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This article describes a frame for protecting ultra-thin ultraviolet light transparent pellicles against damage during handling and particularly during insertion and removal in the exposure tool.
English (United States)
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Protective Cover for Pellicles in a Projection Printing System
This article describes a frame for protecting ultra-thin ultraviolet light
transparent pellicles against damage during handling and particularly during
insertion and removal in the exposure tool.
U.S. Patent 4,131,363 describes the use of a transparent film or pellicle to
protect a projection printing mask against physical damage and the deposition of
particles. The pellicle was displaced from the mask so as to be out of focus and
thus would not interfere with the clarity of the projection. Typically the mask was
made of a tough MYLAR* film.
MYLAR is non-transparent to ultraviolet light. Therefore, if this typically ultra-
thin quartz. While optically satisfactory, the quartz pellicle is extremely fragile
and must itself be protected.
A protective frame and sliding cover is shown in the drawing wherein the
mask plate 10 has attached pellicle frame 11, with pellicle film 12, provided with
ways 13 in which cover 14 slides to cover the pellicle for protection or, when
open, permit exposure. * Trademark of E. I. du Pont de Nemours & Co.
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