Cutting silicon samples with plastic thin films

Question

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?

Answer 1

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.

Answer 2

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.