Defect inspection method and apparatus
AssigneeHitachi High-Technologies Corporation
InventorsYuta Urano, Akira Hamamatsu, Shunji Maeda, Kaoru Sakai
Life of this patent
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Abstract
A pattern inspection apparatus is provided to compare images of regions, corresponding to each other, of patterns that are formed so as to be identical and judge that non-coincident portions in the images are defects. The pattern inspection apparatus is equipped with an image comparing section which plots individual pixels of an inspection subject image in a feature space and detects excessively deviated points in the feature space as defects. Defects can be detected correctly even when the same patterns in images have a brightness difference due to a difference in the thickness of a film formed on a wafer.
Claims18
A defect inspection apparatus comprising:
- a light source for emitting a laser light;
- an illumination optical system for illuminating a surface of a sample, on which patterns are formed, during one main scanning with the laser light from a direction that is inclined from the surface of the sample while controlling a polarization state of the laser light emitted from the light source;
- a condenser for condensing reflection light scattered from the sample to a prescribed direction;
- a detecting unit for detecting during the one main scanning, via a spatial filter, multiple polarization components of light that are condensed by the condenser;
- said detecting unit including a polarization detecting section for detecting at least S polarized and P polarized components of the light that is reflection scattered from the sample;
- and
- a signal processing unit for detecting defects on the sample by processing the S polarized and P polarized components of the light detected by the detecting unit,
- wherein the signal processing unit extracts feature quantities by using the processed S polarized and P polarized components of the light that is reflection scattered, and detects deviated points and defects on the sample.
A defect inspection method comprising:
- illuminating a surface of a sample, on which patterns are formed, during one main scanning from a direction that is inclined from the surface of the sample with a laser light that is emitted from a light source and whose polarization state is controlled;
- condensing reflection scattered light from the sample to a prescribed direction;
- detecting, via a spatial filter, at least S polarized light and P polarized light that is reflection scattered from the sample after being illuminated during one main scanning with the laser light;
- and
- detecting defects on the sample by processing the S polarized light and P polarized light detection signals corresponding to respective polarization components;
- wherein feature quantities are extracted using the processed S polarized and P polarized components of the light that is reflection scattered, and the defects are detected on the sample.
Dependencies are inferred from the claim text.