Sunday, March 6, 2011

MCU decapping for live analysis

I was decapping some PIC MCU's lately (PIC12F629, 18F4550, 18FC452, 16F876A, 16F84 etc) for live analysis. Mainly for training my hands on and some security bits erase.
I got the ideas from Sergei Skorobogatov's page and Bunny's blog the first one is one of the best sites i've ever seen on MCU security.

So i started.

One thing  was annoying was the YELLOW light from the stereoscope lightbulb, so i thought i change the bulbs with newer technology LED ones.
I purchased from ebay for about 2$ two festoon 36mm led lamps and plugged them in.
Surprise suprise!! The stereoscope has only a transformer without any other circuits and the led was only flickering at 50Hz. Damn!
I made a quick perforated board power supply with filtering using the 78S12 regulator and presto.
Note: Images show only the under side of the scope (which i do not use). There is also a LED lamp above. You can see part of the board with the regulator and heatsink (when you have the led's on it's barely some degrees over room temp).
I like it, now i can proceed!

I'm using a drill to create the first pit and to eat away most of the black rosin from the chip and then i use 70% Nitric Acid to burn through it. Nitric acid works best when heated around 70% and i found out that my pcb preheater works fine for this.

Stay tuned for more.

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