Method of and apparatus for washing photomask and washing solution for photomask

Abstract

Organic matter and metal impurities present on the surface of a photomask are removed. Foreign matter still adhering to the surface of the photomask is removed with H 2 gas dissolved water. The photomask is dried. Thus provided is a method of washing a photomask in a manner which permits attaining an effect of removing foreign matter equivalent or superior to that of a conventional method with a small amount of chemical solution and reducing the amounts of chemicals and high purity water.

What is claimed is:  
     
         1 . A method of washing a photomask comprising first to third steps of: 
 removing organic matter and metal impurities present on the surface of a photomask;    removing foreign matter adhering to said surface of said photomask with H 2  gas dissolved water; and    drying said photomask.    
     
     
         2 . The method of washing a photomask in accordance with    claim 1   , wherein said H 2  gas dissolved water is alkalized.  
     
     
         3 . The method of washing a photomask in accordance with    claim 2   , wherein said H 2  gas dissolved water is alkalized with ammonia.  
     
     
         4 . The method of washing a photomask in accordance with    claim 2   , wherein said H 2  gas dissolved water is alkalized with KOH.  
     
     
         5 . The method of washing a photomask in accordance with    claim 1   , also employing ultrasonics waves in said second step.  
     
     
         6 . The method of washing a photomask in accordance with    claim 5   , also employing ultrasonics waves in said first step of    claim 1   .  
     
     
         7 . The method of washing a photomask in accordance with    claim 5   , wherein said foreign matter is particulate foreign matter.  
     
     
         8 . An apparatus for washing a photomask comprising: 
 an acid tank for removing organic matter and metal impurities present on the surface of a photomask with a first washing solution;    a foreign matter removing tank for removing foreign matter adhering to said surface of said photomask with a second washing solution containing H 2  gas dissolved water;    a drying tank for drying said photomask;    first washing solution supply means supplying said first washing solution to said acid tank;    first control means provided on said first washing solution supply means for controlling the concentration and the temperature of said first washing solution;    second washing solution supply means supplying said second washing solution to said foreign matter removing tank; and    second control means provided on said second washing solution supply means for controlling the concentration and the temperature of said second washing solution.    
     
     
         9 . The apparatus for washing a photomask in accordance with    claim 8   , wherein said foreign matter removing tank is provided with ultrasonics waves application means for supplying ultrasonic waves into said foreign matter removing tank.  
     
     
         10 . The apparatus for washing a photomask in accordance with    claim 8   , wherein said acid tank is provided with ultrasonics waves application means for supplying ultrasonic waves into said acid tank.  
     
     
         11 . The apparatus for washing a photomask in accordance with    claim 8   , further comprising aqueous ammonia supply means provided in said foreign matter removing tank for supplying aqueous ammonia of prescribed concentration into said foreign matter removing tank.  
     
     
         12 . A washing solution for a photomask containing H 2  gas dissolved water.  
     
     
         13 . The washing solution for a photomask in accordance with    claim 12   , wherein said H 2  gas dissolved water is alkalized.  
     
     
         14 . The washing solution for a photomask in accordance with    claim 13   , wherein said H 2  gas dissolved water is alkalized with ammonia.  
     
     
         15 . The method of washing a photomask in accordance with    claim 1   , wherein said photomask includes a halftone phase-shift photomask formed with an MoSiON film.