Object observation apparatus and object observation

Abstract

This invention relates to an object observation apparatus and observation method. The object observation apparatus is characterized by including a drivable stage on which a sample is placed, an irradiation optical system which is arranged to face the sample on the stage, and emits an electron beam as a secondary beam, an electron detection device which is arranged to face the sample, causes to project, as a primary beam, at least one of a secondary electron, reflected electron, and back-scattering electron generated by the sample upon irradiation of the electron beam, and generates image information of the sample, a stage driving device which is adjacent to the stage to drive the stage, and a deflector arranged between the sample and the electron detection device to deflect the secondary beam, the electron detection device having a converter arranged on a detection surface to convert the secondary beam into light, an array image sensing unit which is adjacent to the converter, has pixels of a plurality of lines each including a plurality of pixels on the detection surface, sequentially transfers charges of pixels of each line generated upon reception of light of an optical image obtained via the converter to corresponding pixels of an adjacent line at a predetermined timing, adds, every transfer, charges generated upon reception of light after the transfer at the pixels which received the charges, and sequentially outputs charges added up to a line corresponding to an end, and a control unit connected to the array image sensing unit to output a transfer signal for sequentially transferring charges of pixels of each line to an adjacent line, and the control unit having a stage scanning mode in which the array image sensing unit is controlled in accordance with a variation in projection position of the secondary beam projected on the electron detection device that is generated by movement of the stage device, and a deflector operation mode in which the array image sensing unit is controlled in accordance with a variation in projection position of the secondary beam projected on the detection device by the deflector.

1. An object observation apparatus comprising:
 a drivable stage on which a sample is placed;  
 an irradiation optical system which is arranged to face the sample on said stage, and emits an electron beam as a primary beam;  
 an electron detector which is arranged to face the sample, has a detection surface on which at least one of a secondary electron, a reflected electron, and a back-scattering electron generated by the sample upon irradiation of the electron beam is projected as a secondary beam, and generates image information of the sample;  
 a stage driver which is adjacent to said stage to drive said stage; and  
 a deflector arranged between the sample and said electron detector to deflect the secondary beam,  
 said electron detector having: 
 a converter arranged on the detection surface to convert the secondary beam into light;  
 an array image sensor which is adjacent to said converter, has pixels of a plurality of lines each including a plurality of pixels, sequentially transfers charges of pixels of each line generated upon reception of light of an optical image obtained via said converter to corresponding pixels of an adjacent line at a predetermined timing, adds, every transfer, charges generated upon reception of light after the transfer at the pixels which received the charges, and sequentially outputs charges added up to a line corresponding to an end; and  
 a controller connected to said array image sensor to output a transfer signal for sequentially transferring charges of pixels of each line to an adjacent line, and  
 
 said controller having: 
 a stage scanning mode in which said array image sensor is controlled in accordance with a variation in projection position of the secondary beam projected on said electron detector that is generated by movement of said stage device; and  
 a deflector operation mode in which said array image sensor is controlled in accordance with a variation in projection position of the secondary beam projected on said detector that is generated by operation of said deflector.  
 
 
     
     
       2. An object observation apparatus according to  claim 1 , further comprising a defect detector that detects a defective portion from the image information of the sample generated by said electron detector. 
     
     
       3. An object observation apparatus according to  claim 1 , wherein the electron beam has a rectangular or elliptic sectional shape. 
     
     
       4. An object observation method of observing an object using an electron beam, comprising:
 an irradiation step of irradiating the object on a stage with the electron beam;  
 a conversion step of projecting a secondary beam from the irradiated object onto a fluorescent portion, and converting the secondary beam into light at the fluorescent portion; and  
 an image sensing step of detecting image information of the light, converted at the fluorescent portion, with pixels of a plurality of lines each including a plurality of pixels, sequentially transferring charges generated in pixels of each line to corresponding pixels of an adjacent line at a predetermined timing, adding, every transfer, charges generated upon reception of light after the transfer at the pixels which received the charges, and sequentially outputting charges added up to a line corresponding to an end,  
 the image sensing step having: 
 a stage scanning mode in which a projection position of the secondary beam from the object moving with movement of the stage is varied; and  
 a deflector operation mode in which the projection position of the secondary beam from the object is varied by operating a deflector.  
 
 
     
     
       5. An object observation apparatus comprising:
 a drivable stage on which a sample is placed;  
 an irradiation optical system which is arranged to face the sample on said stage, and emits an electron beam;  
 an electron detector which is arranged to face the sample, has a detection surface on which at least one of a secondary electron, a reflected electron, and a back-scattering electron generated by the sample upon irradiation of the electron beam is projected as a secondary beam, and generates image information of the sample;  
 an electrooptic system arranged between the sample and said electron detector to form the secondary beam into an image on the detection surface of said electron detector; and  
 a position detector which is adjacent to said stage to detect a position of said stage,  
 said electron detector having: 
 a converter arranged on the detection surface to convert the secondary beam into light;  
 an array image sensor which is adjacent to said converter, has pixels of a plurality of lines each including a plurality of pixels, sequentially transfers charges of pixels of each line generated upon reception of light of an optical image obtained via said converter to corresponding pixels of an adjacent line at a predetermined timing, adds, every transfer, charges generated upon reception of light after the transfer at the pixels which received the charges, and sequentially outputs charges added up to a line corresponding to an end; and  
 a controller connected to said array image sensor to output a transfer signal for sequentially transferring charges of pixels of each line to an adjacent line,  
 said controller controlling said array image sensor using a detection signal from said position detector.  
 
 
     
     
       6. An object observation apparatus according to  claim 5 , further comprising:
 a deflector arranged between the sample and said electron detector to deflect the secondary beam; and  
 a deflector driver connected to said deflector to drive said deflector; and  
 said controller controls said array image sensor by selectively using the detection signal and a control signal from said deflector driver.  
 
     
     
       7. A method of observing an object using an electron beam, comprising:
   irradiating a region of an object with a primary electron beam, wherein a secondary beam is generated from the region of the object, the region of the object comprising a plurality of pixels; and        detecting image information of the secondary beam using a time delay integration array charge coupled device sensor, the sensor having a plurality of pixels.     
     
     
       8. The method of  claim 7 , wherein the primary electron beam has a rectangular or elliptic sectional shape. 
     
     
       9. The method of  claim 7 , wherein the number of pixels in the region of the object corresponds to the number of pixels in the sensor. 
     
     
       10. The method of  claim 7 , further comprising placing the object on a stage. 
     
     
       11. The method of  claim 10 , further comprising moving the stage and irradiating another region of the object. 
     
     
       12. The method of  claim 7 , further comprising deflecting the primary electron beam and irradiating another region of the object. 
     
     
       13. A method of observing an object using an electron beam, comprising:
   irradiating a region of an object with an electron beam, wherein electrons are emitted from the region of the object, the region of the object comprising a plurality of pixels;        converting electrons emitted from the region of the object into light; and        detecting image information of the light using a time delay integration array charge coupled device sensor, the sensor having a plurality of pixels.     
     
     
       14. The method of  claim 13 , wherein the electron beam has a rectangular or elliptic sectional shape. 
     
     
       15. The method of  claim 13 , wherein the number of pixels in the region of the object corresponds to the number of pixels in the sensor. 
     
     
       16. The method of  claim 13 , further comprising placing the object on a stage. 
     
     
       17. The method of  claim 16 , further comprising moving the stage and irradiating another region of the object. 
     
     
       18. The method of  claim 13 , further comprising deflecting the electron beam and irradiating another region of the object. 
     
     
       19. An object observation apparatus, comprising:
   means for generating a primary electron beam;        means for directing the primary electron beam to a region of an object, the region comprising a plurality of pixels; and        a time delay integration array charge coupled device sensor having a plurality of pixels and being positioned to detect image information of a secondary beam emitted from the region of the object.     
     
     
       20. The apparatus of  claim 19 , wherein the primary electron beam has a rectangular or elliptic sectional shape. 
     
     
       21. The apparatus of  claim 20 , wherein the means for generating the primary electron beam comprises an electron gun. 
     
     
       22. The apparatus of  claim 19 , wherein the number of pixels in the region of the object corresponds to the number of pixels in the sensor. 
     
     
       23. The apparatus of  claim 19 , further comprising a drivable stage for holding the object. 
     
     
       24. The apparatus of  claim 19 , further comprising means for deflecting the primary electron beam and thereby irradiating another region of the object.