Phase shift mask blank, phase shift mask, and method of manufacture

Abstract

In a phase shift mask blank comprising a transparent substrate and a phase shift film thereon, after the phase shift film is formed on the substrate, it is surface treated with ozone water having an ozone concentration of at least 1 ppm. The resulting phase shift film is of quality in that it experiences minimized changes of phase difference and transmittance upon immersion in chemical liquid during subsequent mask cleaning step or the like.

1 . A phase shift mask blank comprising a transparent substrate and at least one layer of phase shift film thereon, wherein said phase shift film has been surface treated with ozone water having at least 1 ppm of ozone dissolved therein.  
     
     
         2 . A phase shift mask blank comprising a transparent substrate and at least one layer of phase shift film thereon, wherein said phase shift film is formed of a metal silicide oxide, metal silicide nitride or metal silicide oxynitride and then surface treated with ozone water having at least 1 ppm of ozone dissolved therein.  
     
     
         3 . A phase shift mask blank comprising a transparent substrate and at least one layer of phase shift film thereon, wherein said phase shift film is formed of molybdenum silicide oxide, molybdenum silicide nitride or molybdenum silicide oxynitride and then surface treated with ozone water having at least 1 ppm of ozone dissolved therein.  
     
     
         4 . The phase shift mask blank of  claim 2  wherein said phase shift film has an oxygen content and a silicon content at its surface, and a molar ratio of the oxygen content to the silicon content is at least 1.  
     
     
         5 . The phase shift mask blank of  claim 1  wherein said phase shift film changes the phase of exposure light passing therethrough by 180±5 degrees and has a transmittance of 3 to 40%.  
     
     
         6 . A phase shift mask obtained by patterning the phase shift film in the phase shift mask blank of  claim 1 .  
     
     
         7 . A method of manufacturing a phase shift mask blank comprising a transparent substrate and at least one layer of phase shift film thereon, 
 said method comprising the steps of forming the phase shift film on the substrate and surface treating the phase shift film with ozone water having at least 1 ppm of ozone dissolved therein.    
     
     
         8 . A method of manufacturing a phase shift mask blank comprising a transparent substrate and at least one layer of phase shift film thereon, 
 said method comprising the steps of forming the phase shift film of a metal silicide oxide, metal silicide nitride or metal silicide oxynitride on the substrate and surface treating the phase shift film with ozone water having at least 1 ppm of ozone dissolved therein.    
     
     
         9 . A method of manufacturing a phase shift mask blank comprising a transparent substrate and at least one layer of phase shift film thereon, 
 said method comprising the steps of forming the phase shift film of molybdenum silicide oxide, molybdenum silicide nitride or molybdenum silicide oxynitride on the substrate and surface treating the phase shift film with ozone water having at least 1 ppm of ozone dissolved therein.    
     
     
         10 . The method of manufacturing a phase shift mask blank of  claim 7  wherein said phase shift film changes the phase of exposure light passing therethrough by 180±5 degrees and has a transmittance of 3 to 40%.  
     
     
         11 . A method of manufacturing a phase shift mask, comprising the steps of 
 forming by photolithography a patterned resist film on the phase shift film in the phase shift mask blank obtained by the method of  claim 7 ,    etching away the portions of the phase shift mask which are uncovered with the resist film, and    thereafter, removing the resist film.