Carl Zeiss Introduces New Metrology System at SPIE Photomask Conference

Carl Zeiss introduces its PROVE™ Registration and Overlay Metrology System for photomasks at SPIE Photomask Conference in Monterey, California.

PROVE™ measures image placement on photomasks with superior resolution, meeting the challenging requirements of the 32nm technology node and beyond.

Further extension of 193nm lithography to the next technology nodes by introducing strong optical proximity corrections and double patterning requires new approaches for photomask registration and overlay metrology.

With its diffraction-limited, high-resolution imaging optic working at the lithographic relevant 193nm wavelength the new PROVE™ system opens up entirely new perspectives in registration metrology. PROVE™ allows for measurement of the smallest production features without placing registration marks. “This real in-die registration metrology is a huge benefit for our customers in Mask Manufacturing. For the first time in history, mask makers are able to measure and analyse registration where it really matters. Additionally, with increasing resolution demands e.g. for EUV lithography, we can extend our tool capabilities to the upcoming technology nodes,” explains Dr. Oliver Kienzle, managing director of Semiconductor Metrology Systems Division of Carl Zeiss SMT.

The proprietary autofocus and calibration strategy of the new system enables a repeatability of below 0.5nm and an accuracy of below 1nm for best registration measurement performance.

Even in manufacturing of mask writers the PROVE™ system is used to tune the pattern generators to improve pattern placement results and to minimize registration errors on photomasks. Recently Carl Zeiss reported about the shipment of the first tool to NuFlare Technology Inc., the worlds leading supplier of e-beam based mask writers.

The next system to a Mask Shop customer will be delivered at the end of this month.

Features & benefits at a glance:

• PROVE™ measures registration and overlay on photomasks with sub-nanometer repeatability and accuracy
• PROVE™ offers the best resolution with 193nm optics for the measurement of small, freely selectable production features.
• PROVE™ enables single exposure application by
  • measuring local registration errors in areas where registration markers cannot be placed
  • increasing useable mask areas by eliminating required marker space
• PROVE™ enables Double Pattering/ Spacing application by
  • measuring individual mask(s) relative to design
  • superimposing results to extract resulting local overlay error
• PROVE™ works with a NA of 0.6 for greater depth of focus and large working distance
• PROVE™ introduces a patented autofocus and calibration strategy for highest accuracy.
• PROVE™ provides superior stage stability for excellent repeatability performance.
• PROVE™ enables the measurement of most advanced types of photomask such as OMOG and EUV and is compatible with all types of pellicle.

Source: http://www.smt.zeiss.com/