Rotational stage for high speed, large area scanning in focused beam systems

Abstract

A mechanical scanning stage for high speed image acquisition in a focused beam system. The mechanical scanning stage preferably is a combination of four stages. A first stage provides linear motion. A second stage, above the first stage, provides rotational positioning. A third stage above the rotational stage is moveable in a first linear direction, and the fourth stage above the third stage is positionable in a second linear direction orthogonal to the first direction. The four stages are responsive to input from a controller programmed with a polar coordinate pixel addressing method, for positioning a specimen mounted on the mechanical stage to allow an applied static focus beam to irradiate selected areas of interest, thereby imaged by collecting signals from the specimen using a polar coordinate pixel addressing method.

1. A method of scanning a specimen in an image acquisition system comprising:
 (a) placing a specimen on a mechanical stage for positioning and scanning said specimen for irradiation by an energy beam; 
 (b) first moving said specimen along a first axis by a first stage of said mechanical stage providing linear positioning and scanning movement; 
 (c) second moving said specimen by a second stage of said mechanical stage providing scanning rotational movement; and 
 (d) impacting said specimen with a non-scanning energy beam, whereby the image is acquired during the scanning movements of the stages. 
 
     
     
       2. A method as recited in  claim 1  further comprising directing movement of said mechanical stage by a controller. 
     
     
       3. A method as recited in  claim 2  wherein said controller directs said scanning of said specimen by directing said first stage to sequentially position said specimen at each of a plurality of steps, and directs said second stage to sequentially rotate to a plurality of rotational positions for each said step. 
     
     
       4. A method as recited in  claim 1  further comprising:
 (a) third moving said specimen by a third stage providing linear movement in an X direction; and 
 (b) fourth moving said specimen by a fourth stage providing linear movement in a Y direction orthogonal to said X direction. 
 
     
     
       5. A method as recited in  claim 4  wherein said third and fourth stages are for initial positioning of said specimen. 
     
     
       6. A method as recited in  claim 1  further comprising third moving said specimen by a third stage providing linear movement orthogonal to said first axis. 
     
     
       7. A method as recited in  claim 6  wherein said first stage is for scanning, and said third stage is for specimen positioning and is mounted on top of said second stage. 
     
     
       8. A method as recited in  claim 7  wherein said second stage is mounted on top of said first stage. 
     
     
       9. A method as recited in  claim 4  wherein said second stage is mounted on top of said first stage. 
     
     
       10. A method as recited in  claim 1  further comprising programming a controller to direct movement of said first and second stages so as to cause said first stage to move simultaneously with said second stage. 
     
     
       11. A method as recited in  claim 10  wherein said first and second stages are moved so as to address a location of interest on said specimen using spiral polar coordinates. 
     
     
       12. A method of scanning a specimen in an image acquisition system comprising:
 moving said specimen along a first axis by a first stage of a mechanical stage providing linear positioning and scanning movement;   moving said specimen by a second stage of said mechanical stage providing scanning rotational movement; and   impacting said specimen with a non-scanning energy beam, wherein the image is acquired during the scanning movements of the first and second stages.    
     
     
       13. The method as recited in claim 12 further comprising directing movement of said mechanical stage by a controller.  
     
     
       14. The method as recited in claim 12, and further comprising:
 directing said scanning of said specimen by directing said first stage to sequentially position said specimen at each of a plurality of steps; and   directing said second stage to sequentially rotate to a plurality of rotational positions for each said step.    
     
     
       15. The method as recited in claim 12, and further comprising:
 moving said specimen by a third stage providing linear movement in an X direction; and   moving said specimen by a fourth stage providing linear movement in a Y direction substantially orthogonal to said X direction.    
     
     
       16. The method as recited in claim 12, and further comprising moving said specimen by a third stage providing linear movement substantially orthogonal to said first axis.  
     
     
       17. The method as recited in claim 16, wherein said first stage is adapted for scanning, and said third stage is adapted for specimen positioning and is mounted on top of said second stage.  
     
     
       18. The method as recited in claim 17, wherein said second stage is mounted on top of said first stage.  
     
     
       19. A method as recited in claim 15 wherein said second stage is mounted on top of said first stage.  
     
     
       20. A method as recited in claim 12, and further comprising programming a controller to direct movement of said first and second stages so as to cause said first stage to move simultaneously with said second stage.  
     
     
       21. A method as recited in claim 20, wherein said first and second stages are moved so as to address a location of interest on said specimen using spiral polar coordinates.