Defect inspection method and apparatus therefor

A pattern inspection method, comprising the steps of:

• detecting an image of a first pattern formed on a sample;
• detecting an image of a second pattern formed on the sample;
• adjusting a brightness level of the first pattern image and the second pattern image;
• dividing said image of said first pattern and said image of said second pattern into small areas and locally adjusting a gray level of at least one of said small divided area of said first pattern image and said divided small area of said second pattern image corresponding to said first pattern image to be substantially the same with each other;
• detecting a defect of the sample by using said first pattern image and said second pattern image in which at least one of said first pattern image and said second pattern image is adjusted in at least one of gray level and brightness level;
• and
• outputting a result of the detection to an external storage or processor by communication means.

A pattern inspection system, comprising:

• a pattern image detection means for detecting an image of a first and second patterns formed on a sample;
• dividing means for dividing said images of said first and second patterns into small areas;
• a local gray level converting means for locally converting a gray level of at least one of said divided small area of said first pattern image and said divided small area of said second pattern image corresponding to said first pattern image to be substantially the same with each other;
• a brightness level adjusting means for adjusting a brightness level of at least one of said first pattern image and said second pattern image;
• a defect detecting means for detecting a defect of the sample by using said first pattern image and said second pattern image, wherein at least one of said first pattern image and second pattern image is adjusted in at least one of gray level and brightness level;
• and
• outputting means for outputting a result of the detection to an external storage or processor by communication means.

A pattern inspection system, comprising:

• an imaging unit which detects an image of a first pattern and a second pattern each formed on a sample;
• a brightness level adjuster which adjusts a brightness level of said first pattern image and said second pattern image detected by said imaging unit;
• a divider which divides said image of said first pattern and said second pattern into small areas;
• a local gray level converter which locally converts gray level of at least one of said divided small area of said first pattern image and said divided small area of said second pattern image corresponding to said first pattern image to be substantially the same with each other;
• a defect detector which detects a defect of the sample by using said first pattern image and said second pattern image in which at least one of said first pattern image and said second patter image is adjusted in at least one of brightness level and gray level;
• and
• a communication means which outputs a result of the defect detector to an external storage or processor.