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US 8,139,232 B2Granted
Multiple measurement techniques including focused beam scatterometry for characterization of samples
AssigneeRudolph Technologies, Inc.
InventorsRobert Gregory Wolf, Michael J. Kotelyanskii
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Abstract
A system for monitoring thin-film fabrication processes is herein disclosed. Diffraction of incident light is measured and the results are compared to a predictive model based on at least one idealized or nominal structure. The model and/or the measurement of diffracted incident light may be modified using the output of one or more additional metrology systems.
Claims21
An ellipsometric metrology tool for optically measuring characteristics of a substrate comprising:
- at least one light source adapted to output a beam of incident light;
- a first optical element for focusing the incident light onto a metrology site of the substrate having a periodic structure formed thereon at a plurality of incident angles and at a plurality of azimuthal angles, an optical axis of the first optical element being inclined at an oblique angle with respect to a plane of the substrate;
- a second optical element for directing reflected light reflected from the metrology site to a detector, the detector output being at least partially correlated to a polarization state of the incident light, a phase shift of the reflected light, at least one of the plurality of incident angles, and at least one of the plurality of azimuthal angles of the incident light with respect to the metrology site.
A method of monitoring a fabrication process comprising:
- directing a beam of light at a metrology site of a sample having a periodic structure formed thereon at a range of oblique angles of incidence and a range of azimuthal angles, the respective ranges of the angles of incidence and azimuthal angles being disposed about an oblique optical axis, wherein the beam of light is of a known polarization state;
- collecting the beam of light upon reflection from the metrology site of the sample and directing it to a detector;
- and,
- outputting from the detector at least one array of data values that are at least partially correlated to the polarization state of the beam of light, a phase shift in the beam of light upon reflection, at least one of the angles of incidence of the beam of light and at least one of the azimuthal angles of the beam of light.
1 more element
Dependencies are inferred from the claim text.