@User you can do what you are suggesting using standard decapping and delayering procedures used by reverse engineers and authenticity validation. You use various acids (nitric, sulphuric, and sometimes hydrofluoric) to remove the metal layers. I believe there are chemical means to remove the oxide but when I've seen it done, it's usually via lapping. Here's a good summary https://revspace.nl/IC_Reverse_Engineering It's quite time consuming to do and not always perfect, you might etch too much or not enough, etc.