Electron beam apparatus and method of manufacturing semiconductor device using the apparatus

An electron beam apparatus for evaluating a sample surface, comprising:

• an electron gun for generating a primary electron beam;
• a primary electro-optical system for irradiating the sample by the primary electron beam generated from the electron gun;
• a scanning deflector for scanning the primary electron beam;
• a secondary electro-optical system for directing a secondary electron beam emitted from the sample surface by irradiating the primary electron beam, wherein the primary electro-optical system and the secondary electro-optical system have a common objective lens for decelerating the primary electron beam irradiating the sample and accelerating the secondary electron beam emitted from the sample surface;
• and
• a beam separator for deflecting the secondary electron beam passing through the common objective lens from the primary electro-optical system to the secondary electro-optical system, wherein the primary electro-optical system further comprises at least two stage of lenses between the electron gun and the objective lens, and an electron-beam emitted from the electron gun is enlarged by these lenses to focus a source image on an incident pupil of a final lens.

An electron beam apparatus for evaluating a sample surface, comprising:

• an electron gun for generating a primary electron beam;
• a primary electro-optical system for irradiating the sample by the primary electron beam generated from the electron gun;
• a scanning deflector for scanning the primary electron beam;
• a secondary electro-optical system for directing a secondary electron beam emitted from the sample surface by irradiating the primary electron beam, wherein the primary electro-optical system and the secondary electro-optical system have a common objective lens for decelerating the primary electron beam irradiating the sample and accelerating a secondary electron beam emitted from the sample surface;
• and
• a secondary electron beam separator for deflecting the secondary electron beam passing through the common objective lens from the primary electro-optical system to the secondary electro-optical system;
• wherein the electron beam apparatus is configured to maximize an S/N ratio of the apparatus, by maximizing (S/N)2 which is represented by an equation including MTF and a beam current value as parameters.

A method of evaluating a sample surface using an electron beam comprising:

• arranging electrons emitted from an electron gun into a plurality of primary electron beams;
• scanning the sample with the plurality of primary electron beams;
• detecting secondary electron beams emanated from the sample;
• transducing the secondary electron beams to a plurality of signals;
• amplifying the signals by a plurality of amplifiers, respectively, wherein the amplifiers are provided at a stage behind the plurality of detectors;
• and
• adjusting gains or offsets of the amplifiers and correcting the signals for non-uniformity.

A method of evaluating a sample surface comprising:

• arranging electrons emitted from an electron gun into a primary electron beam;
• irradiating the primary electron beam to the sample by scanning the primary electron beam;
• accelerating a secondary electron beam emitted from the sample irradiated with the primary electron beam;
• deflecting the secondary electron beam from a primary electro-optical system to a secondary electro-optical system;
• leading the secondary electron beam to a detector;
• detecting the secondary electron beam from the secondary electro-optical system;
• and
• maximizing a S/N ratio by maximizing (S/N)2 which is represented by an equation including MTF and a beam current value as parameters.