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Proceedings Paper

Single pass die-to-database tritone reticle inspection capability
Author(s): Bryan Reese; Jan Heumann; Norbert Schmidt
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Paper Abstract

Tritone reticle designs present many challenges for both photomask manufacturers and defect inspection equipment suppliers. From a fabrication standpoint, multi-write and process steps for tritone layers add levels of complexity and increased cost not encountered with most traditional binary (two tone) masks. For inspection tools, the presence of three distinctive light levels presents a challenge for algorithms originally designed to inspect gray scale data between two tones (black and white): especially for database transmitted light modes. While most die-to-die and STARlightTM inspections on tritone reticles produce successful results using binary algorithms, database inspections typically require two separate recipes to reveal all lithographically significant defects. With this dual-inspection technique, DNIR (Do Not Inspect Regions) are often added to eliminate the presence of third tone (typically Chrome) features: a process that adds considerable time to recipe creation. Additional workarounds when using binary inspection algorithms include implementing special light calibration techniques during setup in an effort to minimize nuisance defects caused by the presence of a third tone. As a result of these workarounds, reticle throughput is either reduced or sensitivity compromised when using binary database inspection algorithms on tritone reticles. This paper examines the benefits of using a tritone database inspection algorithm from both productivity and sensitivity standpoints as compared to results obtained from using the aforementioned workarounds and existing binary inspection modes. The results and conclusions contained within are based on data obtained from standard test vehicles and a variety of tritone production reticles.

Paper Details

Date Published: 20 October 2006
PDF: 11 pages
Proc. SPIE 6349, Photomask Technology 2006, 63493L (20 October 2006); doi: 10.1117/12.686121
Show Author Affiliations
Bryan Reese, KLA-Tencor Corp. (United States)
Jan Heumann, Advanced Mask Technology Ctr. (Germany)
Norbert Schmidt, KLA-Tencor Corp. (Germany)

Published in SPIE Proceedings Vol. 6349:
Photomask Technology 2006
Patrick M. Martin; Robert J. Naber, Editor(s)

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