Patent ID: 9348214
Filing Date: 2016-05-24
CPC Classification: G01N,G03F

Claim Text:
1. An extreme ultraviolet (EUV) mask inspection system, comprising: a light source adapted to generate EUV light along an optical axis; an illumination system adapted to receive the EUV light from the light source, the illumination system comprising a spectral purity filter (SPF), the SPF adapted to transmit a first portion of the EUV light along the optical axis toward a location for a mask, the spectral purity filter characterized by a first axis and a second axis, the first axis, second axis and optical axis being mutually perpendicular to one another, the filter comprising a projection system adapted to receive the first portion of the EUV light after it has illuminated the location and thereby form an image of the mask; a first detector array adapted to receive the image of the mask; and a second detector array to receive the second portion of the EUV light.