Photomask Pellicle Support Ring Design
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
A problem is sometimes caused by the bonding of a photomask pellicle to the support ring. The adhesive that is used for the bonding is drawn into the inner surface of the ring, forms a meniscus at the film ring interface, and hardens into a ridge. If the assembly receives a mechanical shock or any subsequent pressure after the bonding agent has hardened, it can break free and move to the mask plate, causing a printable defect. The solution to this problem is the incorporation of a groove 1 on the top surface of the pellicle ring 2. When the bonding agent 4 is applied to the pellicle ring 2 on the outer land and the film 3 is attached, the groove 1 stops the spreading of the bonding agent 4 before it gets to the inner surface and can contaminate the mask plate.