The high rugosity may come partly from the scan parameters you used. You should try to make a much shorter scan centered around the step you are looking for with low scan speed and use the correction function on only one side of the step.

If you still cant see the step you can try AFM.

What is the expected thickness for your silver?

Dear Boyue Chen , I think the main source of problems might be the kapton substrate as you pointed. Often Kapton comes as a tape or sheets, and it preserves some of the curvature from the roll, which could be the reason of that apparent negative thickness you see and the valley shape of the whole profile. Even gluing the Kapton to a glass substrate can leave the kapton surface wavy due to local accumulations of glue, think that the peak-valley hight in your plot is around 14.5um, which looks like a lot but it is actually half or less the thickness of one human hair, so something easily caused by the uneven glue or some residual curvature remaining on the kapton.

I agree the advice by Rémi Rafael of trying to get just the step area between the kapton and the silver layer. May be you still will see the curvature but you are only interestested in thickness and the hight of the step would give you the value, assuming an uniform thickness of your Ag layer.

Using an stylus profilometer could do the job too, and it could be an alternative to AFM if the Ag film is too thick to use an AFM.

Depending on the thickness and size of the Kapton substrate, you can try to solve the problem of curvature with some techniques, for example:

You could use water as "glue" between the kapton and the glass, so that the kapton remains attached to the glass by capillarity... this option would work better with large or medium sized kapton sheets.

Another option could be to use a vacuum chuck to keep the kapton firmly attached to the flat surface (an excess of vacuum and a thin film of kapton could cause depressions in the places where the vacuum holes or channels are placed), In this case you would place the kapton directly over the chuck platform, without glass substrate.

It is strange the high rughness shown by the profile, both in the area of the silver layer and also in the kapton. May be it is a matter of the parameters or may be the surfaces really have that rugosity, but if this is the case, your silver layer has a rugosity close to the average roughness.

You could check that and also measure the step thickness by means of a SEM too.

Hope it helps.

As it is not becoming clear..how have you arranged the sample on holder? One can not reason out for such result.....curvature of kapton is possible due to strain in the deposited film too....second what is the reference line set for reference too...if it is not possible to measure on kapton...use any other substrate simultaneously to deposite film and carry out measurement...best of luck

Hi Rémi Rafael and Manuel Gómez , Thank you so much for your kind suggestion and detailed explanation. I will constrain the scanning area to be around the edge of silver and shorten the scanning length to see if it goes better. The silver pattern is inkjet printed so I cannot expect it to be uniform. In this regard I am more interested in the profile instead of simply thickness, but it seems that this will be difficult with this optical profilometer. Do you think this would be possible with optical profilometer?

The problem with the kapton is quite problematic. But it comes to my mind that we indeed have a vacuum plate. I will look into it further.

Thank you very much for your help.

Hi Jignesh G. Hirpara , thank you very much for your reply. I tried to glue kapton on the glass substrate. The reference should be the kapton itself, but it is quite non-recognizable from the plot. Due to the application I am afraid the silver should be deposited on flexible substrate, kapton, PET etc..

Any suggestion would be very welcomed. Thank you.

Hi Boyue Chen , thanks for your explanations about the inkjet printed silver, that explains the roughness of the silver layer. Actually your optical profilometer is giving you the profile of your sample and from the image you uploaded it clearly sees the difference between the kapton and the silver, so I would say that you can obtain the profile info you are looking for. The good news with an optical profilometer is that it allows you to get a mapping and the software let you obtain profiles in any direction. In my experience, optical profilometers work fine and for instace, it is possible resolve features in the range of 100-200nm. The advantage over scanning profiling methods: the optical devices are a lot faster, you can get the whole info in a single shot and also they let you deal with dynamic surfaces.

Let us know if the vacuum platform works. Good luck!

Regards

I believe optical profilometry is very performant for smooth enough surfaces (i include sputtered metals and other high rugosity deposition methods) but not satisfactory for powders. Inkjet printed silver may be somewhere in the middle depending on the sintering process. You may be able to obtain the step height but i doubt you will get a good idea of the printed geometry this way. I believe tilted or cross section SEM may be more adequate, in particular as a simple scalpel cut should yield a satisfactory cross section with a kapton substrate.