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Removable pellicle for lithographic mask protection and handling

United States Patent

December 10, 2002
View the Complete Patent at the US Patent & Trademark Office
Sandia National Laboratories - Visit the Intellectual Property Management and Licensing Website
A removable pellicle for a lithographic mask that provides active and robust particle protection, and which utilizes a traditional pellicle and two deployments of thermophoretic protection to keep particles off the mask. The removable pellicle is removably attached via a retaining structure to the mask substrate by magnetic attraction with either contacting or non-contacting magnetic capture mechanisms. The pellicle retaining structural is composed of an anchor piece secured to the mask substrate and a frame member containing a pellicle. The anchor piece and the frame member are in removable contact or non-contact by the magnetic capture or latching mechanism. In one embodiment, the frame member is retained in a floating (non-contact) relation to the anchor piece by magnetic levitation. The frame member and the anchor piece are provided with thermophoretic fins which are interdigitated to prevent particles from reaching the patterned area of the mask. Also, the anchor piece and mask are maintained at a higher temperature than the frame member and pellicle which also prevents particles from reaching the patterned mask area by thermophoresis. The pellicle can be positioned over the mask to provide particle protection during mask handling, inspection, and pumpdown, but which can be removed manually or robotically for lithographic use of the mask.
Klebanoff; Leonard E. (Dublin, CA), Rader; Daniel J. (Albuquerque, NM), Hector; Scott D. (Oakland, CA), Nguyen; Khanh B. (Sunnyvale, CA), Stulen; Richard H. (Livermore, CA)
EUV LLC (Santa Clara, CA)
09/ 454,674
December 3, 1999
GOVERNMENT RIGHTS The Government of the United States has rights in this invention pursuant to contract No. DE-ACO4-94AL85000 between the United States Department of Energy and the Sandia Corporation for the operation of the Sandia National Laboratories.