Mask repair with electron beam-induced chemical etching

Abstract

The present invention discloses a method of fabricating and repairing a mask without damage and an apparatus including a holder to mount a substrate; a stage to position the holder in a chamber; a pumping system to evacuate the chamber; an imaging system to locate an opaque defect in the substrate; a gas delivery system to dispense a reactant gas towards the defect; and an electron delivery system to direct electrons towards the opaque defect.

We claim:  
     
         1 . An apparatus comprising: 
 a holder adapted to mount a substrate;    a stage adapted to position said holder in a chamber;    a pumping system adapted to evacuate said chamber;    an imaging system adapted to locate an opaque defect in said substrate;    a gas delivery system adapted to dispense a reactant gas towards said defect; and    an electron delivery system adapted to direct electrons towards said opaque defect.    
     
     
         2 . The apparatus of  claim 1  wherein said imaging system comprises an electron column.  
     
     
         3 . The apparatus of  claim 1  wherein said electron delivery system comprises an electron column.  
     
     
         4 . The apparatus of  claim 1  wherein said substrate comprises a transmissive DUV mask.  
     
     
         5 . The apparatus of  claim 1  wherein said opaque defect comprises chrome and said reactant gas comprises chlorine and oxygen.  
     
     
         6 . The apparatus of  claim 1  wherein said substrate comprises a reflective EUV mask.  
     
     
         7 . The apparatus of  claim 1  wherein said opaque defect comprises an absorber and said reactant gas comprises Xenon Fluoride (XeF 2 ).  
     
     
         8 . The apparatus of  claim 1  wherein said opaque defect comprises Carbon and said reactant gas comprises water vapor or oxygen.  
     
     
         9 . The apparatus of  claim 1  further comprising a focusing system adapted to highly focus said electrons on said opaque defect.  
     
     
         10 . The apparatus of  claim 1  further comprising a scanning system adapted to scan said electrons across said opaque defect.  
     
     
         11 . The apparatus of  claim 1  further comprising an acceleration system adapted to provide a low acceleration voltage for said electrons.  
     
     
         12 . The apparatus of  claim 1  further comprising a computer adapted to control said electron delivery system.  
     
     
         13 . A method comprising: 
 providing a substrate;    forming a layer over said substrate;    patterning said layer into a first region and a second region;    removing said layer in said first region;    inspecting said first region for an opaque defect;    forming a reactant gas over said opaque defect; and    directing electrons toward said opaque defect, said electrons inducing said reactant gas to etch said opaque defect.    
     
     
         14 . The method of  claim 13  wherein said reactant gas etches said opaque defect without damage to said substrate.  
     
     
         15 . The method of  claim 13  wherein said opaque defect comprises chrome and said reactant gas comprises chlorine and oxygen.  
     
     
         16 . A method comprising: 
 providing a substrate;    forming a mirror over said substrate;    forming a buffer layer over said mirror;    forming an absorber layer over said buffer layer;    patterning said absorber layer into a first region and a second region;    removing said absorber layer in said first region;    inspecting said first region for an opaque defect;    dispensing a reactant gas over said opaque defect;    scanning an electron beam over said opaque defect, said electron beam inducing said reactant gas to react with said opaque defect to form a volatile byproduct; and    removing said buffer layer in said first region.    
     
     
         17 . The method of  claim 16  wherein said opaque defect comprises an absorber and said reactant gas comprises Xenon Fluoride (XeF 2 ).