| 摘要 |
A pellicle which reduces the number of particles that migrate onto a stepping field of the mask is disclosed. The pellicle frame in a preferred embodiment has an inner and an outer wall. The pressure relief system has an indirect air path which reduces the chance of particle migration from outside the frame to the protected area. The pellicle membrane is attached to the top of the outer wall and stretches over the rounded top of the inner wall, which has a slightly greater height than the outer wall. The reticle is attached to the bottom of the outer wall, while the bottom of the inner wall is sealed against the reticle with an O-ring. In this way, none of the adhesives used to attach the frame to the membrane or to the reticle are in direct contact with the protected area of the reticle. The pressure relief system allows for equalization of pressure between the area protected by the pellicle and atmospheric pressure with a reduced chance of particle migration. The outer wall has one or more conduits between the outside of the frame to a channel between the two walls. The inner wall also has one or more conduits from the channel to the protected area. The conduits in the inner wall are on the opposite side of the frame from the conduits in the outer wall of the frame.
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