18 December 1998 Use of KLA-Tencor STARlight SL 300 for in-process contamination inspection to control reticle defect densities
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Control of defects on photomasks is becoming increasingly critical with smaller geometries, tighter specifications and optical proximity control (OPC). Additionally there are new phase shift (PSM) mask materials which are difficult, if not impossible to repair with today's equipment. This paper reports on using the KLA-Tencor STARlight SL 300 in several applications to improve first pass defect levels on photomasks. Two tests were run in which fully exposed reticles were inspected at several points in the PBS process to determine which process caused hard chrome defects at final inspection. In the first test, of 23 final defects, 9 were first seen after exposure (presumed on the raw blank), 2 after develop and 12 after bake. In the second, of 9 final defects, 6 were seen on raw blank, 1 after exposure and 2 after develop. Also reported is the use of the SL 300 to assist in an iterative process/equipment improvement for a strip cycle, resulting in 0 post strip defects in clear areas greater than or equal to 0.5 micrometer. Finally, raw mask blank inspection prior to writing is discussed. Data is presented on a lot of 10 plates in which 50% of the plates inspected did not meet the specification of 0 defects greater than or equal to 1.0 micrometer. The use of the SL 300 to 'cherrypick' blanks for difficult layers is discussed.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Duane Dutton, Duane Dutton, Wayne P. Shen, Wayne P. Shen, Richard Yee, Richard Yee, James A. Reynolds, James A. Reynolds, } "Use of KLA-Tencor STARlight SL 300 for in-process contamination inspection to control reticle defect densities", Proc. SPIE 3546, 18th Annual BACUS Symposium on Photomask Technology and Management, (18 December 1998); doi: 10.1117/12.332817; https://doi.org/10.1117/12.332817

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