1 June 1990 Characterization methods for excimer exposure of deep-UV pellicles
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A variety of instruments are used to monitor the aging of pellicles exposed to deep UV radiation including densitometry, VFIR spectroscopy, UV spectroscopy, and ellipsometry. By far the most useful measurement is insitu transmission monitoring during exposure. A stable apparatus has been constructed and good lransmission versus dose data obtained for a variety of pellicle materials. Using a light pipe uniformer fed by a KrF excimer laser, dose rates up to 0.4W/cm2 can be obtained. Pellicle transmission changes due to optical thickness changes, ablation of AR-coatings, and increased bulk absorption have been observed (in typical oder of importance). SpectrOscopy is used to extract a pellicle's refractive index and physical thickness after various stages of exposure. It has been found that the pellicle's physical thickness changes with exposure while it maintains an essentially constant refractive index. A method for measuring the pellicle's thickness during exposure has been developed. Through this method, is has been found that a dark reaction (continued thickness loss) occurs long after the deep-UV illumination is terminated.
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
William N. Partlo, William N. Partlo, William G. Oldham, William G. Oldham, } "Characterization methods for excimer exposure of deep-UV pellicles", Proc. SPIE 1264, Optical/Laser Microlithography III, (1 June 1990); doi: 10.1117/12.20210; https://doi.org/10.1117/12.20210


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