Electron beam apparatus
First Claim
1. An electron beam apparatus having a mounting stage for supporting a specimen, an electron source for generating an electron beam to be incident on said specimen, an objective magnetic lens for focussing said electron beam on said specimen, a light source for generating a light beam, and a light detector for detecting said light beam, an optical path for said light beam being defined from said light source to said light detector via said specimen;
- wherein said objective magnetic lens comprises first and second magnetic poles for generating a magnetic field of said objective magnetic lens therebetween, said first and second magnetic poles being respectively arranged on opposite sides of said optical path, said optical path being at least partially delimited between the complete extent of said first and second magnetic poles.
1 Assignment
0 Petitions
Accused Products
Abstract
An electron beam apparatus focusses an electron beam onto a specimen by means of an objective magnetic lens. In order to detect changes in the height of the specimen, a laser light beam from a laser source is incident on the specimen and the reflected laser beam is detected by a light detector. Any change in the height of the specimen changes the path of the laser beam to the detector. Therefore, by monitoring the detector, the focussing of the electron beam on the specimen can be controlled by varying the current to an excitation coil of the objective magnetic lens or by moving the specimen via a mounting stage. At least one of the pole pieces of the objective lens is on the opposite side of the path of the laser beam to the source of the electron beam, so that the objective magnetic lens may be close to the specimen, permitting a short focal length. Thus, the laser beam may pass between the pole pieces. An optical microscope may also be provided to permit the specimen to be viewed. The viewing path of the optical microscope extends through an opening in one or both of the pole pieces of the objective magnetic lens.
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Citations
11 Claims
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1. An electron beam apparatus having a mounting stage for supporting a specimen, an electron source for generating an electron beam to be incident on said specimen, an objective magnetic lens for focussing said electron beam on said specimen, a light source for generating a light beam, and a light detector for detecting said light beam, an optical path for said light beam being defined from said light source to said light detector via said specimen;
- wherein said objective magnetic lens comprises first and second magnetic poles for generating a magnetic field of said objective magnetic lens therebetween, said first and second magnetic poles being respectively arranged on opposite sides of said optical path, said optical path being at least partially delimited between the complete extent of said first and second magnetic poles.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An electron beam apparatus having a mounting stage for supporting a specimen, an electron source for generating an electron beam to be incident on a first side of said specimen, said specimen having a second side opposite said first side, an objective magnetic lens for focussing said electron beam on said specimen, a light source for generating a light beam, and a light detector for detecting said light beam, an optical path for said light beam being defined from said light source to said light detector via said specimen, said optical path having a first side facing toward said electron source and a second side opposite said first side and facing away from said electron source;
- wherein said objective magnetic lens comprises first and second magnetic poles for generating a magnetic field of said objective magnetic lens therebetween, said first and second magnetic poles being arranged on the second side of said optical path facing away from said electron source, and at least one of said first and second magnetic poles being arranged on said second side of said specimen.
- View Dependent Claims (11)
Specification