If you can get interference fringes in the transmission, you can get film thickness from Swanapoule method. You can also get optical parameters, i. e. , real and imaginary parts of the dielectric constant, absorption coefficient as a function of wavelength in addition to the thickness.

If you can get interference fringes in the transmission, you can get film thickness from Swanapoule method. You can also get optical parameters, i. e. , real and imaginary parts of the dielectric constant, absorption coefficient as a function of wavelength in addition to the thickness.

I have a nice paper but it is from brazilian journal of physics. but it is explaining very nicely please go through it. it may help full

following paper is measure through IR

http://dx.doi.org/10.1590/S0103-97332000000300006

following is measure through uv but reflection mode

http://www.shimadzu.com/an/uv/support/uv/ap/film.html

but using beer lamberts law, I dont have any referance.

your can use the following link

https://www.researchgate.net/post/How_to_calculate_refractive_index_of_a_thin_film_sample_using_transmittance_data

The Lambert-Beer`s law is not a solution because it referes only to the homogeneous solutions. Even for colloids it is not working properly.

Establishing the thickness with only reflection and transmission is tricky in my opinion.

I would suggest using SEM in a tilt mode to see the thickness of the layer. Or you can also make a scratch on your film (or deposit the film with some mask) and make an AFM experiment.

I see that people have already answered your previous question, and it seems that some has suggested the use of BL law already. Of course with some effort you can use BL, by first assuming that your copper layer is metallic. It will give you the order of magnitude, at least. Ph.

I read previous answers and as I noticed from your question that you have a transmission and reflectance.If you got the transmission curve you can use the max.T and min.T

that you got it already and use  a special equations to calculate the thickness.This method can be used if you had high thickness.I found a paper explaining how can one got the thickness of the film.You can search for thickness measurement using theortical formula and you can get it.

I would suggest using SEM in tilt mode to give you the thickness because AFM has some degree of inaccuracy due to the shape of the tip when moving across any surface feature.  You can also use reflectivity measurements (XRR or Elipsometry) for comparison,  however, fitting the spectral data can be tricky.

If the film is minimally transparent, you need to know the absorption coefficient of the material that makes up the film.

Before explaining in detail, some extra information is needed:

If you have observable interference spectrum, it is posible to apply reasonable methods based on a combination of reflectance (R) and transmittance (T) curves to directly obtain the thickness t (not necessary to  resort to absorption).

If you have no observable interference (because a very thin film, or highly absorbing or single wavelength) you must to know the absorption coefficient alpha to apply Lambert-Beer as alpha·t = Ln(T/(1-R)).

What's the case?

I have mo interference pattern and exactly how to calculate the the absorption coefficient alpha.

Dip the sample into acid to remove part of the film. Then use a profilemeter to measure the step thickness or measure it using a SEM.

use airwedge or michelson interference method to find the thickness of the coated film. or take TEM (CROSS SECTIONALLY.)