AN IMAGING SYSTEM IN REFLECTION MODE USING COHERENT DIFFRACTION IMAGING METHODS AND USING MICRO-PINHOLE AND APERTURE SYSTEM

摘要

An apparatus and method for imaging a reflective sample, particularly a patterned blank DUV, EUV mask, includes the steps of making an optical system; Exposing the mask to obtain a public image including a monochromatic image; And developing the optical parameters of the optical system associated with the aerial image in accordance with a micro pinhole system using scan coherence diffraction. The apparatus comprises: a) a light source 10, such as an EUV source, a DUV source, a BEUV source or an X-ray source, which may have a relatively low temporal or spatial coherency to emit a light beam 22; b) a first focusing element (12), such as a Fresnel plate or toroidal mirror, for focusing the emitted beam to a required degree; c) a mirror (16) for reflecting the focused beam towards a sample (6) to be analyzed, the beam having an angle of 2 to 25 degrees towards the sample (6) with respect to a normal vector of the surface of the sample , Preferably at an angle of about 6 [deg.], A mirror (16); d) forming a beam so as to be monochromatic compared to the light beam 22 initially emitted from the light source 10, by allowing the first aperture a1 to focus and block the beam diameter to a necessary degree, A pinhole aperture plate 18; e) the light passing through the first aperture a1 of the pinhole aperture plate 18 disposed upstream of the sample 6, for example, at the same angle as the incident light, such as 6 °, A mechanism 17 for displacing the sample 6 continuously or stepwise in a direction perpendicular to the normal vector of the sample surface so as to be able to analyze the sample 6 reflecting the beam; f) the pinhole aperture plate 18 has a second aperture a2 as a transparent window, the second aperture being disposed adjacent to the first aperture a1 and reflected by the sample 6 Said pinhole aperture plate (18) adjusting the diameter of the light beam by limiting the diameter of the beam; And g) a pixel detector 20 for analyzing the reflected beam passing through the second aperture a2.