Testing apparatus using charged particles and device manufacturing method using the testing apparatus

• US 20090101816A1
• Filed: 03/11/2008
• Published: 04/23/2009
• Est. Priority Date: 04/22/2003
• Status: Active Grant

• Current Assignee: Ebara Corporation
• Original Assignee: Ebara Corporation
• Inventors: Kimba, Toshifumi, Murakami, Takeshi, Watanabe, Kenji, Yoshikawa, Shoji, Noji, Nobuharu, Sobukawa, Hirosi, Hatakeyama, Masahiro, Satake, Tohru, Tajima, Ryo, Suematsu, Kenichi, Karimata, Tsutomu, Tabe, Yutaka, Tohyama, Keiichi
• Granted Patent: US 7,741,601 B2
• Time in Patent Office: Days
• US Class Current: 250/310
• CPC Class Codes: G01N 23/2204 Specimen supports therefor; Sample conveying means therefore
• CPC Class Codes: G01N 23/225 using electron or ion
• CPC Class Codes: H01J 2237/202 Movement
• CPC Class Codes: H01J 2237/2441 Semiconductor detectors, e.g. diodes
• CPC Class Codes: H01J 2237/2446 Position sensitive detectors
• CPC Class Codes: H01J 2237/2801 Details
• CPC Class Codes: H01J 2237/2817 Pattern inspection
• CPC Class Codes: H01J 37/05 Electron or ion-optical arrangements for separating electrons or ions according to their energy or massparticle separator tubes H01J49/00
• CPC Class Codes: H01J 37/20 Means for supporting or positioning the objects or the material; Means for adjusting diaphragms or lenses associated with the support introducing the objects H01J37/18
• CPC Class Codes: H01J 37/28 with scanning beams H01J37/268, H01J37/292, H01J37/2955 take precedence
• CPC Class Codes: H01L 21/6833 Details of electrostatic chucks
• CPC Class Codes: H01L 2223/54466 Located in a dummy or reference die

Abstract

A system for further enhancing speed, i.e. improving throughput in a SEM-type inspection apparatus is provided. An inspection apparatus for inspecting a surface of a substrate produces a crossover from electrons emitted from an electron beam source 25•1, then forms an image under a desired magnification in the direction of a sample W to produce a crossover. When the crossover is passed, electrons as noises are removed from the crossover with an aperture, an adjustment is made so that the crossover becomes a parallel electron beam to irradiate the substrate in a desired sectional form. The electron beam is produced such that the unevenness of illuminance is 10% or less. Electrons emitted from the sample W are detected by a detector 25•11.

Claims

1. An electron beam apparatus comprising:

means for irradiating an electron bean to a sample;

means for directing electrons having information of the surface of said sample with irradiation of the electron beam to said sample to a detector; and

means for synthesizing said electrons guided to the detector as an image,

wherein the illuminance of said electron beam in an area on said sample to which said electron beam is irradiated is uniform, and wherein said electrons having the surface of said sample are mirror electrons reflected near the surface of said sample.

2. An electron beam apparatus comprising:

means for irradiating an electron beam to a sample;

means for making electrons having information of the surface of said sample with irradiation of the electron beam to said sample form the magnified image on a detector; and

means for synthesizing as an image said electrons made to form the image on the detector,

wherein the current density and/or energy of said electron beam are set to values such that said sample is not damaged by irradiation of said electron beam.

3. The electron beam apparatus according to claim 2, wherein said electrons are at least one of secondary electrons, reflection electrons and back-scattered electrons, generated from said sample.

4. The electron beam apparatus according to claim 2, wherein said electrons are mirror electrons reflected near the surface of said sample.

5. The electron bean apparatus according to claim 2, wherein said current density is set to 1 A/cm².

6. The electron beam apparatus according to claim 5, wherein said energy is set to 1 eV to 15 keV

7. The electron beam apparatus according to claim 2, wherein the amount of said electron beam irradiated to said sample is set to 1E-7 to 3E-1 C/cm².

8. The electron beam apparatus according to claim 3, wherein said means for irradiating the electron beam to the sample and said means for forming the magnified image on the detector respectively comprise an optical system having an electrostatic lens.

9. The electron beam apparatus according to claim 8, wherein the shape of the irradiation area irradiated with said electron beam is approximately symmetric with respect to two axes orthogonal to the optical axis of said electron beam.

10. The electron beam apparatus according to claim 2, further comprising means for separating said electron beam irradiated to said sample from said electrons, said separating means including means for generating an electric field and a magnetic field.

11. An electron bean apparatus comprising:

means for directing an electron beam to a sample;

means for magnifying and projecting electrons having information of the surface of said sample with irradiation of said electron beam to said sample to form a magnified image on a detector; and

means for synthesizing as an image said electrons magnified and projected to form the magnified image on the detector,

said electron beam apparatus further comprising means for changing said irradiation area to keep the current density constant in any magnification of projection.

12. The electron bean apparatus according to claim 11, wherein said electrons are at least one of secondary electrons, reflection electrons and back-scattered electrons generated from said sample.

13. The electron beam apparatus according to claim 11, wherein said electrons are mirror electrons reflected near the surface of said sample.

14. The electron beam apparatus according to claim 11, further comprising means for changing the shape of said irradiation area while keeping the shape analogous in accordance with said magnification of projection.

15. The electron beam apparatus according to claim 11, wherein the area of said irradiation area has a size approximately identical to that of an area in which said electrons are synthesized as an image, or a size including an area in which said electrons magnified and projected by said detector is synthesized to font a magnified image on said detector.

16. The electron beam apparatus according to claim 11, further comprising means for continuously changing said magnification of projection, said apparatus being operable to control the area of said irradiation area in accordance with the means, whereby approximately same signal-to-noise ratios are obtained.

17. An electron bean apparatus comprising:

means for irradiating an electron beam to a sample;

means for magnifying and projecting electrons having information of the surface of said sample with irradiation of said electron bean to said sample to form a magnified image on a detector; and

means for synthesizing as an image said electrons made to form the magnified image on the detector,

illuminance of said electron beam in said irradiation area being uniform,

said means to form the magnified image constituting an optical system comprising an electrostatic lens,

means for separating said electron beam from said electrons comprising a deflector using an electric field and a magnetic field,

the center of the magnified image formed by the projection on said detector and the center of said electrostatic lens being on a common axis, and

the optical axis of said electron beam coinciding with said common axis in a section between said deflector and said sample, said optical axis of said electron beam being approximately perpendicular to said sample, and wherein said electrons are mirror electrons reflected near the surface of said sample.

18. In an electron beam inspection method comprising the steps of:

irradiating an electron beam to a sample;

directing electrons having information of the surface of said sample with irradiation of the electron beam to said sample to a detector; and

synthesizing as an image said electrons guided to the detector,

said electron beam inspection method including the steps of;

generating said electron beam;

determining irradiation energy and a current density at which said electron beam is irradiated to said sample;

determining an area of an irradiation area in which said electron beam is irradiated to said sample;

determining a shape of the irradiation area in which said electron beam is irradiated to said sample;

keeping uniform the illuminance of said electron bean in said irradiation area;

separating said electrons and then directing the electrons to said detector; and

selecting said electrons guided to said detector,

wherein said electrons are mirror electrons reflected near the surface of said sample.