Interferometer for overlay measurements
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United States of America Patent
Stats
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Aug 21, 2012
Grant Date -
Oct 22, 2009
app pub date -
Apr 21, 2009
filing date -
Apr 22, 2008
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
In general, in a first aspect, the invention features a system including an interferometer configured to direct test light to an overlay target and subsequently combine it with reference light to form an interference pattern, the test and reference light being derived from a common source, a multi-element detector, one or more optics to image the overlay target on the multi-element detector; and an electronic processor in communication with the multi-element detector. The overlay target includes a first pattern and a second pattern and the electronic processor is configured to determine information about the relative alignment between the first and second patterns.
First Claim
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International Classification(s)
Cited Art Landscape
Patent Citation Ranking
- 12 Citation Count
- G01B Class
- 58.10 % this patent is cited more than
- 13 Age
