Apparatus and methods for detecting overlay errors using scatterometry
First Claim
Patent Images
1. A single metrology tool, comprising:
- a scatterometry overlay measurement system configured to measure overlay on a combined mark having a scatterometry overlay target disposed over a scatterometry CD or profile target; and
a CD-SEM system configured to measure critical dimension on the CD or profile target of the combined mark,wherein the scatterometry overlay measurement system is configured to measure overlay on both the scatterometry overlay target and the scatterometry CD or profile target based on a scatterometry overlay technique without using calibration or a model regression technique, wherein the scatterometry overlay technique is a phase based technique that includes representing each measured optical signal as a set of periodic functions having a plurality of known parameters and an unknown overlay error parameter and analyzing the set of periodic functions to solve for the unknown overlay error parameter to thereby determine the overlay error.
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Abstract
Disclosed is a combined scatterometry mark comprising a scatterometry critical dimension (CD) or profile target capable of being measured to determine CD or profile information and a scatterometry overlay target disposed over the scatterometry CD or profile target, the scatterometry overlay target cooperating with the scatterometry CD or profile target to form a scatterometry mark capable of being measured to determine overlay.
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Citations
7 Claims
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1. A single metrology tool, comprising:
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a scatterometry overlay measurement system configured to measure overlay on a combined mark having a scatterometry overlay target disposed over a scatterometry CD or profile target; and a CD-SEM system configured to measure critical dimension on the CD or profile target of the combined mark, wherein the scatterometry overlay measurement system is configured to measure overlay on both the scatterometry overlay target and the scatterometry CD or profile target based on a scatterometry overlay technique without using calibration or a model regression technique, wherein the scatterometry overlay technique is a phase based technique that includes representing each measured optical signal as a set of periodic functions having a plurality of known parameters and an unknown overlay error parameter and analyzing the set of periodic functions to solve for the unknown overlay error parameter to thereby determine the overlay error. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification