Apparatus and method for testing defects

• US 7,692,779 B2
• Filed: 10/06/2005
• Issued: 04/06/2010
• Est. Priority Date: 04/02/1991
• Status: Expired due to Fees

• Current Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.), Hitachi, Ltd.
• Original Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.), Hitachi, Ltd.
• Inventors: Matsunaga, Ryouji, Sakai, Keiji, Matsumoto, Shunichi, Nishiyama, Hidetoshi, Jingu, Takahiro, Ohshima, Yoshimasa, Ninomiya, Takanori, Noguchi, Minori, Watanabe, Tetsuya, Chikamatsu, Shuichi, Morishige, Yoshio, Kembo, Yukio, Nakamura, Hisato
• Primary Examiner(s): Chowdhury; Tarifur R.
• Assistant Examiner(s): Akanbi; Isiaka O
• Application Number:
  US11/244,080
• Publication Number:
  US 20060030060A1
• Time in Patent Office: 1,643 Days
• Field of Search: 3562372-2375
• US Class Current: 356/237.5
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G01N 2021/8822 Dark field detection
• CPC Class Codes: G01N 21/94 Investigating contamination, e.g. dust G01N21/85 takes precedence
• CPC Class Codes: G01N 21/95623 using a spatial filtering method per se G02B
• CPC Class Codes: G01N 21/95684 Patterns showing highly reflecting parts, e.g. metallic elements
• CPC Class Codes: G01R 31/308 using non-ionising electromagnetic radiation, e.g. optical radiation investigating or analysing materials by the use of optical means G01N21/00; image analysis G06T7/00
• CPC Class Codes: H01J 2237/022 Avoiding or removing foreign or contaminating particles, debris or deposits on sample or tube
• CPC Class Codes: H01J 2237/0225 Detecting or monitoring foreign particles
• CPC Class Codes: H01J 37/00 Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof H01J33/00, H01J40/00, H01J41/00, H01J47/00, H01J49/00 take precedence
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring
• CPC Class Codes: H01L 21/67288 Monitoring of warpage, curvature, damage, defects or the like
• CPC Class Codes: H01L 21/681 using optical controlling means
• 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

An apparatus for detecting defects on a specimen including an illumination optical unit which obliquely projects a laser onto a region which is longer in one direction than in a direction transverse to said one direction on a surface of a specimen, a table unit which mounts said specimen and which is movable, a detection optical unit which detects with an image sensor an image of light formed by light reflected from said specimen in both directions of the one direction and the direction transverse and which reflected light in both directions is formed on said image sensor while said table is moving, a signal processor which processes a signal outputted from said image sensor of said detection optical unit to extract defects of said specimen. A display unit which displays information of defects extracted by said signal processor.

Claims

1. A defect inspecting apparatus comprising:

an illumination optical unit for obliquely illuminating an object with a laser, which is converged in one direction and collimated in a direction transverse to the one direction;

a first detection optical unit including a first image sensor for detecting a first image formed by light reflected from the object by the illumination of the laser and reflected in a first direction inclined with respect to a normal direction to a surface of the object;

a second detection optical unit including a second image sensor for detecting a second image formed by light reflected from the object by the illumination of the laser and reflected in a second direction which is inclined to the normal direction to the surface of the object;

an image signal processing unit which processes both of a signal outputted from the first detection optical unit by the detection of the first image and a signal outputted from the second detection optical unit by the detection of the second image; and

an output unit which outputs information processed by the image signal processing unit;

wherein both of the first detection optical unit and the second detection optical unit includes a variable spatial filter which cuts off light reflected from patterns formed on the object.

2. A defect inspecting apparatus according to claim 1, wherein the second direction is inclined with respect to the first direction.

3. A defect inspecting apparatus according to claim 1, wherein the variable spatial filter includes a liquid crystal device.

4. A defect inspecting apparatus according to claim 1, wherein the variable spatial includes plural patterns which cut off the light reflected from patterns formed on the object, the plural patterns having pitches which are changeable.

5. A defect inspecting apparatus according to claim 1, wherein the illumination optical unit controls a polarization state of the laser.

6. A defect inspecting apparatus according to claim 5, wherein both of the first detection optical unit and the second detection optical unit includes a polarizing element.

7. A defect inspecting apparatus according to claim 1, wherein both of the first image sensor and the second image sensor is a CCD image sensor.

8. A defect inspecting apparatus according to claim 1, wherein the illumination optical unit includes a cylindrical lens.

9. A defect inspecting apparatus according to claim 1, wherein the illumination optical unit projects an ultraviolet laser.

10. A defect inspecting apparatus according to claim 1, wherein the laser is a slit-like shaped laser.

11. A defect inspecting apparatus comprising:

an illumination optical unit which obliquely projects a laser focused onto a line on a surface of an object, the laser being converged in one direction and collimated in a direction transverse to the one direction;

a first detection optical unit including a first image sensor for detecting a first image formed by light reflected from the object by the illumination of the laser and reflected in a first direction which is inclined with respect to a normal direction to a surface of the object;

a second detection optical unit including a second image sensor for detecting a second image formed by the light reflected from the object by the illumination of the laser and reflected in a second direction which is inclined to the normal direction to the surface of the object;

an image signal processing unit which processes both of a signal outputted from the direction optical unit by the detection of the first image and a signal outputted from the second detection optical unit by the detection of the second image; and

an output unit which outputs information processed by the image signal processing unit;

wherein both of the first detection optical unit and the second detection optical unit includes a variable spatial filter which cuts off light reflected from patterns formed on the object.

12. A defect inspecting apparatus according to claim 11, wherein the second direction is inclined with respect to the first direction.

13. A defect inspecting apparatus according to claim 11, wherein the variable spatial filter includes a liquid crystal device.

14. A defect inspecting apparatus according to claim 11, wherein the variable spatial filter includes plural patterns which cut off the light reflected from patterns formed on the object, the plural patterns having pitches which are changeable.

15. A defect inspecting apparatus according to claim 11, wherein the illumination optical unit controls a polarization state of the laser.

16. A defect inspecting apparatus according to claim 15, wherein both of the first detection optical unit and the second detection optical unit includes a polarizing element.

17. A defect inspecting apparatus according to claim 11, wherein both of the first image sensor and the second image sensor is a CCD image sensor.

18. A defect inspecting apparatus according to claim 11, wherein the illumination optical unit includes a cylindrical lens.

19. A defect inspecting apparatus according to claim 11, wherein the illumination optical unit projects an ultraviolet laser.

20. A defect inspecting apparatus according to claim 11, wherein the laser is a slit-like shaped laser.