>Subject: Re: grinding down chips was Re: QX10 graphics board
>
> > I don't know about grinding, but the guy at MIT who figured out the Xbox
> > innards did something of the sort (regardless, it's a great read):
>A guy I went to school with does this for Motorola. He gets chips back
>that are failing in the field and dissects them to find out what went
>wrong.
>I think the actual process involves shaving rather than grinding.
In the FA (Failure Analysis) lab at IBM, the "De-layering" process was
complex, with different
chemical and mechanical approaches or combinations, on different types
of layers.
Often, the objective was to find the actual site of a failure, and expose
the layer or layers involved, to try to find the actual physical reason for
the electrical or functional failure.
Sometimes this got complex, such as removing a minute particle of
contamination, and putting it thru a Mass Spectrometer to try to find out
what the heck it was. They had "Signatures" for various contaminants,
including, as I recall, cosmetics, human epithelial cells, dust mites,
various fabric fibres, etc.
Sometimes, they tried to keep the lower layers in working
condition! Partially delayered chips were sometimes operated, in a vacuum,
with a low-power scanning electron microscope as a probe. It was possible
to extract waveforms, or scan multiple points to create a logic-analyzer
type display. And the graphics were neat, with voltages from 0 to 5 volts
displayed as shades of gray.
As a test system designer, I thought this stuff was way cool, and I once
proposed building a complete test system that included and drove the
scanning electron microscope, and produced graphics displays in real
time. I estimated only $500,000 (including the software!). It got shot
down. 5 to 7 years later they spent over a million on a Siemens (I think)
system that did pretty much the same thing. Oh well.
Regards, Terry King ...On The Mediterranean in Carthage, Tunisia
terry at terryking.us
Any interest in IBM PC 300 XLs?
Free to local pickup in South Jordan, UT.
Email me if interested.
--
"The Direct3D Graphics Pipeline"-- code samples, sample chapter, FAQ:
<http://www.xmission.com/~legalize/book/>
Pilgrimage: Utah's annual demoparty
<http://pilgrimage.scene.org>
>From: "Joe R." <rigdonj at cfl.rr.com>
---snip---
>
> Also several months ago someone on this list mentioned that he worked in
>a shop that had a wire bonding machine and he frequently took "failed" ICs
>and replaced the failed bond wire and keep on using them. He said that some
>ICs had had the bond wires replaced numerous times.
>
>
---snip---
Hi
At a previous company I worked at we had a bonding machine
and we used a lot of EPROM's. Often one would ge put
in upside down and blow a bonding wire. I used to take
these and pop the top off and rebond a new wire for the
blown one. They always worked after that. I'd just
epoxy the lid back on. I think I still have a few
of these in my parts box someplace.
Dwight
>From: "Richard" <legalize at xmission.com>
>
>
>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?
>
>Aren't there chips (i.e. crypto) that are designed to be destroyed
>if they are disassembled? I don't know what they do to the package,
>but if I had an IC with an EPROM containing my crypto keys, I'd want
>the chip to self-destruct during an attempt to pry open the package
>:).
Hi
You've been watching too many James Bond movies.
Dwight
>From: "Eric J Korpela" <korpela at ssl.berkeley.edu>
>
>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?
>
>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
>
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
Hi
Check all cables near and going to the position sensor and carriage
motor. As the main board is on the back of the door any thing that moves
when the door is opened is also suspect.
Also inspect PCB's for cracks. The constant impacts when printing would
cause all of the usual vibration related problems. Heads suffered from
fibers from the ribbon getting up the pin holes in the synthetic agate.
Dump the head in a jar of absolute alcohol for a week. Change liquid if
particles seen.
Rod Smallwood
(ex Digital Terminals Product Line 1975-1981)
-----Original Message-----
From: cctech-bounces at classiccmp.org
[mailto:cctech-bounces at classiccmp.org] On Behalf Of Gordon JC Pearce
Sent: 24 January 2006 20:22
To: cctalk at classiccmp.org
Subject: Jittery LA36
Hi there,
I've finally got the ribbons for my LA36, unjammed the pins in the
printhead and it is printing. It's not quite right yet, though...
The printhead often jitters backwards and forwards, sometimes several
inches. When you hit "RETURN" it's obviously lost track of where the
head is, and slams it into the left-hand stop, where it sits obstinately
pressed against the spring.
Cleaning up the photosensor bit on the interrupter wheel seemed to help
a little.
Gordon.
This message is really targeted to Randy McLaughlin, who I hope
still subscribes to this mailing list. I can't reach you
directly by email, so I wished to try this forum.
I am attempting to find information about UCSD pascal and
stumbled across the references on s100-manuals.com. I was
attempting to retrieve the files, but the links for download,
sucn as
http://www.s100-manuals.net/Download/Apple2Pascal1%5B1%5D.1IntDisasm.pdf
do not appear to work. Would it be possible to get the files in
the UCSD pascal area somewhere? I'm rediscovering the UCSD
p-System, and any resources would be greatly appreciated.
If anyone has this (or other p-system) information that they
would like to send my way, it would be greatly appreciated.
Many thanks,
-Eric
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Anyone want one? Work is discarding out about 70 of them. There are
a fair number of associated cable dongles, but I can't promise that I
would be able to get a cable dongle for every ethernet adapter. For
the modems it looks like they all have xjacks.
In 1 hr. 20 min. is when the stuff is open for all, so please reply
promptly.
--
"The Direct3D Graphics Pipeline"-- code samples, sample chapter, FAQ:
<http://www.xmission.com/~legalize/book/>
Pilgrimage: Utah's annual demoparty
<http://pilgrimage.scene.org>
Gordon JC Pearce gordonjcp at gjcp.net
Tue Jan 24 14:22:27 CST 2006
>
>Hi there,
> I've finally got the ribbons for my LA36, unjammed the pins in the
>printhead and it is printing. It's not quite right yet, though...
>
>The printhead often jitters backwards and forwards, sometimes several
>inches. When you hit "RETURN" it's obviously lost track of where the
>head is, and slams it into the left-hand stop, where it sits obstinately
> pressed against the spring.
>
>Cleaning up the photosensor bit on the interrupter wheel seemed to help
>a little.
>
>Gordon.
>
Hi,
Test the free movement of the carriage when powered down and lubricae with
some sewingmachine oil on the guidance bars, between the printhead bearing.
There must be a resonable free movement.
Then adjust the sensor allignment at the carriagemotor, you will need a
dual channel scope connected to two test points on the logic board, as
discribed in the maintenance manual. I'am pretty sure the jitter is caused
by a misallignement, as I have fixed dozens of LA36 for this.
Unfortunately, I do not have any docs anymore, but to do the allignement
you have to:
1. Release the tension spring and remove the rubber belt from the motor.
2. appley constant power to the carriage motor. (To generate many pulses).
(don't remember if 5 or 12 volt, but it is discribed in the maint.man.).
3. Loosen the screws holding the sensor a bit so you can move it.
4. Position the sensor such, that the time-shift between the two pulses
from the sensor on your scope has the required value (15 ms?).
I dont remember the values, but that's in the books. It sounds complicated,
but it is actualley a very simple adjustment. Given the fact that I never
screwed it up... :-) But you need a scope.
Succes,
Frank
On Jan 26 2006, 21:21, Chuck Guzis wrote:
> On 1/26/2006 at 9:24 PM Richard wrote:
>
> >Aren't there chips (i.e. crypto) that are designed to be destroyed
> >if they are disassembled? I don't know what they do to the package,
> >but if I had an IC with an EPROM containing my crypto keys, I'd want
> >the chip to self-destruct during an attempt to pry open the package
>
> I don't know about grinding, but the guy at MIT who figured out the
Xbox
> innards did something of the sort (regardless, it's a great read):
>
> http://www.xenatera.com/bunnie/proj/anatak/xboxmod.html
>
> The operative term is "decapsulating"; if you google on it, you can
find
> some interesting stuff, like:
>
> http://www.smtinfocus.com/technical_papers_list.html
The javascript on that page doesn't work for me but if you google for
"mondex nitric acid" you'll find some good descriptions.
--
Pete Peter Turnbull
Network Manager
University of York
