Apparatus for aligning a particle-beam-generated pattern to a pattern on a pre-patterned substrate

Abstract

The apparatus includes a particle beam, having an axis which functions as a primary optical axis, which particle beam is used to generate a pattern on a substrate. The apparatus also includes an optical reader, having an axis which functions as a secondary optical axis. A position fiducial is located at a stationary position relative to the substrate. Registration of a pre-existing pattern and the particle beam axis to the position fiducial periodically during production of a particle-beam-generated pattern continually provides an improvement in the overall alignment of the pattern being created with the pre-existing pattern on the substrate.

1 - 13 . (canceled) 
     
     
         14 . An apparatus used to align a particle-beam-generated pattern to a pre-existing pattern on a substrate, said apparatus comprising:
 a) a primary beam optical axis in the form of a particle beam axis, which particle beam is used to generate a pattern;   b) a secondary optical axis in the form of an optical reader axis;   c) a position fiducial located at a stationary position relative to said substrate; and   d) a controller adapted to control an operation of said particle beam and said optical reader axis, where said controller is adapted to calculate at least 3 vectors from said position fiducial to at least three alignment target locations on a substrate exhibiting a pre-existing pattern, where said vectors are determined using said secondary optical axis, and wherein said controller coordinates said at least 3 vectors with a location of said position fiducial measured by said primary beam optical axis, to conform said primary beam optical axis to an alignment with respect to said pre-existing pattern during writing of a particle-beam-generated pattern on said substrate.   
     
     
         15 . An apparatus in accordance with  claim 14 , wherein said particle beam is selected from the group consisting of an electron beam, an ion beam, a laser beam, a proton beam, a neutron beam, or an X-ray. 
     
     
         16 . An apparatus in accordance with  claim 15 , wherein said position fiducial is present on a stage on which said substrate is mounted. 
     
     
         17 . An apparatus in accordance with  claim 14 , wherein said position fiducial is present in a form of a grid. 
     
     
         18 . An apparatus in accordance with  claim 14 , wherein said position fiducial can be accurately measured by both an optical reader and a particle beam. 
     
     
         19 . An apparatus in accordance with  claim 14 , including means for registration of a pre-existing pattern to said position fiducial and means for registration of an optical axis of said particle beam to said position fiducial periodically during production of a pattern generated by said particle beam. 
     
     
         20 . An apparatus in accordance with  claim 18 , wherein said optical reader is an optical microscope and said particle beam is an electron beam. 
     
     
         21 . An apparatus in accordance with  claim 18 , wherein said position fiducial includes a transmission feature fabricated into silicon or metal. 
     
     
         22 . An apparatus in accordance with  claim 14  wherein an optical illumination used to implement said optical reader will not expose a photoresist which is sensitive to radiation from said particle beam. 
     
     
         23 . An apparatus in accordance with  claim 14 , where said controller is adapted to calculate from 3 alignment target locations up to about 16 alignment target locations. 
     
     
         24 . An apparatus in accordance with  claim 23 , wherein said calculated alignment target locations ranges in number from about 8 to about 16. 
     
     
         25 . An apparatus in accordance with  claim 14 , which includes an imager which sends scanned data for alignment target locations to said controller. 
     
     
         26 . An apparatus in accordance with  claim 25  where said imager sends digital data. 
     
     
         27 . An apparatus in accordance with  claim 25 , wherein said imager is a CMOS camera or a CCD camera. 
     
     
         28 . An apparatus in accordance with  claim 14 , wherein said particle beam which creates a pattern on said substrate also scans said position fiducial.