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I'm measuring thicknesses of ~15 μm nickel thin films electroplated on a silicon substrate. I only have access to a SEM for this task. I need to cut the samples to get a side view of the film. However, the nickel film is plastic and the silicon undergoes a brittle fracture. As a result the nickel film often detaches from the substrate near the fracture point before I have the chance to cut it, making imaging impossible.

How could I cut through both the plastic thin film and the brittle silicon simultaneously? I'm getting access to liquid nitrogen in a week or so with the intention of freezing the sample. Is there a ~room temperature process which would allow me to prepare samples meanwhile?

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Perhaps you need to improve the adhesion of your film. Various thing influence adhesion - binder layer, deposition conditions, surface treatments. Here is a random article that may help. https://www.researchgate.net/post/Why_chromium_thin_films_are_used_as_an_adhesion_layer_in_several_applications

Perhaps you could embed the substrate and film in something that supports the film, but is brittle. Then you could fracture the combination. E.G. Epoxy.

I have no idea if that would work. I was just thinking of biological samples that are sliced into extremely thin sections. You freeze them first. Then slicing is much easier.

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  • $\begingroup$ Improved adhesion would probably help. However, I need to analyze the films as they are. $\endgroup$ – Tapio Friberg Jan 28 '17 at 15:02
  • $\begingroup$ The epoxy worked pretty well, much better than the liquid nitrogen. The large change in temperature caused the relatively thick films to pop straight off the substrate! The samples were small squares of substrate with the films on top. Embedding the whole square in epoxy allowed me to cut the sample with a diamond saw without the silicon even fracturing. Tool marks were evident in the images but it gave me a estimate of the film thickness with the resources at hand. $\endgroup$ – Tapio Friberg Feb 2 '17 at 16:54
  • $\begingroup$ You break glass by scratching the surface, and then snapping it. Epoxy is like glass. Try that. You might avoid tool marks. $\endgroup$ – mmesser314 Feb 3 '17 at 5:05
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Your SEM facility might have the setup for a Focused ion beam generation. FIB can be used to cut thin film samples without fractures, in particular, to prepare cross-section samples for SEM.

Also, if you only need to measure thin film thickness, consider non-destructive measurements such as ellipsometry.

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