Electron beam apparatus and a device manufacturing method using the same apparatus

• US 7,385,197 B2
• Filed: 07/07/2005
• Issued: 06/10/2008
• Est. Priority Date: 07/08/2004
• Status: Expired due to Fees

• Current Assignee: Ebara Corporation
• Original Assignee: Ebara Corporation
• Inventors: Sobukawa, Hirosi, Hatakayama, Masahiro, Kaga, Toru, Murakami, Takeshi, Noji, Nobuharu, Satake, Tohru, Nakasuji, Mamoru
• Primary Examiner(s): Vanore; David
• Assistant Examiner(s): SOUW, BERNARD E
• Application Number:
  US11/175,390
• Publication Number:
  US 20060016989A1
• Time in Patent Office: 1,069 Days
• Field of Search: 250/310
• US Class Current: 250/310
• CPC Class Codes: G01N 23/2251 using incident electron beams, e.g. scanning electron microscopy [SEM]
• CPC Class Codes: H01J 2237/14 magnetic
• CPC Class Codes: H01J 2237/1508 Combined electrostatic-electromagnetic means
• CPC Class Codes: H01J 2237/1526 For X-Y scanning
• CPC Class Codes: H01J 2237/2447 Imaging plates
• CPC Class Codes: H01J 2237/24592 Inspection and quality control of devices
• CPC Class Codes: H01J 37/244 Detectors; Associated components or circuits therefor
• CPC Class Codes: H01J 37/28 with scanning beams H01J37/268, H01J37/292, H01J37/2955 take precedence

Abstract

Disclosed is an electron beam apparatus, in which a plurality of electron beams is formed from electrons emitted from an electron gun 21 and used to irradiate a sample surface via an objective lens 28, said apparatus comprising: a beam separator 27 for separating a secondary electron beams emanating from respective scanned regions on the sample from the primary electron beams; a magnifying electron lens 31 for extending a beam space between adjacent beams in the separated plurality of secondary electron beams; a fiber optical plate 32 for converting the magnified plurality of secondary electron beams to optical signals by a scintillator and for transmitting the signals; a photoelectric conversion device 35 for converting the optical signal to an electric signal; an optical zoom lens 33 for focusing the optical signal from the scintillator into an image on the photoelectric conversion device; and a rotation mechanism 36 for rotating the photoelectric conversion device 35 around the optical axis.

Claims

1. An electron beam apparatus comprising:

an electron irradiation optics for irradiating a plurality of primary electron beams onto a sample surface;

a scanning deflector for performing a scanning operation with said plurality of primary electron beams across the sample surface;

a beam separator for separating secondary electron beams emanating from respective scanned regions on the sample from said primary electron beam;

a magnifying electron lens for magnifying a distance between any two beams of the plurality of secondary electron beams that have been separated by said beam separator;

an optical output converter for converting the plurality of magnified secondary electron beams to optical signals;

a photoelectric conversion device for converting said optical signal to an electric signal;

an optical magnifying lens for magnifying said optical signal from said optical output converter into an image on said photoelectric conversion device; and

a multi-aperture plate disposed in front of said photoelectric conversion device and having a plurality of apertures formed therethrough, said aperture having an aperture area that is large in a peripheral region.

2. An electron beam apparatus comprising:

an irradiation optical system for focusing a primary electron beams onto a sample surface via an objective lens;

an image projection optical system including at least two-stage of deflectors, an magnifying lens and an aperture for detecting secondary electrons emanating from the sample;

a wobbler application circuit for applying a wobbler to an exciting or an excitation voltage of said magnifying lens subject to axial alignment;

an image formation system for forming an image separated by the wobbler in synchronization with the x- and y-directional scanning according to a signal from the electron beam transmitted through said aperture, while carrying out the x- and y-directional scanning by at least one of the deflectors in the at least two-stage of deflectors; and

a deflector controller operable to control the other one of said at least two-stage of deflectors to minimize the separation of the image for the purpose of adjusting the optical axis so that a principal ray having exited from said objective lens is directed through a central region of said magnifying lens and through said aperture.

3. An electron beam apparatus comprising:

an irradiation optical system for focusing a primary electron beam onto a sample surface via an objective lens;

an image projection optical system for focusing secondary electrons emanating from the sample into an image on a detection surface, said image projection optical system having at least two-stage of deflectors, a magnifying lens and an aperture;

an optical output converter for converting the secondary electron image formed by said image projection optical system to an optical signal;

an optical member for extracting said optical signal into an atmosphere side, in which a plane disposed in a vacuum side of said optical member defines an optical output converter and an output surface of the optical signal disposed in the atmosphere side defines a curved surface;

a wobbler application circuit for applying a wobbler to an exciting or an excitation voltage of said magnifying lens subject to axial alignment;

an image formation system for forming an image separated by the wobbler in synchronization with the x- and y-directional scanning according to a signal from the electron beam transmitted through said aperture, while carrying out the x- and y-directional scanning by at least one of the deflectors in the at least two-stage of deflectors; and

a deflector controller operable to control the other one of said at least two-stage of deflectors to minimize the separation of the image for the purpose of adjusting the optical axis so that a principal ray having exited from said objective lens is directed through a central region of said magnifying lens and through said aperture.

4. An electron beam apparatus comprising:

an irradiation optical system for focusing a primary electron beam onto a sample surface via an objective lens;

an image projection optical system for focusing secondary electrons emanating from the sample into an image on a detection surface;

an optical output converter for converting the secondary electron image formed by said image projection optical system to an optical signal;

an optical member for extracting said optical signal into an atmosphere side, in which a plane disposed in a vacuum side of said optical member defines an optical output converter and an output surface of the optical signal disposed in the atmosphere side defines a curved surface;

wherein said objective lens comprises;

a magnetic lens including an inner magnetic pole and an outer magnetic pole with a magnetic gap produced by said inner and said outer magnetic poles defined in the sample side;

a pipe made of ferrite and disposed inside said inner magnetic pole; and

a deflector disposed inside said pipe made of ferrite.

5. An objective lens for focusing an electron beam onto a sample surface, comprising:

a magnetic lens including an inner magnetic pole and an outer magnetic pole with a magnetic gap produced by said inner and said outer magnetic poles defined in the sample side;

a substantially cylindrical pipe made of ferrite and disposed inside said inner magnetic pole; and

a deflector disposed inside said pipe made of ferrite.