Apparatus and method for defect detection and program thereof

A method of detecting a defect comprising:

• (a) an image capturing step of capturing an image of a substrate;
• (b) a reference mask generating step of generating a reference mask image from an image of a non-defective substrate captured in said image capturing step;
• (c) an inspecting mask generating step of generating an inspecting mask image based on an image of an inspection object substrate captured in said image capturing step and said reference mask image, said inspecting mask generating step comprising the step of:
• (c-1) a step of tracing the contour of a pattern (“an inspecting pattern”) formed on said inspection object substrate by using a first contour sampler made of not less than three pixels, and smoothing the contour of said inspecting pattern based on a tracing trajectory in said contour of said inspecting pattern obtained by said first contour sampler;
• (d) a defect candidate sampling step of sampling a defect candidate region from said image of said inspection object substrate based on said inspecting mask image;
• and
• (e) a detection step of detecting said defect candidate region as a defect of said pattern based on characteristic features of said defect candidate region;
• whereby detecting a defect of said pattern formed on said inspection object substrate.

A program stored on a computer readable medium causing a computer to execute the followings:

• (a) an image capturing step of capturing an image of a substrate;
• (b) a reference mask generating step of generating a reference mask image from an image of non-defective substrate captured in said image capturing step;
• (c) an inspecting mask generating step of generating an inspecting mask image based on an image of an inspection object substrate captured in said image capturing step and said reference mask image, said inspecting mask generating step comprising the step of:
• (c-1) a step of tracing the contour of a pattern (“an inspecting pattern”) formed on said inspection object substrate by using a first contour sampler made of not less than three pixels, and smoothing the contour of said inspecting pattern based on a tracing trajectory in said contour of said inspecting pattern obtained by said first contour sampler;
• (d) a defect candidate sampling step of sampling a defect candidate region from said image of said inspection object substrate based on said inspecting mask image;
• and
• (e) a detection step of detection said defect candidate region as a defect of said pattern based on characteristic features of said defect candidate region.