grinding down chips was Re: QX10 graphics board

J. Peterson pdp11 at saccade.com
Fri Jan 27 01:18:03 CST 2006


>I've been dying to ask this question. Can you
>actually learn something (hopefully a whole lot!)
>about a chip if you actually did this???

There are actually successful companies in just that business:
http://www.chipworks.com/

Be sure to click on the "Silicon Art Gallery" link at the top.  For a while 
Chipworks had a free CD with other interesting photos, I'm not sure if it's 
still available.

Getting at the die isn't all that complicated - it's called "depackaging" 
or "decapsulation" in the trade.  For ceramic and PGA packages with a metal 
lid, it's generally pretty easy to just pry the lid off.  For plastic 
chips, dripping fuming nitric acid on the package eats it away but leaves 
the silicon and bonding wires in tact.

There are labs that do this sort of work on a regular basis:
http://www.mefas.com/Decapsulation.htm
http://www.dpems.com/

Be sure to read bunnie's story of how to skirt the "security" features of a 
PIC microcontroller by sticking a tiny piece of electrical tape(!) on the die.

http://www.bunniestudios.com/wordpress/?page_id=40

Modern, high end chips (P4, Opteron, Cell, etc.) are pretty hard to get at 
though.  Rather than having bounding wires at the edge of the chip, they 
have tiny solder balls scattered across it.  The chips are soldered/glued 
face down directly to the package interconnect.  I'm sure it takes some 
serious wizardry to pry them loose again.

[Why yes, I am a chip collector...how could you tell?]

Cheers,
jp
http://www.saccade.com/




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