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;        detecting image information of the secondary beam using a time delay integration array charge coupled device sensor, the sensor having a plurality of lines each of which contains a plurality of pixels; and        transferring signal charges accumulated in one of the lines to an adjacent line in correspondence with driving a stage or a voltage applied to a deflector which deflects the secondary beam.     
     
     
       8. 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. 
     
     
       9. 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;        detecting image information of the secondary beam to acquire an image of an entire surface of the object using a time delay integration array charge coupled device sensor, the sensor having a plurality of lines each of which contains a plurality of pixels, wherein signal charges accumulated in one of the lines are transferred to an adjacent line in correspondence with driving a stage;        specifying a defective region of the object by template matching with a template image;        detecting image information of the secondary beam to acquire an enlarged image of the defective region using the time delay integration array charge coupled device sensor, wherein signal charges accumulated in one of the lines are transferred to an adjacent line in correspondence with driving a voltage applied to a deflector which deflects the secondary beam.     
     
     
       10. The method of  claim 9 , wherein the number of pixels in the region of the object corresponds to the number of pixels in the sensor. 
     
     
       11. 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;        converting electrons emitted from the region of the object into light;        detecting image information of the light using a time delay integration array charge coupled device sensor, the sensor having a plurality of lines each of which contains a plurality of pixels; and        transferring signal charges accumulated in one of the lines to an adjacent line in correspondence with driving a stage or a voltage applied to a deflector which deflects the secondary beam.     
     
     
       12. The method of  claim 11 , wherein the number of pixels in the region of the object corresponds to the number of pixels in the sensor. 
     
     
       13. 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;        converting electrons emitted from the region of the object into light;        detecting image information of the light to acquire an image of an entire surface of the object using a time delay integration array charge coupled device sensor, the sensor having a plurality of lines each of which contains a plurality of pixels, wherein signal charges accumulated in one of the lines are transferred to an adjacent line corresponding to a driving of a stage;        specifying a defective region of the object by template matching with a template image;        detecting image information of the light to acquire an enlarged image of the defective region using the time delay integration array charge coupled device sensor, wherein signal charges accumulated in one of the lines are transferred to an adjacent line in correspondence with driving a voltage applied to a deflector which deflects the secondary beam.     
     
     
       14. 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. 
     
     
       15. An object observation apparatus, comprising:
   a stage for placing an object;        a stage driver;        an irradiation optical system for irradiating a region of the object with a primary electron beam;        an electron detector for detecting image information of a secondary beam generated from the region of the object, the region of the object comprising a plurality of pixels; and        a deflector arranged between the object and the electron detector for deflecting the secondary beam;        wherein the electron detector comprises:      a time delay integration array charge coupled device sensor having a plurality of lines, each line containing a plurality of pixels; and        a controller connected to the time delay integration array image charge coupled device sensor for transferring signal charges accumulated in one of the lines to an adjacent line in accordance with driving the stage by the stage driver or a voltage applied to the deflector for deflecting the secondary beam.       
     
     
       16. An object observation apparatus, comprising:
   a stage for placing an object;        a stage driver;        an irradiation optical system for irradiating a region of the object with a primary electron beam;        an electron detector for detecting image information of a secondary beam generated from the region of the object, and the electron detector comprising a time delay integration array charge coupled device sensor having a plurality of lines, each line containing a plurality of pixels, and a controller connected to the time delay integration array charge coupled device sensor for transferring signal charges accumulated in one of the lines to an adjacent line;        a deflector arranged between the object and the electron detector for deflecting the secondary beam; and        a specifying unit for receiving image information of an entire surface of the object and specifying a defective region of the object by template matching with a template image;        wherein the controller transfers the signal charges in accordance with driving the stage by the stage driver to acquire the image information of the entire surface of the object and a voltage applied to the deflector for deflecting the secondary beam to acquire an enlarged image of the defective region of the object.     
     
     
       17. An object observation apparatus, comprising:
   a stage for placing an object;        a stage driver;        an irradiation optical system for irradiating a region of the object with a primary electron beam;        an electron detector for detecting image information of a secondary beam generated from the region of the object, and the electron detector comprising a fluorescent unit for converting the secondary beam into light, a time delay integration array charge coupled device sensor having a plurality of lines, each line containing a plurality of pixels, and a controller connected to the time delay integration array charge coupled device sensor for transferring signal charges accumulated in one of the lines to an adjacent line;        a deflector arranged between the object and the electron detector for deflecting the secondary beam; and        a specifying unit for receiving image information of an entire surface of the object and specifying a defective region of the object by template matching with a template image;        wherein the controller transfers the signal charges in accordance with driving the stage by the stage driver to acquire the image information of the entire surface of the object and a voltage applied to the deflector for deflecting the secondary beam to acquire an enlarged image of the defective region of the object.