Upgrade to the SHARP EUV mask microscope

Abstract

The Sharp High-NA Actinic Reticle review Project (SHARP) is a synchrotron-based, extreme ultraviolet (EUV) microscope dedicated to photomask research. A potential upgrade to the SHARP microscope is presented. The upgrade includes changing the light path in the instrument from its current off-axis configuration to an on-axis configuration. This change allows for an increased working distance of 2.5 mm or more. A central obscuration, added to the zoneplate aperture, blocks stray light from reaching the central part of the image, thus improving the image contrast. The imaging performance of the two configurations is evaluated by means of ray tracing.

Analysis of extreme ultraviolet mask defect inspection based on complex amplitudes of the aerial images

“…After repairing or compensating for the mask defects, the aerial image inspection of the mask should be carried out to ensure that the defects have been successfully repaired or compensated. Currently, the existing aerial image detection equipment mainly includes the Aerial Image Measurement System (AIMS) [9] [10] developed by Carl Zeiss and the High Numerical Aperture Actinic Reticle Review Project (SHARP) developed by SEMATECH [11]. Different from EUV lithography, AIMS uses a projection objective system with a magnification greater than 500 to collect enlarged aerial images by a CCD camera [11].…”

“…Currently, the existing aerial image detection equipment mainly includes the Aerial Image Measurement System (AIMS) [9] [10] developed by Carl Zeiss and the High Numerical Aperture Actinic Reticle Review Project (SHARP) developed by SEMATECH [11]. Different from EUV lithography, AIMS uses a projection objective system with a magnification greater than 500 to collect enlarged aerial images by a CCD camera [11]. As shown in Fig.…”