Abstract

A partially coherent system is introduced for defect inspection of periodic objects such as integrated circuit photomasks. An experimental investigation demonstrates that the new system is more robust in the presence of optical setup noise than the corresponding coherent spatial filtering system. The system illumination is provided by an array of mutually incoherent point sources that image onto a grid of opaque spots at the pupil plane. Nonperiodic defects are displayed at the image plane as bright structures against a dark background.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.