I.Principle of thickness measurement.  

Both the first phase of thin film deposition and the latter stages of testing and failure analysis in microelectronics and MEMS place a significant emphasis on thickness measurement. The usage of organic semiconductors in microelectronics brings forth unique new issues with film deposition and monitoring.                                          

The spectral reflectance measurements' precision was assessed to be 0.1 nm, which was enough to prove a strong relationship between shock-generated light and glue thickness (Marshall, 2010).

With the use of a spectrometer, it is simple to determine the thickness of a single-layer film. That this is feasible for film with thicknesses between 1 nm and 250 μm (according to the TS series), and that measuring of the film's refractive index is necessary.

the fundamental concept behind measuring film thickness as opposed to reflectance. There will be interference between the light reflected from the incident surface (A) and the light reflected from the opposing surface (B) when light strikes the film at a fixed angle, resulting in an interference spectrum with alternately bright and dark fringes.

By inferring from the optical path difference expression, it is possible to determine the film thickness by counting the highest (or lowest) fringes of the reflected interference spectrum within a specific wavelength range.

Here, "d" stands for the film's thickness, " Δ m" for the number of peaks in the calculation's wavelength range, "n" for the refractive index, " θ " for the angle of incidence with regard to the sample, and " λ 1" and " λ 2" for the calculation's initial and final wavelengths.

To reduce sample damage during measurement, thin film thickness measurements employing non-destructive non-contact reflectance interference spectroscopy are used.

It is possible to assess rough surface coatings, film flaws, and film thickness using reflective interference spectroscopy. It is suited for monitoring a variety of components in industries including semiconductor, medicine, and industry.

II. Recommended System

For helping measure thickness of film easier, we have researched and developed TS series:

The TS Series is a versatile and configurable thin film measurement system that uses spectroscopic reflectometry to accurately determine optical and non-optical thin film thickness. This series is suitable for various semiconductor, medical and industrial applications.

The systems of the TM series measure anti-reflective coatings, anti-scratch coatings and rough layers on substrates such as steel, aluminum, brass, copper, ceramics and plastics. The thin film reflectometer system of the TM series can analyze the thickness of optical layers from 1nm to 250μm. A single thickness can be observed with 0.1 nm resolution, and single- or multi-layer films can be analyzed in less than a second.

Specifications:

• Easy operation and rapid measurement
• Multi-layer measurement
• Customer-requested Spectral Range can be customized
• Measurement of substrates such as steel, aluminum, brass, copper, ceramics and plastics
• Easy on-line and in-situ thickness measurements with flexible optical probe assemblies

References:

Marshall, B. J. (2010). Glue Film Thickness Measurements by Spectral Reflectance. https://doi.org/10.2172/991875