摘要 |
There is provided a pellicle having a rectangular pellicle frame formed of four side bars, having a through hole made through at least one of the frame bars for adjusting a pressure of a space formed within the pellicle frame equal to a pressure outside the pellicle frame; and a filter member disposed to cover up an external opening of the through hole for preventing entrance of particles into the space, wherein the through hole is formed with: (1) an outer stepped portion defining a first recess, opening outside the pellicle frame, for accommodating the filter member, (2) an inner stepped portion defining a second recess, opening in a bottom of the first recess, and (3) a ventilation hole with one end opening in a bottom of the second recess of the inner stepped portion and the other end opening in the space within the pellicle frame.
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