Charged-particle beam device for irradiating a charged particle beam on a sample
View Patent ↗The present invention explains a charged-particle beam device for the purpose of highly accurately measuring electrostatic charge of a sample in a held state by an electrostatic chuck ( 105 ). In order to attain the object, according to the present invention, there is proposed a charged-particle beam device including an electrostatic chuck ( 105 ) for holding a sample on which a charged particle beam is irradiated and a sample chamber ( 102 ) in which the electrostatic chuck ( 105 ) is set. The charged-particle beam device includes a potential measuring device that measures potential on a side of an attraction surface for the sample of the electrostatic chuck ( 105 ) and a control device that performs potential measurement by the potential measuring device in a state in which the sample is attracted by the electrostatic chuck ( 105 ).
1. A charged-particle beam device including an electrostatic chuck mechanism for holding a sample and a sample chamber in which the electrostatic chuck is set, the charged-particle beam device comprising:
a charged particle beam column that irradiates a charged particle beam on the sample;
a surface potential sensor that measures potential on a side of an attraction surface for the sample of the electrostatic chuck mechanism and is disposed closer to a side of the charged particle beam column than the sample; and
a control device that performs potential measurement by the surface potential sensor in a state in which the sample is attracted by the electrostatic chuck mechanism.
2. The charged-particle beam device according to claim 1 , wherein a calibration pedestal to which a retarding voltage can be applied at same height as a wafer is set in a vacuum container.
3. The charged-particle beam device according to claim 1 , wherein the surface potential sensor and a calibration pedestal are disposed in positions to be opposed to each other in a stage position in conveying a wafer into the sample chamber.
4. The charged-particle beam device according to claim 3 , wherein the control device measures, with the surface potential sensor calibrated by the calibration pedestal, wafer surface potential on the electrostatic chuck, stores a measured value as a function of a distance from a wafer center, and corrects an acceleration voltage of charged particles at one or more measurement points.
5. The charged-particle beam device according to claim 1 , further comprising a calibration pedestal to which a retarding voltage can be applied, and wherein the surface potential sensor calibrated by the calibration pedestal is used for a failure diagnosis according to whether an amount of calibration exceeds a predetermined amount.
6. The charged-particle beam device according to claim 1 , further comprising a calibration pedestal to which a retarding voltage can be applied, and wherein the surface potential sensor measures an amount of electrostatic charge on the electrostatic chuck when charges on the electrostatic chuck are removed and the control device determines whether charge removal is correctly executed.