27 Jan
2006
27 Jan
'06
9:36 a.m.
From: "Eric J Korpela" <korpela at
ssl.berkeley.edu>
On 1/24/06, Chris M <chrism3667 at yahoo.com> wrote:
Hi
Most all of the older chips using 1 micron or larger structures
show enough information to make a chip by just looking at the
chip. Using polarized light, features such as the wells for
the transistors are quite clear.
Current day parts have many layers of wires and sometimes
entire planes of metal above the silicon. Still, methods
of deprocessing are used both for reverse engineering
and also for failure analysis.
Photon emission is used for debugging of failures today.
On current chips, it often requires deprocessing of the back
side ( bulk ) of the die so that the transistors them selves
are visible. This is a combination of mechanical methods
and FIB deprocessing.
Most every manufacture of silicon has access to this type
of equipment.
Just for information.
Dwight
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?
I don't know if features would be immediately identifiable, but with
some work it should be possible. I know of a company that was
attempting to build silicon debugger using a high speed image
intensified camera to watch photons emitted by the transistors as they
pass current. Should work for reverse engineering... Given a couple
years and $500,000 I could probably build you one.... Then again I
would imagine that the device is patented.
Eric