Defect inspection method and apparatus

A method of inspecting a specimen, comprising:

• illuminating a specimen, on which plural patterns are formed, with light emitted from a light source;
• capturing a first image of a first area of the specimen in which patterns are formed;
• capturing a second image of a second area of the specimen in which patterns which are essentially the same with the patterns formed in the first area are formed;
• creating data relating to pixels of the first image and corresponding pixels of the second image;
• determining a threshold for detecting defects by using the data relating to pixels of the first image and corresponding pixels of the second image created at the step of creating;
• and
• detecting defects on the specimen by processing said first image and the second image by using said threshold.

An apparatus for inspecting a specimen, comprising:

• a light source which emits a light;
• an illuminator which illuminates a specimen, on which plural patterns are formed, with light emitted from the light sources;
• an image capturing unit which captures a first image of a first area of the specimen in which patterns are formed and a second image of a second area of the specimen in which patterns, which are essentially the same with the patterns formed in the first, area are formed;
• a pixel data creating unit which creates pixel data of the first image and corresponding pixel data of the second image;
• a threshold determining unit which determines a threshold for detecting defects by using the pixel data of the first image and corresponding pixel data of the second image created by the pixel data creating unit;
• and
• defect detecting unit which detects defects on the specimen by processing said first image and the second image by using said threshold.

A method of inspecting a specimen, comprising:

• illuminating a specimen, on which plural patterns are formed, with light emitted from a light source;
• capturing a first bright field image of a first area of the specimen in which patterns are formed;
• capturing a second bright field image of a second area of the specimen, in which patterns which are essentially the same with the patterns formed in the first area, are formed;
• aligning the first bright field image and the second bright field image with an accuracy of less than one pixel unit;
• creating data relating to pixels of the first image and corresponding pixels of the second image which are aligned with the accuracy of less than one pixel to match a brightness between the first bright field image and the second bright field image determining a threshold for detecting defects by using the data relating to pixels of the first image and corresponding pixels of the second image created at the step of creating;
• and
• detecting defects on the specimen by processing said first image and the second image by using said threshold.