Thin film thickness and refractivity optical measurement method and its device

Abstract

The invention discloses an optical measurement method and devices used for measuring film thickness and refractive index. Light emitted out of a broadband light source generates an interference signal through interference structure, the spectrum information of the interference signal is detected and the fourier transform of the spectrum information is carried out, thus obtaining the optical path difference information of two optical paths which can generate the interference signal. Under known refractive index, a sample is arranged in an interference arm in the same type and is measured again, and the film thickness can be obtained by comparing the information of twice optical path differences. If the refractive index is unknown, the film is required to be rotated by an angle, and the refractive index and the thickness of the film can be worked out by the measurement of a third time. The optical measurement method and the devices used for measuring film thickness and refractive index adopt an optical method and have no damage to the sample; the resolution is micro level and the measured range can achieve millimeter level. Furthermore, the sample is not required to be strictly attached onto a sample platform; meanwhile, the information processing method is simple, and the information of the thickness and the refractive index of transparent or half-transparent film can be conveniently obtained in real time.

Description

technical field [0001] The invention belongs to the field of optical measurement, in particular to an optical measurement method and device for film thickness and refractive index, which are suitable for industrial detection of the thickness and refractive index of transparent or semi-transparent films (thin layers that can be penetrated by light). field. Background technique [0002] The film thickness is a key parameter to measure the quality of the film. At present, there are many ways to measure the film thickness, such as X-ray interference method and interference microscope measurement, but they can only be used to measure the film thickness, not the refractive index. Moreover, X-ray technology is rarely used in thin film production lines. X-ray tubes have short life and expensive replacement. Generally, they can be used for 2-3 years, and they are not suitable for measuring polymers composed of various elements. The signal source is highly radioactive and is often use...

AI Technical Summary

Problems solved by technology

However, due to the complex principle and operation of this method, it is impossible to use it for real-time detection

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