So tonight, just for the fun of it, I decided to sand, by hand, a 556 timer IC.
I just bought an extremely inexpensive microscope and was very interested to see what pictures I could get from it.
Unfortunately, for me, this was a trial and error process. I started with something like this:
and then after some sanding with 60grit sandpaper to remove basically the top half, this is what I ended up with
And then I switched to 320 grit, and after a couple of hours of sanding by hand, I ended up with
And then after some more time sanding, the center copper piece w/ what was left of the traces simply plucked off. I sanded and sanded more, but there was nothing left.
Now, just before this, I had just a center block of shiny copper, and then after some brief sanding ended up with some gray-ish speckled “layer.” I put it under the microscope and couldn’t see any pattern, couldn’t see anything discernible from just some scratches. I didn’t try putting it under a lot of power or anything, perhaps only at 80x or so — nothing in the least bit interesting.
I can’t help but now feel that I screwed up and should have tried that gray-ish layer under more power, I believe that might have been what I was looking for.
The After60grit image was sanded too far. The die has been removed from the carrier along with it’s bonding wires.