Off-axis phase waveband plate-based interference microscopic detection apparatus

Abstract

The invention discloses an off-axis phase waveband plate-based interference microscopic detection apparatus including a 13.5nm extreme ultraviolet light source, a focusing waveband plate, a five-dimensional precision micro adjustment table, an off-axis waveband plate, an optical fiber point diffraction device, an extreme ultraviolet bright field CCD and an extreme ultraviolet dark field CCD. The off-axis waveband plate is a hollow phase type structure, can realize modulation of + 1 level diffraction light, when the light is incident on sample surface, scattering and reflection occur simultaneously, the off-axis waveband plate takes effect on reflected light and scattered light, the reflected light is modulated into axial focusing, and the scattered light is reflected to the dark field CCD; the optical fiber point diffraction device provides reference light for testing light, interference of the reference light and the testing light is realized, an interferogram enters the bright field CCD, and the interferogram is interpreted by a computer for reduction of contour information of a to-be-tested sample. The off-axis phase waveband plate-based interference microscopic detection apparatus has the advantages of simple structure, good vibration resistance, high precision, low system cost, simultaneous bright field and dark field analysis and timely positioning and analysis of phase defects, and can obtain defect contour information.

Description

technical field [0001] The invention belongs to the field of optical interference detection, in particular to an interference microscopic detection device based on an off-axis phase zone plate. Background technique [0002] Photolithography is to transfer the pattern on the mask plate to the photoresist coated on the surface of the silicon wafer by exposure method, and then transfer the pattern to the silicon wafer by developing, etching and other processes. Extreme ultraviolet lithography (EUVL) is a next-generation lithography technology that uses extreme ultraviolet light (EUV, =13.5nm) as the exposure wavelength and is oriented to the 22nm node, or even below the 22nm node. Since any substance has absorption characteristics for EUV (13.5nm), a reflective reticle must be used in the exposure process, otherwise the reticle will absorb most of the EUV, resulting in insufficient exposure of the photoresist. A typical EUV reflective reticle is coated with a Mo / Si multilayer ...

AI Technical Summary

Problems solved by technology

The problem of introducing reference light is solved, and the processing of the off-axis zone plate is easier to realize than the bifocal zone plate; the off-axis phase zone plate interference microscope detection device can analyze bright and dark fields at the same time, improving the detection phase defect precision

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