Multilayer film thickness and optical characteristic detection method

Abstract

The invention discloses a multilayer film thickness and optical characteristic detection method which comprises the steps: S1, sequentially depositing a film on a substrate to form a multilayer film,and classifying the film of the multilayer film into a diamond film and a diamond film; S2, measuring an ellipsometric spectrum of the multilayer film; S3, judging whether the film is a diamond film or a diamond-like film, if the film is the diamond film, executing the step S41, and if the film is the diamond-like film, executing the step S42; S41, calculating by adopting a Cauchy model to obtaina full-waveband film optical constant and a film thickness; S42, selecting a transparent area of a section of film, and calculating by adopting the Cauchy model to obtain the optical constant and thickness of the film within the waveband range; S5, adding a dielectric constant oscillator model to the absorption spectrum region of the diamond-like film, and adjusting the amplitude and width of theoscillator according to the ellipsometry; and S6, judging the difference between the experimental value and the fitting value by utilizing an evaluation function MSE so as to determine the structure of the multilayer film and the optical constant and the film thickness of each layer of film, wherein the optical constant comprises a refractive index and an extinction coefficient.

Description

technical field [0001] The invention relates to the field of optical detection, in particular to a detection method for diamond-like carbon and diamond multilayer film thickness and optical characteristics. Background technique [0002] The diamond-like carbon film has good optical transparency (medium-wave infrared 3-5μm, long-wave infrared 8-12μm), corrosion resistance and other characteristics, and the refractive index is adjustable between 2 and 3, which is an excellent infrared anti-reflection function film. However, the diamond-like carbon film tends to generate extremely high internal stress during the film formation process, which will limit the thickness of the deposition and the service life and performance. Diamond thin films are widely used in optical devices such as infrared windows due to their high mechanical strength, high thermal conductivity, good wear resistance, corrosion resistance and high infrared transmittance. protective effect. Therefore, the mul...

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Problems solved by technology

[0004] In the existing multilayer film measurement systems, most of them focus on the detection of film thickness, such as CN208140036U disclosed in the Chinese patent database, an online multilayer film thickness measurement system, which measures the thickness of opaque substrates by laser triangulation and infrared To measure the thickness of the transparent coating, the measurement areas of the two modules are limited to the same position. This system can realize the simultaneous, high-precision and online measurement of the thickness parameters of the same area of ​​the multilayer film, but it does not involve surface roughness and optical characteristics. Measurement

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