sanding a 556 timer IC to expose the die

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.


Amateur Electronics Design Engineer and Hacker

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