Abstract: An optical inspection system for inspecting a patterned sample located in an inspection plane includes an illumination unit defining an illumination path, and a light collection unit defining a collection path, each path having a certain angular orientation with respect to the inspection plane. The illumination unit comprises an illumination mask located in a first spectral plane with respect to the inspection plane and the light collection unit comprises a collection mask located in a second spectral plane with respect to the inspection plane being conjugate to the first spectral plane. Arrangements of features of the first and second patterns are selected in accordance with a diffraction response from said patterned sample along a collection channel defined by the angular orientation of the illumination and collection paths.

Abstract: An optical inspection system for inspecting a patterned sample located in an inspection plane includes an illumination unit defining an illumination path, and a light collection unit defining a collection path, each path having a certain angular orientation with respect to the inspection plane. The illumination unit comprises an illumination mask located in a first spectral plane with respect to the inspection plane and the light collection unit comprises a collection mask located in a second spectral plane with respect to the inspection plane being conjugate to the first spectral plane. Arrangements of features of the first and second patterns are selected in accordance with a diffraction response from said patterned sample along a collection channel defined by the angular orientation of the illumination and collection paths.

Abstract: An optical inspection system for inspecting a patterned sample located in an inspection plane includes an illumination unit defining an illumination channel of a predetermined numerical aperture and first predetermined angular orientation with respect to the inspection plane, and a light collection unit defining a collection channel of second predetermined angular orientation with respect to the inspection plane. The illumination unit comprises an illumination mask located in a first spectral plane with respect to the inspection plane and defining an illumination pupil comprising a first pattern formed by at least one elongated light transmitting region having a physical dimension along one axis larger than along a perpendicular axis. The light collection unit comprises a collection mask located in a second spectral plane with respect to the inspection plane being conjugate to the first spectral plane, the collection mask comprising a second predetermined pattern of spaced-apart light blocking regions.