Localized static charge distribution precision measurement method and device
View Patent ↗A charged particle beam device including a function for measuring localized static charges on a sample. A primary charged particle beam scans a sample positioned in a mirror state to acquire an image. The acquired image may be an image of the sample or may be an image of a structural component in the charged particle optical system. The acquired image is compared with a standard sample image and the localized static charge is measured.
1. A charged particle beam device including:
an electron optical system to irradiate a sample with a primary charged particle beam and detect and output secondary charged particles as a signal output, and
a controller that regulates a voltage applied to the applicable electron optical system and the sample,
wherein the controller comprises a computer readable medium containing instructions that, when executed, cause the charged particle beam device to form a first image of a non-charged sample as a reference image in a state where a voltage applied to the sample that is higher than an accelerated energy of the primary charged particle beam, form a second image of a charged sample as an object of inspection in a state where the voltage applied to the sample is higher than the accelerated energy of the primary charged particle beam, and calculate a static charge of a surface of the charged sample based on a differential between the first and the second images, and
wherein the controller controls the electron optical system based on the static charge of the surface of the charged sample.
2. A charged particle beam device according to claim 1 , wherein the electron optical system contains an astigmatism compensator, and wherein the electron optical system controls the applicable astigmatism compensator based on the differential between the first and the second images.
3. A charged particle beam device according to claim 1 , wherein the electron optical system includes an adjusting unit that adjusts an optical axis of the primary charged particle beam, and wherein the electron optical system controls the applicable optical axis adjusting unit based on the differential between the first and the second images.
4. A charged particle beam device according to claim 1 , wherein the electron optical system includes an objective lens, and wherein the electron optical system controls the applicable objective lens based on the differential between the first and the second images.
5. A charged particle beam device according to claim 1 , further comprising: a second charged particle beam irradiating unit that irradiates a charged particle beam for controlling the static charge at a charged particle beam irradiation position,
wherein the electron optical system contains a static charge control electrode, and
wherein the electron optical system controls the second charged particle beam irradiation unit and the voltage applied to the static charge control electrode based on the differential between the first and the second images.
6. A charged particle beam device according to claim 1 , further comprising: an astigmatism compensator, an adjusting unit that adjusts an optical axis of the primary charged particle beam, an objective lens, a second charged particle beam irradiating unit that irradiates a charged particle beam for controlling the static charge at a charged particle beam irradiation position, and an information processing device,
wherein the information processing device stores a data table for storing control parameter values for the astigmatism compensator, the adjusting unit, the objective lens, and the second charged particle beam irradiating unit in association with the differential between the first and the second images.
7. A charged particle beam device according to claim 1 , wherein the controller forms projected images of the sample as the first and second images.
8. A charged particle beam device according to claim 5 , wherein the controller generates data that controls parameter values for the static charge control electrode and the second charged particle beam irradiating unit that are linked with position on the sample surface, and wherein the controller controls the sample surface voltage at the primary charged particle beam irradiation position by utilizing the data.