grinding down chips was Re: QX10 graphics board

[Pete Turnbull]

On Jan 26 2006, 19:09, Eric J Korpela wrote:
> On 1/24/06, Chris M <chrism3667 at yahoo.com> wrote:
> >  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??? What if there
> > was some old chip for which there is no documentation.
> > If, given the availability of the proper equipment
> > (surface grinder?), you were able to take off say
> > .0001" of material at a time, or thereabouts ;), would
> > you have the ability to photograph it, and have
> > something in the way of a working schematic?

It's not done by grinding, but it can be done by dissolving the epoxy
encasulation in fuming nitric acid.  I found some good descriptions of
the process several years ago while researching the security problems
associated with Mondex.

-- 
Pete						Peter Turnbull
						Network Manager
						University of York