Patent ID: 9523646
Filing Date: 2016-12-20
CPC Classification: G01N

Claim Text:
1. A method of facilitating an inspection of a sample using an optical inspection tool, the method comprising: opening an illumination aperture of an illumination selector one at a time at individual ones of a plurality of aperture positions of an illumination pupil area, wherein the aperture positions are spread across the illumination pupil area; while each illumination aperture of the illumination selector is opened at each aperture position, directing an incident beam of the inspection tool towards the illumination pupil area and such illumination aperture manipulates the incident beam so as to selectively pass a corresponding ray bundle of the illumination beam at a corresponding set of one or more incident angles towards the sample; while each illumination aperture is opened at each illumination aperture position, configuring an imaging aperture to pass only one or more ray bundles that are scattered from the sample in a dark field inspection mode; while each illumination aperture is opened at each illumination aperture position, detecting the one or more ray bundles that are scattered from the sample and passed through the imaging selector; determining a defect detection characteristic for each illumination aperture position based on the one or more ray bundles that are scattered from the sample; estimating a defect detection characteristic for a plurality of combinations of two or more aperture positions of the illumination selector based on a basis set of the defect detection characteristic that is determined for each aperture position of the illumination selector and the one or more ray bundles that are scattered from the sample; and determining an optimum aperture configuration for the illumination selector based on which aperture position or combination of aperture positions has the most optimum defect detection characteristic that is determined or estimated from the one or more ray bundles that are scattered from the sample.