In the process of lithography using ultra violet light sources for semiconductor devices, most of defects are made by sub-micrometer pollutants generated at photochemical reactions. We proposed and developed a novel vibration-insensitive on-axis interferometer with a sub-micrometer lateral resolution by using the interference between two beams: one scattered from defects and the other reflected from a reference area without defects. The proposed system was successfully demonstrated to detect a small Al defect of 0.5 μm diameter within the inspection time of less than 30 minutes over the area of the photo-mask which is 6 inch by 6 inch square.
© 2013 Optical Society of Korea
(120.4630) Instrumentation, measurement, and metrology : Optical inspection
(120.4640) Instrumentation, measurement, and metrology : Optical instruments
(120.4820) Instrumentation, measurement, and metrology : Optical systems
(220.4830) Optical design and fabrication : Systems design
Original Manuscript: December 5, 2012
Revised Manuscript: January 22, 2013
Manuscript Accepted: January 22, 2013
Published: February 25, 2013
Sangon Lee, Jae Heung Jo, Jong Soo Kim, and Il Kweon Moon, "Detection System for Sub-micrometer Defects of a Photo-mask Using On-axis Interference between Reflected and Scattered Lights," J. Opt. Soc. Korea 17, 73-80 (2013)
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