(no subject)

[randomdreams]

Tonight I learned how to reliably, repeatably remove the top of an integrated circuit package and expose the silicon without damaging it much, and without using acid. I'll do a writeup on @smellsofbikes later in the week, when I have a chip for which posting pictures online is permissible. I made a tiny vise to hold the chip, then I cut off 98.5% of the packaging material, then I hold it up to the bottom-side of a sideways flame so it's as cool as possible and gently bake the remaining epoxy until it's brittle, then oh so carefully scrub it off with a fiber brush and careful compression to fracture larger pieces using the tip of a pair of tweezers. That last bit, the careful compression, is by far the hardest, most nitpicky part. I'm using a 20x microscope and wish I had a 50x.

Comments

[secretagentmoof]

My cap's off to you, nyuk nyuk.

[armiphlage]

*groans*

Don't the wirebonds catch on the epoxy?

[randomdreams]

Yeah. They all get cut off pretty much at the top of the wirebond mound on the diepad. They stick up 10 mils and I'm cutting down well past that.
In fact, a few times (as it turns out under higher magnification) I tore off die pads when the mill hit the top of the wirebond mound and the die gave first.

[randomdreams]

hah!