Scanning electron microscope
AssigneeHitachi, Ltd.
InventorsHideo Todokoro, Makoto Ezumi
Life of this patent
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Abstract
A scanning microscope is provided for producing a scan image at high spatial resolution and in a low acceleration voltage area. An acceleration tube is located in an electron beam path of an objective lens for applying a post-acceleration voltage of the primary electron beam. The application of an overlapping voltage onto a sample allows a retarding electric field against the primary electron beam to be formed between the acceleration tube and the sample. The secondary electrons generated from the sample and the secondary signals such as reflected electrons are extracted into the acceleration tube through the effect of an electric field (retarding electric field) immediately before the sample. The signals are detected by secondary signal detectors located upwardly than the acceleration tube.
Claims29
A scanning microscope for producing a two-dimensional scan image of a sample and having an electron source, scanning deflectors for scanning a primary electron beam fired from said electron source on said sample, an objective lens for converging said primary electron beam, and secondary signal detectors for detecting a secondary signal reflected from said sample, comprising:
- means for applying a post-acceleration voltage of said primary electron beam to an acceleration tube located in an electron beam path of said objective lens;
- means for applying a negative potential to said sample;
- and
- wherein a retarding electric field against said primary electron beam is created between said acceleration tube and said sample and said secondary signal detectors are located closer to said electron source than is said acceleration tube.
A scanning microscope for producing a two-dimensional scan image of a sample comprising:
- a. an electron source emitting a primary electron beam along an electron beam path;
- b. scanning deflectors for scanning said primary electron beam on said sample;
- c. an objective lens, through which said electron beam path extends, for converging said primary electron beam;
- d. a secondary signal detector for detecting secondary electrons generated from said sample;
- e. an acceleration tube located in said electron beam path extending through said objective lens;
- f. a first voltage source applying a post-acceleration voltage for said primary electron beam to said acceleration tube;
- and
- g. a second voltage source applying a negative potential to said sample to result in a retarding electric field acting against said primary electron beam being formed between said acceleration tube and said sample.
Dependencies are inferred from the claim text.