Measurement method of thin film thickness and refractive index and system thereof

Abstract

The invention discloses a measurement method of a thin film thickness and a refractive index. The method comprises the following steps that a laser beam passes through a dispersing lens and forms dispersed light, the dispersed light is emitted into a sample, and a spectral confocal signal formed by the dispersed light which is reflected by a sample surface is acquired; according to the spectral confocal signal, an upper and lower surface distance difference of the sample is acquired, and a first relation of the upper and lower surface distance difference, an actual sample thickness and a sample refractive index is acquired; data processing is performed on the spectral confocal signal so as to acquire an interference signal, according to the interference signal, a surface optical path difference of the sample is calculated and acquired, and a second relation of an upper and lower surface optical path difference, the actual sample thickness and the sample refractive index is acquired; and the first relation and the second relation are combined so as to acquire the actual sample thickness and the sample refractive index. A technical problem of simultaneously measuring an actual thickness and the refractive index of a thin film material is solved. The invention also discloses a measurement system of the thin film thickness and the refractive index. The above effects are possessed.

Description

Technical field [0001] The invention relates to the technical field of optical measurement, and more specifically, to a method for measuring film thickness and refractive index. Background technique [0002] Thin film materials are currently widely used in many fields of high-tech industries, such as thermal insulation materials in micro-electromechanical systems and mechanical coatings in aerospace equipment. As the basic physical properties of thin film materials, the non-contact online measurement of its thickness and refractive index has important research significance and practical value. [0003] At present, the measurement methods for the thickness and refractive index of thin film materials in the prior art mainly include the angle measurement method and the reflection method. Among them, the angle measurement method mainly uses the relationship between the incident angle and the refraction angle of the light entering the material to be measured to measure the material. Th...

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Problems solved by technology

However, this method usually requires processing of the measured material, which is not suitable for online measurement

The interference method mainly uses the interference phenomenon of light to measure the optical path. This method mainly includes Fabry-Perot interferometer method, immersion method and optical coherence tomography, etc., but it requires known thickness or refractive index. Only one of the parameter values ​​can measure another parameter, and it is impossible to measure both at the same time

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