Method for purification of lens gases used in photolithography

Abstract

A method and composition for the removal of contaminants in a gas stream used in the contamination sensitive processes of photolithography and metrology are described. The synergistic effect of a combination of an electropositive metal component, a high silica zeolite, and a late transition metal compound effects removal or reduction of the contaminates in the gas which interfere with light transmittance to the ppb or ppt levels necessary for the gas to be suitable for these uses. The removal of neutral polar molecules, neutral polar aprotic molecules, protic and aprotic alkaline molecules, acidic polar species, and neutral non-polar aprotic molecules is accomplished with the claimed composition. Depending on the type of contaminant, the composition components are each varied from 10 to 80 parts by volume, with the total composition limited to 100 parts by volume.

1 . A method of decontaminating a gas, wherein said gas comprises one or more of neutral polar protic, neutral polar aprotic, alkaline and polar acidic contaminants, the method comprising removing said contaminants from the gas by passing the gas through a body of decontaminant comprising 10% to 80% by volume an electropositive metal component, 10% to 80% by volume of a late transition metal compound component and 10% to 80% by volume of a high silica zeolite component.  
     
     
         2 . The method of  claim 1 , wherein the decontaminant comprises a greater proportion of the electropositive metal component than the high silica zeolite component.  
     
     
         3 . The method of  claim 1 , wherein the decontaminant comprises a smaller proportion of high silica zeolite component than a combination of the electropositive metal component and the late transition metal compound component.  
     
     
         4 . The method of  claim 1 , wherein the gas comprises water or an alcohol contaminant.  
     
     
         5 . The method of  claim 4 , wherein the gas comprises a water contaminant.  
     
     
         6 . The method of  claim 5 , wherein the decontaminant comprises about 70% by volume of an electropositive metal component, about 15% by volume of a late transition metal component and about 15% of a high silica zeolite component.  
     
     
         7 . The method of  claim 1 , wherein the gas comprises a nitrogen oxide, a sulfur oxide, an organic sulfide or an alkyl halide contaminant.  
     
     
         8 . The method of  claim 7 , wherein the gas comprises a sulfur oxide or a nitrogen oxide contaminant.  
     
     
         9 . A method of decontaminating a gas, wherein said gas comprises one or more of alkaline, acidic polar, neutral non-polar aprotic and environmental gas contaminants, the method comprising removing said contaminants from the gas by passing the gas through a body of decontaminant comprising 10% to 80% by volume of a electropositive metal component, 10% to 80% by volume of a high silica zeolite component and 10% to 80% by volume of a late transition metal compound component.  
     
     
         10 . The method of  claim 9 , wherein the gas comprises an amine contaminant, an acid contaminant or both.  
     
     
         11 . The method of  claim 9 , wherein the gas comprises a siloxane contaminant, a hydrocarbon contaminant or both.  
     
     
         12 . The method of  claim 9 , wherein the decontaminant comprises a smaller proportion of electropositive metal component than a combination of the high silica zeolite component and the late transition metal compound component.  
     
     
         13 . The method of  claim 9 , wherein the decontaminant comprises a greater proportion of electropositive metal component than late transition metal component, and a greater proportion of high silica zeolite component than late transition metal component.