Microscopic differential reflectance spectroscopy measurement system and method for measuring thickness of nano film

Abstract

A microscopic differential reflectance spectroscopy measurement system and method for measuring the thickness of a nanometer film. The system includes a light source module, a beam splitter, a measurement optical path, a reference optical path, a monochromatic imaging module, and a data processing module; the light source module outputs non-polarized polychromatic Parallel light beams form two illumination beams through the beam splitter; one illumination beam enters the measurement optical path, converges and enters the sample to be measured; the reflected light beam on the surface of the sample to be measured passes through the measurement optical path and the beam splitter, and is first detected by the monochromatic imaging module. Optical microscopic image acquisition; another illumination beam enters the reference optical path, converges and incidents on the reference sample; the reflected light beam of the reference sample passes through the reference optical path and beam splitter, and the second optical microscopic image acquisition is performed by the monochromatic imaging module; data processing module The first and second optical microscopic images corresponding to different wavelengths are processed to obtain a differential reflection microscopic spectrum. The invention realizes real-time measurement of light intensity drift, and effectively suppresses common-mode errors based on differential optical measurement.

Description

technical field [0001] The invention relates to the technical field of optical in-situ characterization of nanometer film thickness and the technical field of nanostructure testing, in particular to a microscopic differential reflection spectrum measurement system and method for measuring the thickness of nanometer film. Background technique [0002] The in-situ measurement of nano-film thickness and the optical characterization and testing methods of nano-structure play an important role in the research and improvement of its technology. Among them, the differential reflection optical technology measures the reflectivity change caused by the surface reflection of the nano-film, and uses the optical model to study and analyze the film thickness and shape. [0003] The current differential reflectance optical measurement system is mainly based on spectral signal measurement, without a reference optical path, and needs to perform two measurements on the substrate, the combinat...

AI Technical Summary

Problems solved by technology

[0003] The current differential reflectance optical measurement system is mainly based on spectral signal measurement, without a reference optical path, and needs to perform two measurements on the substrate, the combination of the substrate and the nano-film, resulting in a very obvious drift of the measurement signal with the light intensity, and it does not have Microscopic or micro-area differential reflection signal measurement capability

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