Charged particle beam apparatus

• US 8,586,920 B2
• Filed: 10/28/2009
• Issued: 11/19/2013
• Est. Priority Date: 11/05/2008
• Status: Active Grant

• Current Assignee: Hitachi High-Tech Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.)
• Inventors: Tsuno, Natsuki, Makino, Hiroshi
• Primary Examiner(s): NGUYEN, KIET TUAN
• Application Number:
  US13/126,198
• Publication Number:
  US 20110204228A1
• Time in Patent Office: 1,483 Days
• Field of Search: 250/310, 356/237.4
• US Class Current: 250/310
• CPC Class Codes: H01J 2237/24507 Intensity, dose or other characteristics of particle beams or electromagnetic radiation
• CPC Class Codes: H01J 2237/24592 Inspection and quality control of devices
• CPC Class Codes: H01J 2237/2482 Optical means
• CPC Class Codes: H01J 2237/2814 Measurement of surface topography
• CPC Class Codes: H01J 2237/2817 Pattern inspection
• CPC Class Codes: H01J 37/224 Luminescent screens or photographic plates for imaging photosensitive materials for photographic purposes G03C; Apparatus specially adapted therefor, e.g. cameras, TV-cameras, photographic equipment, exposure control; Optical subsystems specially adapted therefor, e.g. microscopes for observing image on luminescent screen
• CPC Class Codes: H01J 37/28 with scanning beams H01J37/268, H01J37/292, H01J37/2955 take precedence
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

It has been difficult to obtain pattern contrast required for inspecting a specific layer of a circuit pattern in a charged particle beam apparatus which inspects, by using a charged particle beam, the position and type of a defect on a wafer having a circuit pattern which is in semiconductor manufacturing process. At the time of inspecting the position and type of a defect on a wafer having a circuit pattern which is in semiconductor manufacturing process by using a charged particle beam emitted from a charged particle source (11), the wafer arranged on a holder (20) is irradiated with light in wavelength ranges different from each other from a light irradiation system (9), and at the same time, the wafer is irradiated with a charged particle beam. Thus, contrast of an image is improved and inspection is performed with high sensitivity.

Claims

1. A charged particle beam apparatus comprising:

a charged particle gun;

a specimen holder with a specimen placed thereon;

a charged particle optical system that irradiates the specimen placed on the specimen holder with charged particle beams radiated from the charged particle gun;

a detector that detects secondary electrons generated by irradiation of the specimen with the charged particle beams;

an image processing unit that executes image processing of signals of the secondary electrons detected by the detector; and

a photoirradiation system capable of simultaneously irradiating an identical region of the specimen placed on the specimen holder with light of a first wavelength band, and light of a second wavelength band, differing in wavelength band from each other,

wherein the photoirradiation system comprises a beam splitter for integrating respective optical paths of the light of the first wavelength band, and the light of the second wavelength band.

2. The charged particle beam apparatus according to claim 1, wherein a combination of the first wavelength band and the second wavelength band can be changed.

3. The charged particle beam apparatus according to claim 1, wherein the light of the first wavelength band, and the light of the second wavelength band are lights having an output not less than 1/e of the peak output, respectively, not overlapping each other.

4. The charged particle beam apparatus according to claim 3, wherein the light of the first wavelength band, and the light of the second wavelength band are lights of wavelength bands in a range of 133 to 180 nm, and in a range of 200 to 266 nm, respectively.

5. The charged particle beam apparatus according to claim 1, wherein the photoirradiation system comprises a light source, a first beam splitter for splitting an optical path of light emitted from the light source, filters provided in respective optical paths of the light, split by the first beam splitter, for changing a wavelength band, and a second beam splitter for integrating the respective optical paths of the light into one optical path, the light of the first wavelength band, and the light of the second wavelength band making up light irradiated from the second beam splitter.

6. The charged particle beam apparatus according to claim 5, wherein filters for adjusting output energy of light, and shutters for shielding light, respectively, are provided in the respective optical paths of the light between the light of the first wavelength band, and the light of the second wavelength band.

7. The charged particle beam apparatus according to claim 1, further comprising an absorptivity meter for measuring light absorptivity at a predetermined layer of the specimen with the use of light irradiated from the photoirradiation system.

8. The charged particle beam apparatus according to claim 1, further comprising a display device for inputting information on constituent layers of the specimen, and a photoirradiation controller for controlling a combination of the first wavelength band and the second wavelength band, wherein the photoirradiation controller controls the photoirradiation system such that the first wavelength band is desirably combined with the second wavelength band on the basis of the information on the constituent layers, inputted by the display device.

9. The charged particle beam apparatus according to claim 8, further comprising a database for accumulating information on material of a predetermined layer, and absorptivity of a wavelength of light, wherein control of the photoirradiation system is executed on the basis of the information accumulated in the database.

10. The charged particle beam apparatus according to claim 1, wherein either the light of the first wavelength band, or the light of the second wavelength band is light causing a predetermined layer of the specimen to be negatively charged.

11. A charged particle beam apparatus comprising:

a charged particle gun;

a specimen holder with a specimen placed thereon;

a charged particle optical system that irradiates the specimen placed on the specimen holder with charged particle beams radiated from the charged particle gun;

a detector that detects secondary electrons generated by irradiation of the specimen with the charged particle beams;

an image processing unit that executes image processing of signals of the secondary electrons detected by the detector; and

a photoirradiation system that irradiates the specimen placed on the specimen holder with light,

wherein the photoirradiation system includes a beam splitter for integrating respective optical paths of light of a first wavelength band, and light of a second wavelength band, differing in wavelength band from each other.

12. The charged particle beam apparatus according to claim 11, wherein the photoirradiation system comprises a light source, a second beam splitter differing from the beam splitter, for splitting an optical path of light emitted from the light source, filters provided in respective optical paths of the light, split by the second beam splitter, for changing respective wavelength bands, the photoirradiation system integrating the light of the first wavelength band, and the light of the second wavelength band before irradiating the specimen with light.

13. The charged particle beam apparatus according to claim 12, wherein a filter for adjusting output energy of light, and a shutter for shielding light are provided in respective optical paths of the light of the first wavelength band, and the light of the second wavelength band between the beam splitter and the second beam splitter.

14. The charged particle beam apparatus according to claim 11, wherein the light of the first wavelength band, and the light of the second wavelength band are lights having an output not less than 1/e of the peak output, respectively, not overlapping each other.

15. The charged particle beam apparatus according to claim 11, wherein either the light of the first wavelength band, and the light of the second wavelength band is light causing a predetermined layer of the specimen to be negatively charged.

16. A charged particle beam apparatus for inspection of a specimen having a structure comprised of third, second, and first layers that are stacked on top of each other in orderly sequence, said charged particle beam apparatus including:

a charged particle gun;

a specimen holder with the specimen placed thereon;

a photoirradiation system that simultaneously irradiates light of a first wavelength band to be absorbed by the first layer, and light of a second wavelength band transmitting through the first layer, and the second layer to be absorbed by the third layer;

a charged particle optical system that causes the first layer positively charged due to irradiation with the light of the first wavelength band, and the second layer negatively charged by the agency of photo electrons, the photo electrons being generated in the third layer due to irradiation thereof with the light of the second wavelength band, to be irradiated with charged particle beams radiated from the charged particle gun;

a detector that detects secondary electrons generated by irradiation of the first layer and the second layer with the charged particle beams; and

an image processing unit that executes image processing of signals of the secondary electrons detected by the detector.

17. The charged particle beam apparatus according to claim 16, further comprising a display device for inputting respective constituent materials of the first to the third layers, and a photoirradiation controller for controlling a combination of the first wavelength band and the second wavelength band, wherein the photoirradiation controller controls the photoirradiation system such that the first wavelength band is desirably combined with the second wavelength band on the basis of the information on the constituent materials, inputted by the display device.

18. The charged particle beam apparatus according to claim 16, wherein a defect inspection is performed according to an image obtained by image processing executed by the image processing unit.

19. The charged particle beam apparatus according to claim 16, wherein the light of the first wavelength band, and the light of the second wavelength band are lights having an output not less than 1/e of the peak output, respectively, not overlapping each other.