Apparatus and method for testing defects

• US 7,443,496 B2
• Filed: 03/05/2007
• Issued: 10/28/2008
• 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: Sakai, Keiji, Matsumoto, Shunichi, Nishiyama, Hidetoshi, Jingu, Takahiro, Ohshima, Yoshimasa, Ninomiya, Takanori, Noguchi, Minori, Watanabe, Tetsuya, Chikamatsu, Shuichi, Morishige, Yoshio, Matsunaga, Ryouji, Nakamura, Hisato, Kembo, Yukio
• Primary Examiner(s): Chowdhury; Tarifur R.
• Assistant Examiner(s): Akanbi; Isiaka O
• Application Number:
  US11/681,996
• Publication Number:
  US 20070146697A1
• Time in Patent Office: 603 Days
• Field of Search: 3562372-2375
• US Class Current: 356/237.2
• 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

A defect inspection apparatus includes an illumination optical unit for obliquely illuminating an object with a slit-like shaped laser, a first detection optical unit for detecting a first image formed by light reflected from the object by the illumination of the slit-like shaped laser and reflected in a first direction substantially normal to a surface of the object, a second detection optical unit for detecting a second image formed by light reflected from the object by the illumination of the slit-like shaped laser and reflected in a second direction inclined to the normal direction to the surface of the object, an image signal processing unit which processes a signal outputted from the first detection optical unit and a signal outputted from the second detection optical unit, and an output unit which outputs information processed by the image signal processing unit.

Claims

1. A defect inspection apparatus comprising:

an illumination optical unit for obliquely illuminating an object with a slit-like shaped laser, the slit-like shaped 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 slit-like shaped laser and reflected in a first direction substantially normal 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 slit-like shaped laser and reflected in a second direction 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 the first detection optical unit includes a spatial filter which cuts off light reflected from patterns formed on the object; and

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

2. The defect inspecting apparatus according to claim 1, further comprising a third detection optical unit including a third image sensor for detecting a third image formed by light reflected from the object by the illumination of the slit-like shaped laser and reflected in a third direction inclined to the normal direction to the surface of the object.

3. The defect inspecting apparatus according to claim 1, wherein the illumination optical unit controls a polarization state of the slit-like shaped laser.

4. The defect inspecting apparatus according to claim 1, wherein the first detection optical unit includes a polarization device which controls a polarization state of the reflected light.

5. The defect inspecting apparatus according to claim 1, wherein the variable spatial filter of the second detection optical unit includes plural patterns which cut off the light reflected from patterns formed on the object, the plural patterns having pitches which are changeable.

6. The defect inspecting apparatus according to claim 1, wherein the illumination optical unit obliquely illuminates the object with a slit-like shaped ultraviolet laser.

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

8. A defect inspecting apparatus comprising:

an illumination optical unit which obliquely projects a slit-like shaped laser focused onto a line on a surface of an object, the slit-like shaped 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 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 inclined to the first 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 the first detection optical unit includes a spatial filter which cuts off light from patterns formed on the object; and

wherein the second detecting optical unit includes a variable spatial filter which cuts off light reflected from patterns formed on the object.

9. The defect inspecting apparatus according to claim 8, wherein the first direction is a substantially normal direction to the surface is inclined to the surface of the object with respect to the normal direction.

10. The defect inspecting apparatus according to claim 8, further comprising a third detection optical unit including a third image sensor for detecting a third image formed by light reflected from the object by the illumination of the laser and reflected to a third direction which is more inclined than the second direction to the surface of the object.

11. The defect inspecting apparatus according to claim 8, wherein the illumination optical unit controls a polarization state of the laser.

12. The defect inspecting apparatus according to claim 8, wherein the first detection optical unit includes polarization device which controls a polarization state of the reflected light.

13. The defect inspecting apparatus according to claim 8, wherein the variable spatial filter of the second detection optical unit includes plural patterns which cut off the light reflected from patterns formed on the object, the plural patterns having pitches which are changeable.

14. The defect inspecting apparatus according to claim 8, wherein the illumination optical unit obliquely illuminates the object with a slit-like shaped ultraviolet laser.

15. The defect inspecting apparatus according to claim 8, wherein the variable spatial filter includes a liquid crystal device.