Electrostatic lens systems for secondary-electron mapping-projection apparatus, and mapping-projection apparatus and methods comprising same
AssigneeNikon Corporation
InventorsToru Takagi, Hiroshi Nishimura
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Abstract
Electron-optical systems are disclosed that are especially useful in mapping-projection electron microscopy and related uses. The systems achieve high magnification with excellent control of aberrations, and low magnification at wide optical fields with excellent control of aberrations.
Claims8
In a secondary-electron mapping-projection apparatus, an electrostatic projection-lens system comprising a front-power group and a rear-power group each having a middle electrode in common, the middle electrode and at least one electrode of the front-power group forming a front power, and the middle electrode and at least one electrode of the rear-power group forming a rear power, each of the front and rear powers being independently variable.
In a method for performing secondary-electron mapping-projection microscopy, a method for producing an image of a specimen surface at a pre-determined magnification, the method comprising:
- providing an electrostatic projection-lens system comprising a front-power group and a rear-power group each having a middle electrode in common, the middle electrode and at least one electrode of the front-power group forming a front power, and the middle electrode and at least one electrode of the rear-power group forming a rear power, each of the front and rear powers being independently variable;
- irradiating a region of the specimen surface with a charged particle beam so as to cause the specimen surface to emit secondary electrons;
- routing the secondary electrons into an end of the projection-lens system;
- and
- adjusting at least one of the front power and rear power to obtain an electron-image of the irradiated region of the specimen surface at a desired magnification.
Dependencies are inferred from the claim text.