/diy/ - Do It Yourself

Kinda autistic question i do not hope to find an answer but still interesting to ask:

Im trying to peel of the layers of chips to get to the correct layer to see how it is structured. I tried grinding little little with sandpaper but that's way to unprecise and random

See pic related and the marked layers, for example

What are the best methods to achieve that? Preferable not chemically because my commie government banned a lot of those to buy