Gas discharge laser light source beam delivery unit

Abstract

A beam delivery unit and method of delivering a laser beam from a laser light source for excimer or molecular fluorine gas discharge laser systems in the DUV and smaller wavelengths is disclosed, which may comprise: a beam delivery enclosure defining an output laser light pulse beam delivery path from an output of a gas discharge laser to an input of a working apparatus employing the light contained in the output laser light pulse beam; a purge mechanism operatively connected to the beam delivery enclosure; an in-situ beam parameter monitor and adjustment mechanism within the enclosure, comprising a retractable beam redirecting optic; a beam analysis mechanism external to the enclosure; and, a retraction mechanism within the enclosure and operable from outside the enclosure and operative to move the retractable beam redirecting optic from a retracted position out of the beam path to an operative position in the beam path. The BDU may also include a beam attenuator unit contained within the enclosure adjustably mounted within the enclosure for positioning within the beam delivery path. The BDU may have at least two enclosure isolation mechanisms comprising a first enclosure isolation mechanism on a first side of the enclosure from the at least one optic module and a second enclosure isolation mechanism on a second side of the enclosure from the at least one optic module, each respective enclosure isolation mechanism comprising a flapper valve having a metal to metal seating mechanism and a locking pin assembly. A precision offset ratchet driver operative to manipulate actuator mechanisms in difficult to reach locations may be provided. An external kinematic alignment tool may be provided. A method of contamination control for a BDU is disclosed comprising selection of allowable materials and fabrication processes.

1 . A method of contamination control for a beam delivery unit for a manufacturing process UV laser light source, comprising: 
 providing a beam delivery enclosure defining an output laser light pulse beam delivery path from an output of a gas discharge laser to an input of a working apparatus employing the light contained in the laser light output pulse beam;    selecting metal materials for elements within the enclosure exclusively from a group consisting of:    bare metals: 
 aluminum, copper, tin, inconel, nickle and alloys of brass, stainless steel and invar;  
   metals for fabrication: 
 for enclosures: 
 6061-T651 aluminum per ASME SB-209 or SB-11, with certification of conformance;  
 
 for other fabrication uses: 
 aluminum 6061-T651 aluminum per ASME SB-209 or SB-11, with certification of conformance, and stainless steel type UNS 302,  
 
 UNS 340 and UNS 316L; and  
   Other metals: 
 Titanium or Ti-6al-4V.  
   
     
     
         2 . A method of contamination control for a beam delivery unit for a manufacturing process UV laser light source, comprising: 
 providing a beam delivery enclosure defining an output laser light pulse beam delivery path from an output of a gas discharge laser to an input of a working apparatus employing the light contained in the laser light output pulse beam;    selecting metal materials for elements within the enclosure exclusively that have finishing selected from a group consisting of:    Surface finishes: 
 at least Ra 32 before plating for all purged surfaces whether or not exposed to UV light;  
 electro-less nickel plating; and  
 thin dense chrome plating.  
   
     
     
         3 . The method of  claim 1  further comprising: 
 excluding from the enclosure any elements comprising any of the following materials except those included in the groups consisting of:    glasses: 
 pyrex, fuesd silica, schott filter glasses, ULE and zerodur;  
   crystals: 
 calcium fluoride, magnesium fluoride, quartz and sapphire;  
   ceramics: 
 high density, non porous, alumina, lucalux, silcon nitride and lead zirconate titanate; and  
   VUV foil.    
     
     
         4 . The method of  claim 2  further comprising: 
 excluding from the enclosure any elements comprising any of the following materials except those included in the groups consisting of:    glasses: 
 pyrex, fuesd silica, schott filter glasses, ULE and zerodur;  
   crystals: 
 calcium fluoride, magnesium fluoride, quartz and sapphire;  
   ceramics: 
 high density, non porous, alumina, lucalux, silcon nitride and lead zirconate titanate; and  
   VUV foil.    
     
     
         5 . The method of  claim 2  further comprising: 
 utilizing for uniting elements within the enclosure exclusively soldering or welding selected from the group consisting of, respectively:    fillerless, fusion ob base metals only; and    flux-less, tin and lead only.    
     
     
         6 . The method of  claim 3  further comprising: 
 utilizing for uniting elements within the enclosure exclusively soldering or welding selected from the group consisting of, respectively:    fillerless, fusion ob base metals only; and    flux-less, tin and lead only.    
     
     
         7 . The method of  claim 4  further comprising: 
 utilizing for uniting elements within the enclosure exclusively soldering or welding selected from the group consisting of, respectively:    fillerless, fusion ob base metals only; and    flux-less, tin and lead only.    
     
     
         8 . The method of  claim 5  further comprising: 
 utilizing for uniting elements within the enclosure exclusively soldering or welding selected from the group consisting of, respectively:    fillerless, fusion ob base metals only; and    flux-less, tin and lead only.