Charged-particle microscope

Abstract

A charged-particle-beam device is characterized in having a control value for an aligner coil ( 29 ) being determined by: a coil current and an electrode applied-voltage at a control value for objectives ( 30, 31 ), which is an electromagnetic-field superposition lens; a control value for image-shift coils ( 27, 28 ); and the acceleration voltage of the charged-particle-beam. By doing this, it has become possible to avoid image disturbances that occur on images to be displayed at boundaries between charged areas and non-charged areas, and provide a charged-particle-beam device that obtains clear images without any unevenness in brightness.

1 . A charged particle microscope, comprising:
 a sample compartment in which a sample stage holding a sample to be measured is stored; and   a charged particle optical tube that detects and outputs a secondary signal generated by two-dimensionally scanning a charged particle beam onto the sample to be measured,   wherein the charged particle optical tube includes:   an objective lens that focuses the charged particle beam onto the sample to be measured;   a deflector that sets the center of the scanning in a desired position in a scanning area on the sample to be measured to which the charged particle beam is scanned;   an optical axis adjuster that reduces off-axis aberrations of the objective lens occurring when the charged particle beam is set in the center of the scanning area; and   an arithmetic processing device including: a setting value storing unit that stores a control value of the optical axis adjuster that controls the off-axis aberrations of the objective lens to be below a predetermined value; and a controller that controls control values of the objective lens, the deflector, and the optical axis adjuster,   the objective lens is an immersion lens configured by a plurality of lenses including an electromagnetic lens and an electrostatic lens, and   the setting value storing unit stores the control value of the optical axis adjuster determined by the control values of the electromagnetic lens and the electrostatic lens and the control value of the deflector.   
     
     
         2 . The charged particle microscope according to  claim 1 , wherein the deflector is configured by an image-shift deflector. 
     
     
         3 . The charged particle microscope according to  claim 1 , wherein the deflector is configured by an image-shift deflector and a scanning deflector. 
     
     
         4 . The charged particle microscope according to  claim 1 , wherein the sample stage includes:
 a supporting mechanism of the sample to be measured;   a height measuring device that measures a height of the sample to be measured; and   a unit that obtains a desired focusing condition by allowing the changed amount of the focal position of the objective lens according to the change in the height of the sample in the same sample to be measured to be followed by adjusting the electrostatic lens.   
     
     
         5 . The charged particle microscope according to  claim 4 , wherein the supporting mechanism of the sample to be measured is a supporting mechanism that uses an electrostatic chuck method. 
     
     
         6 . The charged particle microscope according to  claim 4 , further including:
 a unit that focuses the charged particle beam onto a desired focal position on the sample to be measured by applying a voltage to the sample to be measured and changing the voltage.   
     
     
         7 . A charged particle microscope, comprising:
 a sample compartment in which a sample stage holding a sample to be measured is stored; and   a charged particle optical tube that detects and outputs a secondary signal generated by two-dimensionally scanning a charged particle beam onto the sample to be measured,   wherein the charged particle optical tube includes:   an objective lens that focuses the charged particle beam onto the sample to be measured;   a deflector that sets the center of the scanning in a desired position in a scanning area on the sample to be measured to which the charged particle beam is scanned;   an optical axis adjuster that reduces off-axis aberrations of the objective lens occurring when the charged particle beam is set in the center of the scanning area; and   an arithmetic processing device including: a setting value storing unit that stores a control value of the optical axis adjuster that minimizes the off-axis aberrations of the objective lens; a first controller that controls control values of the objective lens, the deflector, and the optical axis adjuster; and a second controller that measures the deviation amount of the landing position of the sample to be measured of the charged particle beam that is generated when a voltage is applied to the sample to be measured and corrects the control value of the first controller based on the deviation amount, and   the setting value storing unit stores the control value of the optical axis adjuster determined by the control value of the objective lens and the control value of the deflector.   
     
     
         8 . The charged particle microscope according to  claim 7 , wherein the objective lens is an immersion lens configured by a plurality of lenses including an electromagnetic lens and an electrostatic lens. 
     
     
         9 . The charged particle microscope according to  claim 7 , wherein the sample stage includes:
 a supporting mechanism of the sample to be measured;   a height measuring device that measures a height of the sample to be measured; and   a unit that obtains a desired focusing condition by allowing the changed amount of the focal position of the objective lens according to the change in the height of the sample in the same sample to be measured to be followed by the adjustment of the electrostatic lens.   
     
     
         10 . The charged particle microscope according to  claim 7 , wherein the second controller controls the deflector in accordance with the obtained focusing condition to calculate a control condition that reduces the change in the observation position of an image to be obtained at the time of changing the focal position, and corrects the obtained focusing condition to a desired focusing condition based on the calculated control condition.