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4 November 2005 Haze prevention and phase/transmission preservation through cleaning process optimization
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Several haze studies were conducted in a test environment where UV lamps and test chambers were used to simulate a wafer fab environment. This study was designed to investigate reticles experiencing different cleaning processes in a real wafer production environment. A split test was carried out to benchmark two different fabs: an 8" R & D fab and an 8" memory production fab. Reticles cleaned with UV treatment and hot DI water were exposed on ArF scanners for up to 80 hours over a period of two months. Starlight inspection before and after laser exposure confirmed no significant defect count increase after exposure. Ion chromatography (IC) results from masks cleaned on a new Steag MaskTrack cleaner suggest that hydrogenated water (H2-H2O) and ozonated water (O3-H2O) processes can further reduce the sulfate and ammonium ion residual count by 40%. UV + hot water cleaning also shows advantages in phase and transmission preservation where less than a 0.2 degree phase angle loss per clean can be achieved.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jennifer Qin, Yuan Zhang, Rob Delgado, Barry Rockwell, Florence Tan, Khoi Phan, Lothar Berger, Min Liu, and Uwe Dietez "Haze prevention and phase/transmission preservation through cleaning process optimization", Proc. SPIE 5992, 25th Annual BACUS Symposium on Photomask Technology, 59921E (4 November 2005);


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