In-tool and Out-of-Tool Protection of Extreme Ultraviolet (EUV) Reticles

Abstract

A reticle carrier for an Extreme Ultraviolet (EUV) reticle may include nested grids of electret fibers to provide active protection from contamination without a power supply. The reticle carrier may include in-line sensors for in-situ monitoring of contamination. Grids of electret fibers may also be used in an EUV pellicle.

1 . A reticle carrier comprising:
 a plurality of walls, each wall having an interior side and an exterior side, wherein the interior sides of the walls are arranged to define a sealable cavity;   a reticle holder disposed within the cavity   a sensor within said cavity, wherein said sensor is to sensitive to a property of particles in the cavity; and   an output to convey particle information from the sensor out of the cavity of the reticle carrier.   
     
     
         2 . The reticle carrier of  claim 1 , wherein the sensor comprises a mass sensor. 
     
     
         3 . The reticle carrier of  claim 2 , wherein the mass sensor comprises a quartz crystal microbalance. 
     
     
         4 . The reticle carrier of  claim 2 , wherein the mass sensor comprises a surface acoustic wave (SAW) sensor. 
     
     
         5 . The reticle carrier of  claim 1 , wherein the sensor is mounted on a first interior side of one of said plurality of walls. 
     
     
         6 . The reticle carrier of  claim 1 , wherein the sensor comprises a surface coating having a high sticking coefficient for the particles to be monitored. 
     
     
         7 . The reticle carrier of  claim 1 , further comprising a first plurality of electret fibers within the cavity. 
     
     
         8 . The reticle carrier of  claim 7 , further comprising a second plurality of electret fibers within the cavity, wherein first plurality of electret fibers is arranged in a first layer and the second plurality of electret fibers is arranged in a second layer. 
     
     
         9 . The reticle carrier of  claim 8 , wherein:
 the reticle holder is positioned to hold a patterned side of a reticle facing the first layer of the first plurality of electret fibers.   
     
     
         10 . The reticle carrier of  claim 1 , further comprising a funnel disposed between the reticle holder and the sensor. 
     
     
         11 . A device comprising:
 a debris trap dimensioned to be positionable between an illumination source and a reticle in a lithography system, wherein the debris trap comprises a frame and a plurality of electret fibers attached to the frame.   
     
     
         12 . The device of  claim 11 , further comprising an extreme ultraviolet lithography system. 
     
     
         13 . The device of  claim 11 , wherein the debris trap comprises a pellicle. 
     
     
         14 . The device of  claim 11 , wherein the plurality of electret fibers are incorporated into a grid including a first layer of electret fibers and a second layer of electret fibers. 
     
     
         15 . The device of  claim 14 , wherein the electret fibers in the first layer and the electret fibers in the second layer are arranged in a staggered orientation. 
     
     
         16 . The device of  claim 11 , wherein the electret fibers have a thickness of about 50 μm. 
     
     
         17 . The device of  claim 11 , wherein the electret fibers have a dipole field with a polarity of about 10 nC/cm 2 . 
     
     
         18 . The device of  claim 11 , wherein adjacent electret fibers in the plurality of electret fibers are spaced apart by about 1 mm. 
     
     
         19 . The device of  claim 11 , wherein the plurality of said electret fibers are aligned with dipole fields in a minimum energy configuration. 
     
     
         20 . A lithography system comprising:
 a plurality of walls, each wall having an interior side and an exterior side, wherein the interior sides of the walls are arranged to define a sealable chamber that is dimensioned to receive a reticle;   a reticle holder within the chamber, wherein the reticle holder is dimensioned to hold a patterning face of a reticle facing a first direction;   a frame holder; and   a frame having a plurality of electret fibers attached thereto,   wherein the frame holder is positioned to hold the