Defect inspection apparatus performing defect inspection by image analysis

• US 20080285840A1
• Filed: 06/24/2008
• Published: 11/20/2008
• Est. Priority Date: 12/26/2005
• Status: Abandoned Application

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Kawai, Akitoshi
• Application Number:
  US12/213,748
• Publication Number:
  US 20080285840A1
• Time in Patent Office: Days
• US Class Current: 382/141
• CPC Class Codes: G01N 21/8851 Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges G01N21/8806 and G01N21/93 - G01N21/95692 take precedence; optical measurement of dimensions G01B11/00; optical scanning G02B26/10; image transformation G06T3/00; computerised image enhancement G06T5/00; image processing per se for flaw detection G06T7/0002
• CPC Class Codes: G01N 21/956 Inspecting patterns on the surface of objects contactless testing of electronic circuits G01R31/308; testing currency G07D; manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/001 using an image reference approach

Abstract

A defect inspection apparatus obtains a color image signal of an inspection target. Based on a plurality of signal components forming this color image signal, a plurality of analysis images are obtained. Defect detection of an inspection target is implemented for each of the a plurality of analysis images. A differential is detected for a defect nomination detected for each of the analysis images, and thereby whether a plurality of defects exist or not in successive defect positions of the inspection target is determined.

Claims

1. A defect inspection apparatus, comprising:

an illumination unit illuminating an inspection target;

an image capturing unit obtaining a color image signal of said inspection target; and

a defect detection unit detecting a defect of said inspection target based on said color image signal obtained by said image capturing unit, wherein said defect detection unit comprises;

a component extracting unit obtaining a plurality of analysis images based on a plurality of signal components forming said color image signal;

a detection unit performing defect detection of said inspection target for each of said a plurality of analysis images, and detecting a defect nomination for each of said analysis images; and

a determination unit determining sameness of said defect nominations among said a plurality of analysis images to thereby determine whether a plurality of defects exist or not in a defect position of said inspection target.

2. The defect inspection apparatus according to claim 1, wherein said component extracting unit obtains at least two of said analysis images with at least two of said signal components being taken as pixel values, said signal components being selected from a group including three signal components forming said color image signal and three signal components of hue, saturation, and intensity obtained from said signal components.

3. The defect inspection apparatus according to claim 1, wherein:

said detection unit obtains a barycentric position, a vertical length, and a horizontal length of said defect nomination for each of said analysis images;

said determination unit determines that one defect exists in the defect position of said inspection target when all of said barycentric position, said vertical length, and said horizontal length for said defect nomination for each of said analysis images are evaluated to be equal; and

said determination unit determines that a plurality of defects exist in the defect position of said inspection target when any one of said barycentric position, said vertical length, and said horizontal length is evaluated to be different.

4. The defect inspection apparatus according to claim 1, wherein said detection unit detects said defect nomination based on a differential between an analysis image of a predetermined reference image and an analysis image of said inspection target.

5. The defect inspection apparatus according to claim 4, wherein said detection unit performs level correction on the analysis image of said inspection target in an entirety thereof so that a differential between entire images of the analysis image of said reference image and the analysis image of said inspection target becomes small.

6. The defect inspection apparatus according to claim 4, wherein said detection unit has threshold values set in advance respectively for said a plurality of analysis images, and detects said defect nomination by determining with said threshold values a differential between the analysis image of the reference image and the analysis image of said inspection target.

8. The defect inspection apparatus according to claim 1, further comprising:

a microscope optical system forming an enlarged image of said inspection target; and

an imaging unit imaging said enlarged image and generating a color image signal, wherein

said image capturing unit of said defect inspection apparatus obtains said color image signal generated by said imaging unit.

7. A defect inspection apparatus, comprising:

an illumination unit illuminating an inspection target having a film on a surface;

an image capturing unit obtaining a color image signal of said inspection target; and

a defect detection unit detecting a defect of said inspection target based on said color image signal obtained by said image capturing unit, wherein said defect detection unit comprises;

a component extracting unit obtaining a color information image having a pixel value corresponding to said color information based on at least one of saturation and hue of said color image signal; and

a detection unit performing defect detection of said inspection target based on said color information image, and detecting a defect nomination on thickness of said film.