Defect inspection apparatus and defect inspection method

A defect inspection method using a defect inspection apparatus comprising an illuminating portion emitting light to a pattern, an imaging portion taking an image of the pattern, and an arithmetic portion inspecting a defect of the pattern, comprising:

• acquiring a plurality of first sample images by taking images of the pattern in a first sample under a plurality of optical conditions, the first sample having a defect in a first area of the pattern;
• acquiring a plurality of second sample images by taking images of the pattern in a second sample under a plurality of optical conditions, the second sample having no defects in the first area of the pattern;
• calculating a first difference between a first sample image taken under a first optical condition and a first sample image taken under a second optical condition, among the plurality of optical conditions;
• calculating a second difference between a second sample image taken under the first optical condition and a second sample image taken under the second optical condition;
• selecting the first and second optical conditions under which a difference between the first and second differences becomes largest, as a first and a second inspection condition;
• taking images of a location of the target to be inspected under the first and second inspection conditions to acquire a first and a second inspection image, and
• determining whether there is a defect in the first area of the pattern in the target based on a difference between the first and second inspection images.

A semiconductor device manufacturing method using a defect inspection apparatus comprising an illuminating portion emitting light to a pattern formed with a mask on a semiconductor substrate, an imaging portion taking an image of the pattern, and an arithmetic portion inspecting a defect of the pattern, comprising:

• acquiring a plurality of first sample images by taking images of the pattern in a first sample under a plurality of optical conditions, the first sample having a defect in a first area of the pattern;
• acquiring a plurality of second sample images by taking images of the pattern in a second sample under a plurality of optical conditions, the second sample having no defects in the first area of the pattern;
• calculating a first difference between a first sample image taken under a first optical condition and a first sample image taken under a second optical condition, among the plurality of optical conditions;
• calculating a second difference between a second sample image taken under the first optical condition and a second sample image taken under the second optical condition;
• selecting the first and second optical conditions under which a difference between the first and second differences becomes largest, as a first and a second inspection condition;
• taking images of a location of the target to be inspected under the first and second inspection conditions to acquire a first and a second inspection image, and
• determining whether there is a defect in the first area of the pattern in the target based on a difference between the first and second inspection images.