Weight difference method can be used to measure thickness. You measure mass of the film before and after deposition. The difference will give you the the mass of the film (m). You know the area of the film  (A) and density (d) of the film material. By using following relation you can find out thickness (t):

t = m/Ad

The estimated thickness will be not be accurate as density of the material in bulk and thin film is different. 

If your film is transparent and has a different refractive index from the substrate, you can use color to estimate film thickness. This is often done for oxide and nitride films on wafers but the same theory applies to any transparent film. If you're trying to measure opaque films (like metals), you will need some sort of instrument even if it's just a volt meter to measure sheet resistance.

Hi,

to determine the thickness of your film, a measurement of some physical property which is directly related to the film thickness is indispensable. Possible techniques are UV-Vis transmission/reflection, spectral ellipsometry, AFM or profilometry.

If colour technique

If colour technique does not work you use a simple technique of measuring fringe width by making a thin wedge of air. You need only travelling microscope and sodium lamp. Take two smooth glass plate, deposit film on one of them at one end only. Put another glass plate over it, thin wedge will be formed. Use reflected light to see interference.

If you say without any instrument, I assume you mean without any direct measurement of the thickness.

If the film is not transparent, you can use a crude weighing/ density of the film technique, where you weigh the substrate, then deposit a tick film and then weigh the substrate and film. Using the film's density (within a first approximation of the material which you deposits bulk density) you can calculate the thickness.   

if you don't use any experimental setup, you need to now the density, mass and surface area of the coating and lattice parameters, you can do a roughly estimation, but this calculation based on the homogeneous and single crystal approximation without the substrate effects

I agree that the visual color inspection is the only method to determine thickness of transparent film deposited onto Si-wafer without using any additional equipment. You can easily find color charts for SiO2/Si system. If you are lucky you can find also programs for calculation of the color chart of other materials. Luck!

I agree with Dr. Altin.

You should easiliy find it by substituting your parameters into the formula:

If you know the resistance of your sample,

R=(ρL)/A    

A=w x h                w: width   h: thickness    L: length

If you are weighing films, you will need a scale with at least milligram resolution. A typical 500 ohm/square PEDOT:PSS film is about 18 microns wet which will weigh approximately 19 milligrams on a 24x40mm substrate. A typical platinum film will weigh only about 2 milligrams on that same substrate. To provide any precision at all, you will need to accurately measure at least to 0.1 milligrams.

Weight difference method can be used to measure thickness. You measure mass of the film before and after deposition. The difference will give you the the mass of the film (m). You know the area of the film  (A) and density (d) of the film material. By using following relation you can find out thickness (t):

t = m/Ad

The estimated thickness will be not be accurate as density of the material in bulk and thin film is different. 

I'm pretty sure a scale is considered an instrument.

Assuming that "without any instruments" means "just with your eyes", than two methods come to mind for estimating the thickness:

• from interference color, which presumes a knowledge of the thin film system under study, transparency of the film, knowledge of the refractive indices of thin film and substrate, sufficient indices contrast between film and substrate;
• from level of transparency (a kind of qualitative Beer law), which could work for semitransparent films, assuming that you know well its absorption, and use a transparent substrate;
• from the bending of the substrate, assuming that you know well the stress in the film being deposited, as well as the mechanical properties of the film and substrate (ex: bending of a thin strip of quartz after deposition; or estimating the radius of a polymer substrate rolling after deposition of a thin film on it).

Interesting question.

Dear, there are many methods to calculate the thickness of thin films, but each method depends on one instrument as less as, but without use any instrument you can use needle listed and from penetrate you can be know the thickness.

Try by weight method.

You can etch the film with its corresponding etching solution and note down the etch time carefully. From etch rate you can find the film thickness.

Dear S.D. Sartale

I want to ask about (m) in the equation, is it just the difference in weight with and without the film? I mean it represents the weight in grams, right? no need to multiply it by 980?

Considering m confused me a lot.

Best regards

Fayroz

@Dr A. Kumar Thank you very much for your feedback. However do you think it need to etch a piece of deposited film?

Without using any major instrument, weight difference method is easiest and roughest one. But in case of thin films, there will certainly be major error in the final thickness due to many factors, for example difference in density of bulk and thin film material, weighing machine resolution etc.

Perhaps the simple way is to find a fold somewhere in the film and measure its double-thickness in the instrument you are looking at it!

I remember that this could be done in the electron microscopy for carbon films or ultra-thin section material. Perhaps the simple way is to find a fold somewhere in the film and measure its double-thickness in the instrument you are looking at it! I remember that this could be done in the electron microscopy for carbon films or ultra-thin section material.

Weight difference method . You measure mass of the film before and after deposition. you will know the the mass of the film (M). You know the area of the film (A) and density (d) of the film material. By using following relation you can find out thickness (t): t = M/Ad. or you can use needle and from penetrate you can be know the thickness.

I too follow weight difference method.