Method of inspecting mask, mask inspection device, and method of manufacturing mask

摘要

There is provided a method of high-sensitively detecting both of a phase defect existing in a mask blank and a phase defect remaining after manufacturing an EUVL mask. When the mask blank is inspected, EUV light having illumination NA to be within an inner NA but a larger value is irradiated. When the EUVL mask is inspected, by using a dark-field imaging optical system including a center shielding portion for shielding EUV light and a linear shielding portion for shielding the EUV light whose width is smaller than a diameter of the center shielding portion, the center shielding portion and the linear shielding portion being included in a pupil plane, the EUV light having illumination NA as large as or smaller than the width of the linear shielding portion is irradiated.

主权项

1. A method of inspecting a mask for reflecting extreme ultra-violet (“EUV”) light, comprising the steps of:
(a) irradiating the EUV light to the mask; (b) imaging the EUV light which reflects from the mask onto a light-receiving plane of an image detector through a dark-field imaging optical system to form a dark-field inspection image on the light-receiving plane; and (c) detecting a detection signal of a phase defect existing in the mask from detection signals obtained by the image detector, and the step (a) further including the steps of:
(a1) inputting information indicating whether an absorber pattern exists or not in an inspection region of the mask; and(a2) changing an illumination numerical aperture (“NA”) of the EUV light with which the mask is irradiated, depending on either a case that the absorber pattern exists or a case that the absorber pattern does not exist.