Method of evaluating primary optical system of electron beam observation device, evaluation device used therefor, and method of manufacturing same
Provided is a method of evaluating a deviation of a trajectory of a primary electron beam in a primary optical system in an electron beam observation device including the primary optical system that irradiates a sample with the primary electron beam including a plurality of primary electrons and a secondary optical system that detects, by a detector, a secondary electron beam including a plurality of secondary electrons emitted from the sample irradiated with the primary electron beam.
1 . A method of evaluating a deviation of a trajectory of a primary electron beam in a primary optical system in an electron beam observation device including the primary optical system that irradiates a sample with the primary electron beam including a plurality of primary electrons and a secondary optical system that detects, by a detector, a secondary electron beam including a plurality of secondary electrons emitted from the sample irradiated with the primary electron beam, the method comprising the steps of:
irradiating an irradiation target with a primary electron beam generated by a multiple beam generation mechanism provided with a plurality of openings, and acquiring a first image formed by a secondary electron beam from the irradiation target, the first image including a plurality of first patterns each of which corresponding to each of the openings provided in the multiple beam generation mechanism;
calculating a first deviation amount between a position of each of the first patterns in the first image and a first target position of the first pattern;
irradiating with light a plurality of photoelectric converters each of which corresponding to each of the plurality of openings provided in the multiple beam generation mechanism and installed on a stage of the electron beam observation device, and acquiring a second image formed by an electron beam from the photoelectric converters, the second image including a plurality of second patterns each of which corresponding to each of the photoelectric converters;
calculating a second deviation amount between a position of each of the second patterns in the second image and a second target position of the second pattern; and
obtaining a deviation of a trajectory of the primary electron beam in the primary optical system based on the first deviation amount and the second deviation amount.
2 . The evaluation method according to claim 1 , wherein
a position of each of the first patterns in the first image deviates from the first target position depending on a deviation of trajectory of the primary electron beam in the primary optical system and a deviation of a trajectory of the secondary electron beam in the secondary optical system, and
a position of each of the second patterns in the second image deviates from the second target position depending on a deviation of a trajectory of the secondary electron beam in the secondary optical system, but does not depend on a deviation of a trajectory of the primary electron beam in the primary optical system.
3 . The evaluation method according to claim 1 , wherein the irradiation target is a stage of the electron beam observation device.
4 . The evaluation method according to claim 1 , wherein
the plurality of photoelectric converters are provided on a substrate, and
the irradiation target is a part of the substrate where the photoelectric converters are not provided.
5 . A method of evaluating a deviation of a trajectory of a primary electron beam in a primary optical system in an electron beam observation device including the primary optical system that irradiates a sample with the primary electron beam including a plurality of primary electrons and a secondary optical system that detects, by a detector, a secondary electron beam including a plurality of secondary electrons emitted from the sample irradiated with the primary electron beam, the method comprising the steps of:
irradiating an irradiation target with a primary electron beam from a plurality of electron sources, and acquiring a first image formed by a secondary electron beam from the irradiation target, the first image including a plurality of first patterns each of which corresponding to each of arrangements of the plurality of electron sources;
calculating a first deviation amount between a position of each of the first patterns in the first image and a first target position of the first pattern;
irradiating with light a plurality of photoelectric converters installed on a stage of the electron beam observation device and each corresponding to the arrangement of the plurality of electron sources, and acquiring a second image formed by an electron beam from the photoelectric converters, the second image including a plurality of second patterns each of which corresponding to each of the photoelectric converters;
calculating a second deviation amount between a position of each of the second patterns in the second image and a second target position of the second pattern; and
obtaining a deviation of a trajectory of the primary electron beam in the primary optical system based on the first deviation amount and the second deviation amount.
6 . The evaluation method according to claim 5 , wherein
a position of each of the first patterns in the first image deviates from the first target position depending on a deviation of a trajectory of the primary electron beam in the primary optical system and a deviation of a trajectory of the secondary electron beam in the secondary optical system, and
a position of each of the second patterns in the second image deviates from the second target position depending on a deviation of a trajectory of the secondary electron beam in the secondary optical system, but does not depend on a deviation of a trajectory of the primary electron beam in the primary optical system.
7 . The evaluation method according to claim 5 , wherein the irradiation target is a stage of the electron beam observation device.
8 . The evaluation method according to claim 5 , wherein
the plurality of photoelectric converters are provided on a substrate, and
the irradiation target is a part of the substrate where the photoelectric converters are not provided.