Paper
24 March 2008 Probe-pattern grating focus monitor through scatterometry calibration
Author Affiliations +
Abstract
This paper presents a new highly sensitive scatterometry based Probe-Pattern Grating (PPG) focus monitor and its printing assessment on an advanced exposure tool. The high sensitivity is achieved by placing transparent lines spaced at the strong focus spillover distance from the centerline of a 90 degree phase-shifted probe line that functions as an interferometer detector. The monitor translates the focus error into the probe line trench depth, which can be measured by scatterometry techniques. The sensitivity of the defocus measurement through scatterometry calibration is around 1.1nm defocus / nm trench depth. This result indicates that the PPG focus monitor from a single wafer focus setting can detect the defocus distance to well under 0.05 Rayleigh Units.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jing Xue, Costas J. Spanos, and Andrew R. Neureuther "Probe-pattern grating focus monitor through scatterometry calibration", Proc. SPIE 6922, Metrology, Inspection, and Process Control for Microlithography XXII, 692225 (24 March 2008); https://doi.org/10.1117/12.773191
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CITATIONS
Cited by 1 scholarly publication.
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KEYWORDS
Scatterometry

Calibration

Scatter measurement

Critical dimension metrology

Interferometers

Phase shifts

Spherical lenses

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