Container for framed pellicle

Abstract

The invention provides an improvement in a pellicle container for containing a framed pellicle conventionally made from a plastic resin, which is mounted on a photolithographic photomask for dust-proof protection thereof. A serious problem in the plastic resin-made container is adsorption or deposition of organic matters emitted from the container body by or on the pellicle membrane during storage or transportation resulting in a decrease in the light transmission as well as accelerated degradation of the pellicle membrane to the light of an extremely short wavelength for patternwise exposure in the photolithography while this problem can be solved by the improvement of the invention according to which at least the surface layer of the container surfaces facing the space for containing the framed pellicle is formed from an inorganic material, e.g., metals, glass materials and ceramics, free from emission of any organic matters.

What is claimed is:  
     
         1 . In a container for a framed pellicle as an assembly of a container base and a covering mountable on the container base jointly to form an inside space for containing a framed pellicle, the improvement which comprises forming at least the surface layer of the container base and the covering facing the inside space from an inorganic material selected from the group consisting of metals or alloys, glass materials and ceramic materials to form a cladding layer.  
     
     
         2 . The improvement as claimed in    claim 1    in which the container base and the covering of the container are entirely formed from the inorganic material.  
     
     
         3 . The improvement as claimed in    claim 1    in which the cladding layer of an inorganic material is formed only on the surfaces of the container base and the covering made from a plasyic resin facing the inside space.  
     
     
         4 . The improvement as claimed in    claim 1    in which the cladding layer of an inorganic material is formed both on the surfaces of the container base and the covering made from a plastic resin facing the inside space and on the outwardly facing surfaces thereof.  
     
     
         5 . The improvement as claimed in    claim 1    in which the cladding layer of an inorganic material has a thickness of at least 0.1 μm.  
     
     
         6 . The improvement as claimed in    claim 1    in which the metal or alloy forming the cladding layer is selected from the group consisting of aluminum, copper, iron and stainless steels.  
     
     
         7 . The improvement as claimed in    claim 1    in which the ceramic material forming the cladding layer is selected from the group consisting of silicon nitride, silicon carbide, zirconia, alumina and boron nitride.