Patent ID: 9347891
Filing Date: 2016-05-24
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 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 an illumination aperture 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 and detecting an output beam emitted from the sample in response to the corresponding ray bundle of the incident beam impinging on the sample at the corresponding set of one or more incident angles; determining a defect detection characteristic for each aperture position based on the output beam detected for each aperture position; estimating a defect detection characteristic for placement of an aperture at each of a plurality of combinations of two or more aperture positions based on a basis set of the defect detection characteristic that is determined for each aperture position; and determining an optimum aperture configuration based on which aperture position or combination of aperture positions has the most optimum defect detection characteristic that is determined or estimated.