Projection electron beam apparatus and defect inspection system using the apparatus
A sample is evaluated at a high throughput by reducing axial chromatic aberration and increasing the transmittance of secondary electrons. Electron beams emitted from an electron gun 1 are irradiated onto a sample 7 through a primary electro-optical system, and electrons consequently emitted from the sample are detected by a detector 12 through a secondary electro-optical system. A Wien filter 8 comprising a multi-pole lens for correcting axial chromatic aberration is disposed between a magnification lens 10 in the secondary electro-optical system and a beam separator 5 for separating a primary electron beam and a secondary electron beam, for correcting axial chromatic aberration caused by an objective lens 14 which comprises an electromagnetic lens having a magnetic gap defined on a sample side.
1. An electron beam apparatus having a projection electro-optical system for inspecting a surface of a sample, comprising:
an electron gun for emitting an electron beam;
a primary electro-optical system for guiding the emitted electron beam onto a sample for irradiation;
a detector for detecting electrons; and
a secondary electro-optical system for guiding an electron beam bearing information on the surface of the sample, emitted from the sample irradiated with the electron beam, to the detector;
wherein the secondary electro-optical system includes a Wien filter having two focus points.
2. A defect inspection system for inspecting a defect on a surface of a sample, comprising:
an electron beam apparatus having a projection electro-optical system, as claimed in claim 1 ;
an image capturer for generating an image of the surface of the sample based on information on the surface of the sample included in electrons detected by the detector of the electron beam apparatus; and
a defect evaluator for testing the presence or absence of a defect on the surface of the sample by comparing the captured image with a reference image.