Laser produced plasma euv light source

Abstract

An EUV light source is disclosed that may include a laser source, e.g. CO 2 laser, a plasma chamber, and a beam delivery system for passing a laser beam from the laser source into the plasma chamber. Embodiments are disclosed which may include one or more of the following; a bypass line may be provided to establish fluid communication between the plasma chamber and the auxiliary chamber, a focusing optic, e.g. mirror, for focusing the laser beam to a focal spot in the plasma chamber, a steering optic for steering the laser beam focal spot in the plasma chamber, and an optical arrangement for adjusting focal power.

1 . An EUV light source comprising;
 a laser source;   a plasma chamber; and   a focusing mirror for focusing a laser beam from said laser source to a focal spot within said plasma chamber.   
     
     
         2 . An EUV light source as recited in  claim 1  wherein said focusing mirror is an off-axis parabolic mirror. 
     
     
         3 . An EUV light source as recited in  claim 1  wherein said focusing optic is moveable to selectively move the focal spot. 
     
     
         4 . An EUV light source as recited in  claim 3  further comprising a target delivery system for delivering a plasma source material to a plasma formation site in the plasma chamber. 
     
     
         5 . An EUV light source as recited in  claim 4  wherein said target delivery system comprises a droplet generator. 
     
     
         6 . An EUV light source as recited in  claim 4  further comprising a target position detector for generating a signal indicative of target position. 
     
     
         7 . An EUV light source as recited in  claim 6  wherein said focusing optic is moveable in response to said signal from said target position detector to locate the focal spot along a target trajectory. 
     
     
         8 . An EUV light source as recited in  claim 6  further comprising a steering optic disposed in said plasma chamber for steering the laser beam focal spot in said plasma chamber. 
     
     
         9 . An EUV light source as recited in  claim 8  wherein said steering optic and said focusing optic are moveable together in a first direction to move the focal spot along a path parallel to the first direction. 
     
     
         10 . An EUV light source as recited in  claim 8  wherein said steering optic is independently moveable in two dimensions. 
     
     
         11 . An EUV light source as recited in  claim 8  wherein said steering optic is moveable in response to said signal from said target position detector to locate the focal spot along a target trajectory. 
     
     
         12 . An EUV light source comprising;
 a laser source;   a plasma chamber;   a focusing optic for focusing a laser beam from said laser source to a focal spot within said plasma chamber; and   an actuator moving said focusing optic to selectively move the focal point within the plasma chamber.   
     
     
         13 . An EUV light source as recited in  claim 12  further comprising a target position detector for generating a signal indicative of target position and wherein said focusing optic is moveable in response to said signal from said target position detector to locate the focal spot along a target trajectory. 
     
     
         14 . An EUV light source as recited in  claim 12  further comprising a steering optic for steering the laser beam focal spot in said plasma chamber and wherein said steering optic and said focusing optic are moveable together in a first direction to move the focal spot along a path parallel to the first direction. 
     
     
         15 . An EUV light source comprising;
 a laser source;   a plasma chamber;   a focusing optic for focusing a laser beam from said laser source to a focal spot within said plasma chamber; and   an optical assembly to adjust a focal power of said focal spot.   
     
     
         16 . An EUV light source as recited in  claim 15  wherein said optical assembly comprises a z-fold telescope. 
     
     
         17 . An EUV light source as recited in  claim 16  wherein said z-fold telescope comprises two spherical mirrors. 
     
     
         18 . An EUV light source as recited in  claim 15  wherein said focusing optic is a mirror. 
     
     
         19 . An EUV light source as recited in  claim 15  further comprising a conical shroud positioned in said chamber to at least partially shield said focusing optic from debris generated in said plasma chamber. 
     
     
         20 . An EUV light source as recited in  claim 19  further comprising a system for flowing a gaseous etchant in said shroud. 
     
     
         21 . An LPP EUV light source comprising:
 a laser source generating a laser beam;   a source material droplet generator to generate droplets for exposure to said laser beam and produce an EUV emission;   a detector for measuring an angular EUV emission distribution and outputting a signal indicative thereof; and   a control system responsive to said signal to increase a coupling between said laser beam and said droplets.