target cells.

Topographic phase control for overlay measurement

Metrology methods and tools are provided, which enhance the accuracy of the measurements and enable simplification of the measurement process as well as improving the correspondence between the metrology targets and the semiconductor devices. Methods comprise illuminating the target in a Littrow configuration to yield a first measurement signal comprising a &#x2212;1diffraction order and a 0diffraction order and a second measurement signal comprising a +1distraction order and a 0diffraction order, wherein the &#x2212;1diffraction order of the first measurement signal and the +1diffraction order of the second measurement signal are diffracted at 180&#xb0; to a direction of the illumination, performing a first measurement of the first measurement signal and a second measurement of the second measurement signal, and deriving metrology metric(s) therefrom. Optionally, a reflected 0diffraction order may be split to yield components which interact with the &#x2212;1and +1diffraction orders.

Off-axis illumination overlay measurement using two-diffracted orders imaging

Growing community of inventors

Binyamina, Israel

Yoni Shalibo