
Proceedings Paper
Zero-order imaging of device-sized overlay targets using scatterfield microscopyFormat | Member Price | Non-Member Price |
---|---|---|
$17.00 | $21.00 |
Paper Abstract
Patterns of lines and trenches with nominal linewidths of 50 nm have been proposed for use as an overlay target
appropriate for placement inside the patterned wafer die. The National Institute of Standards and Technology (NIST)
Scatterfield Targets feature groupings of eight lines and/or trenches which are not resolvable using visible-wavelength
bright-field microscopy. Such repetitive patterns yield zero-order images superimposed by interference effects from
these finite gratings. Zero-order imaging is defined as the collection of specular reflection from periodic structures
without the collection of any possible diffracted beams. As our lines and trenches are formed in different
photolithographic steps, the overlay offset can be derived from the relative displacement of these zero-order responses.
Modeling this phenomenon will require a thorough characterization of the transmission of light through all points in the
optical path as a function of position, angle, and polarization. Linear polarization parallel and perpendicular to these
lines and trenches is investigated as a possible enhancer of overlay offset measurement repeatability. In our particular
case, nominally unpolarized light proved most repeatable.
Paper Details
Date Published: 5 April 2007
PDF: 10 pages
Proc. SPIE 6518, Metrology, Inspection, and Process Control for Microlithography XXI, 65180F (5 April 2007); doi: 10.1117/12.716457
Published in SPIE Proceedings Vol. 6518:
Metrology, Inspection, and Process Control for Microlithography XXI
Chas N. Archie, Editor(s)
PDF: 10 pages
Proc. SPIE 6518, Metrology, Inspection, and Process Control for Microlithography XXI, 65180F (5 April 2007); doi: 10.1117/12.716457
Show Author Affiliations
Bryan M. Barnes, National Institute of Standards and Technology (United States)
Lowell P. Howard, National Institute of Standards and Technology (United States)
Precera, Inc. (United States)
Jay Jun, National Institute of Standards and Technology (United States)
Lowell P. Howard, National Institute of Standards and Technology (United States)
Precera, Inc. (United States)
Jay Jun, National Institute of Standards and Technology (United States)
Pete Lipscomb, ISMI SEMATECH (United States)
Richard M. Silver, National Institute of Standards and Technology (United States)
Richard M. Silver, National Institute of Standards and Technology (United States)
Published in SPIE Proceedings Vol. 6518:
Metrology, Inspection, and Process Control for Microlithography XXI
Chas N. Archie, Editor(s)
© SPIE. Terms of Use
