Paper
27 December 2002 High-Resolution Photomask Phase Measurement Tool
Author Affiliations +
Abstract
We describe the application of a novel imaging technique to ultra-high spatial resolution measurements of photomask phase shift. An Actinix TMT-193 photomask transmission tool has been retrofitted with a breadboard Mach-Zehnder interferometer and ancillary signal detection electronics and software to demonstrate actinic phase shift measurement capability for ArF-generation photomasks. Using a simple proof-of-principle layout, we have successfully acquired high-contrast interference fringe data on ultra-high resolution (250 nm) photomask geometries. Minimum detectable feature sizes are limited only by the resolution of the imaging system. The measurement techniques are suited to both embedded-attenuator and alternating-aperture phase-shift masks, and may be directly applied to F2-generation mask tools. Engineering advances in the laser source will increase measurement precision to the 0.4° level as called for in the 2001 ITRS. We discuss the tool architecture and measurement method, and present recent results of phase scans performed on a customer-supplied MoSi EAPSM.
© (2002) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Andrew J. Merriam and James J. Jacob "High-Resolution Photomask Phase Measurement Tool", Proc. SPIE 4889, 22nd Annual BACUS Symposium on Photomask Technology, (27 December 2002); https://doi.org/10.1117/12.467846
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CITATIONS
Cited by 2 scholarly publications.
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KEYWORDS
Photomasks

Phase shifts

Interferometers

Phase measurement

Fringe analysis

Spatial resolution

Metrology

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