Erasing EPROM's inside plastic package
lar...@northwest.com
Steve Work wrote:
>
> Are there any techniques to erase OTP devices inside a package? These
> are devices which could be erased by shining UV light directly on the
> silicon. But this cannot be done as they are already packaged and were
> programmed in error.
>
> I've heard some talk that X-rays can be used, does anyone know the
> dose, duration, etc. which would typically be required. Some attempts
> have already been made with X-rays sufficient to view inside the chip
> (i.e. inspect it) without success.
>
> What about using cobalt-60 irradiation?
>
> Also, does anyone know of anyone who can do erasure like this
> commercially?=========
x-rays wont work. in order to erase the programmed cells (floating gate
technology), carriers must be injected or removed from the floating gate.
a "programmed" cell can be either a "1" or a "0", depending on the
internal chip logic. freezing the eprom isnt gonna work, since electron
mobility will decrease. heating it up wont work usefully either, even at
high (7V) voltage. leakage at hot temp and hi voltage would probably be
due to hole leakage (not electron!) because of the fabrication
technology.
what might work usefully is a beta particle source. the plastic package
would hv to be ground/filed thin on the top (marked side) and the beta
source placed directly on top of the device. there is no guarantee of all
cells being properly erased. you might end up programming all the cells!
(see programming algo above).
larryc
Michael A. Covington
lar...@northwest.com wrote:
: x-rays wont work. in order to erase the programmed cells (floating gate
: technology), carriers must be injected or removed from the floating gate.
If light works, _why_ won't x-rays work?
--
Michael A. Covington http://www.ai.uga.edu/~mc
Chairman, Computer Security Team, and
Associate Director, Artificial Intelligence Center
The University of Georgia, Athens, GA 30602-7415 U.S.A.
Oscar Mitchell
Richard Steven Walz wrote:
>
> In article <64q8hk$snb$1...@cronkite.cc.uga.edu>,
> Michael A. Covington <m...@aisun1.ai.uga.edu> wrote:
> >lar...@northwest.com wrote:
> >
> >: x-rays wont work. in order to erase the programmed cells (floating gate
> >: technology), carriers must be injected or removed from the floating gate.
> >
> >If light works, _why_ won't x-rays work?
> For all *I* know, a LOW enough energy X-ray MIGHT work, but the problem is
> that the higher the energy the more they tend to pass right through!! The
> capture cross-section for an x-ray and the silicon injection gate (quantum
> tunneling) is QUITE small, thus stats on capture are quite small. IF
> somebody injected x-rays into a container of a substance that could
> fluoresce them down to the right energy, though, it might work!! But then,
> I don't know if the QM stats on tunneling would be right for injection or
> escape by trapped charges. I don't think this question is fully answered
> yet. It will take someone savvy to x-ray fluorescence with a completely
> adjustable x-ray machine, both eV's and current all the way down to opaque
> wavelengths!! It may be a laborious process, but if successful, perhaps
> worthwhile. The question THEN is, do you have to leave an x-ray machine ON
> for a WEEK just to erase a stack of 300 OTP EPROMs, and doesn't that cost a
> pile in kWhrs and tube life or replacement??????
>
> Someone mentioned higher energy beta, (electrons), and that might actually
> work if the chip was ground down to almost onto the chip first. Again, how
> high the beta energy and how much to run a betatron and for how long??
>
> There are severe "not worth it" questions for all these methods. Why they
> have not found a material to pass UV well which can be par-thermal with
> plastic and thus hermetic for cheap yet, however much longer it would take
> to erase with UV, is beyond me, unless they really LIKE selling quartz!!
>
> It's likely intentional "planned obsolescence". Though the chip can be
> reprogrammed a thousand times!! It's a true pity!! They should at LEAST
> package them with an airdome over the die so someone could drill or grind
> it off!! It's a moral question, *I* think!! Silicon is cheap, but dopant is
> NOT, nor is it abundant often!! It shouldn't be wasted in a landfill after
> one programming cycle!! Maybe EEPROMs will overtake them soon enough.
> -Steve
>
> >--
> >Michael A. Covington http://www.ai.uga.edu/~mc
> >Chairman, Computer Security Team, and
> >Associate Director, Artificial Intelligence Center
> >The University of Georgia, Athens, GA 30602-7415 U.S.A.
> -Steve
> --
> -Steve Walz rst...@armory.com ftp://ftp.armory.com:/pub/user/rstevew
> -Electronics Site!! 1000 Files/50 Dirs!! http://www.armory.com/~rstevew
> Europe:(Italy) ftp://ftp.cised.unina.it:/pub/electronics/ftp.armory.com
FLASH technology is pretty nearly there
Regards,
O
Richard Steven Walz
Henry Spencer
In article <slworkEJ...@netcom.com>, Steve Work <slw...@netcom.com> wrote:
>I've heard some talk that X-rays can be used, does anyone know the
People have reported trying this. The basic answer is: it doesn't work,
even with very long exposures, at least not with readily-available X-ray
sources. As others have commented, there is a fundamental problem in that
the X-rays have no particular tendency to stop when they hit the silicon.
>What about using cobalt-60 irradiation?
Co60 emission is gamma rays, which are even more penetrating and hence even
more useless.
--
If NT is the answer, you didn't | Henry Spencer
understand the question. -- Peter Blake | he...@zoo.toronto.edu
Luis Yanes
On Wed, 19 Nov 1997 16:03:17 GMT, Henry Spencer <he...@zoo.toronto.edu> wrote:
> In article <slworkEJ...@netcom.com>, Steve Work <slw...@netcom.com> wrote:
> >I've heard some talk that X-rays can be used, does anyone know the
> >dose, duration, etc. which would typically be required...
>
> People have reported trying this. The basic answer is: it doesn't work,
> even with very long exposures, at least not with readily-available X-ray
> sources. As others have commented, there is a fundamental problem in that
> the X-rays have no particular tendency to stop when they hit the silicon.
I've tried this some years ago, with a X-ray generator from a non-destructive
test system.
With low dose the eproms didn't erase and with more dose I got they fried!
I don't do extensive testing, only a few experiments with old plastic
eproms, and some windowed. All without success.
--
73's de Luis
mail: me...@esi.us.es
Ampr: eb7gwl.ampr.org [44.133.41.18]
AX25: EB7...@EA7MU.EACA.ESP.EU
http://www.esi.us.es/~melus/
David L Pearce
Luis Yanes wrote:
> I've tried this some years ago, with a X-ray generator from a non-destructive
> test system.
>
> With low dose the eproms didn't erase and with more dose I got they fried!
>
> I don't do extensive testing, only a few experiments with old plastic
> eproms, and some windowed. All without success.
Say you had a plenty of power and plenty of money to waste . . . could you actually
build a accelerator for electrons that could erase a OTP EPROM without grinding or
other case modifications? Or would a beam that powerful melt the case anyway?
David
Spehro Pefhany
In sci.electronics.components David L Pearce <dlpe...@eos.ncsu.edu> wrote:
>.. could you
> build a accelerator for electrons that could erase a OTP EPROM without grinding or
> other case modifications? Or would a beam that powerful melt the case anyway?
There was a fellow here that reported success in erasing OTP micros using
a particle accelerator, it was some time ago, but within the last year or
two. y
--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Spehro Pefhany "The Journey is the reward"
sp...@interlog.com
Fax:(905) 332-4270 (small micro system devt hw/sw + mfg)
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Sam Goldwasser
> There was a fellow here that reported success in erasing OTP micros using
> a particle accelerator, it was some time ago, but within the last year or
> two. y
I tried that but the neighbors complained when the breakers at the substation
popped every time attempted to erase a PROM :-).
--- sam : Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Lasers: http://www.geocities.com/CapeCanaveral/Lab/3931/lasersam.htm
Usually latest (ASCII): http://www.pacwest.net/byron13/sammenu.htm
Mark Zenier
In article <slrn67o26e...@bart.us.es>,
Luis Yanes <me...@www.esi.us.es> wrote:
>On Wed, 19 Nov 1997 16:03:17 GMT, Henry Spencer <he...@zoo.toronto.edu> wrote:
>> In article <slworkEJ...@netcom.com>, Steve Work <slw...@netcom.com> wrote:
>> >I've heard some talk that X-rays can be used, does anyone know the
>> >dose, duration, etc. which would typically be required...
>>
>> People have reported trying this. The basic answer is: it doesn't work,
>> even with very long exposures, at least not with readily-available X-ray
>> sources. As others have commented, there is a fundamental problem in that
>> the X-rays have no particular tendency to stop when they hit the silicon.
>
>test system.
>
>With low dose the eproms didn't erase and with more dose I got they fried!
>
>I don't do extensive testing, only a few experiments with old plastic
>eproms, and some windowed. All without success.
Here's an old posting to the contrary. I also remember seeing an
old (1972 or thereabouts) Intel databook that gave an X-Ray erasure
spec for the 1602 EPROM (the OTP version of the 1702). But then
the 1702 was prone to forget things all by itself.
A vaguely remembered thread brought up the point that some parts
are designed to use a reference floating gate device to determine the
threshold of the storage. This is normally shielded by metal from
erasure by UV but would not be shielded from X-rays.
For a definitive answer, looking at various radiation resistance studies
from the mil-spec crowd should tell what various parts can take and
what damage would happen.
:
: Subject: Re: erasing OTP-eprom with X-rays
: From: "James P. Meyer" <jim...@acpub.duke.edu>
: Date: 1995/09/18
: Message-ID: <Pine.SOL.3.91.950918...@godzilla.acpub.duke.edu>
: Newsgroups: sci.electronics
:
: On 14 Sep 1995 pas...@cloud9.net wrote:
:
: > : we are currently working on this problem. We've got a stock of
: > : accidentially misprogrammed OTPs we would like to reuse.
: > : Feel free to e-mail me later in october, we should have some
: > : results then.
: >
: > a radio amateur / dentist friend tells me he tried it, and it didn't work.
: >
: I *have* erased OTP EPROMs and several brands of OTP
: microcontroler chips. It *does* work. I used the wasted radiation
: (mostly X-rays) from the linear accelerator here at the lab. Ten million
: dollars to erase a chip is a bit much, but it does illustrate that it
: does work. Your friend just needs a bit longer exposure. The data in an
: EPROM chip is pretty robust and you won't see an immediate result from
: hitting it with only half enough radiation, UV *or* X-ray.
:
: Jim "no sig" Meyer
Richard Steven Walz
In article <65hpqr$cim$1...@news.interlog.com>,
Spehro Pefhany <sp...@interlog.com> wrote:
>In sci.electronics.components David L Pearce <dlpe...@eos.ncsu.edu> wrote:
>>.. could you
>> build a accelerator for electrons that could erase a OTP EPROM without grinding or
>> other case modifications? Or would a beam that powerful melt the case anyway?
>
>a particle accelerator, it was some time ago, but within the last year or
>two. y
>
>=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>Spehro Pefhany "The Journey is the reward"
>sp...@interlog.com
>Fax:(905) 332-4270 (small micro system devt hw/sw + mfg)
>=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Okay, Spehro, you have GOT to chase this down then and tell us the particle
energy and how much exposure and how long, etc. So that it might be judged
as to worth-while or not for a PILE of OTP's that need erasure!! This COULD
be worth some MONEY to people!! PLEASE!! ;-)
-Steve ;->
Spehro Pefhany
In sci.electronics.components Richard Steven Walz <rst...@armory.com> wrote:
> Okay, Spehro, you have GOT to chase this down then and tell us the particle
Anything for you, Steve. Here is the relevant portion of the posting from
October 9, 1996:-
The person is James Meyer from Duke who must just not be following this
thread, because he posts here often: jim...@acpub.duke.edu
-------------------------------------------------------------------------
.... To erase an OTP device encapsulated in epoxy, it's only necessary to
find a wavelength of "light" that the epoxy is transparent to. I've
erased OTP PROMs and microprocessors with X and Gamma rays. There seems
to be a wide range between the level necessary to do the erasing and the
level that will damage the chip.
Of course, getting enough "light" at those wavelengths isn't
easy. I use the surplus, wasted, radiation from our linear accelerator
here at the lab.
Jim
-------------------------------------------------------------------------
I hesitate to bother him with requests for details on the dosage as I
don't have access to a particle accelerator just now.. ;-)
> energy and how much exposure and how long, etc. So that it might be judged
> as to worth-while or not for a PILE of OTP's that need erasure!! This COULD
> be worth some MONEY to people!! PLEASE!! ;-)
It could be worth money to us. You can't make tens of thousands of OTP's
with scores of different programs without accumulating a bunch of chips
that could use erasure. I would want to assure the reliability by some
means, but that would probably involve looking at leakage currents (on
cmos) for evidence of damage and perhaps some temperature cycling. Or
something else I might think of later in a suitably suspicious and surly
mood.
I have also seen some information on reliability of cmos under radiation,
including continous radiation (space applications) and "transient"
radiation (ugh). Some of the work that has been done in the areas of
soft and hard errors in semiconductors is classified, though it's not like
any credible enemy couldn't buy a chip and test it..
Dave Huisman
Interesting,
How would you unfuse broken links from programming using electrons, and
if you could, how would you direct the beam to the links ?
Probably better to use flah from the beginnning.
Spehro Pefhany wrote in message <65hpqr$cim$1...@news.interlog.com>...
>In sci.electronics.components David L Pearce <dlpe...@eos.ncsu.edu> wrote:
>>.. could you
>> build a accelerator for electrons that could erase a OTP EPROM without
grinding or
>> other case modifications? Or would a beam that powerful melt the case
anyway?
>
>There was a fellow here that reported success in erasing OTP micros using
>a particle accelerator, it was some time ago, but within the last year or
>two. y
>
>--
>=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
-=
ge...@scopesys.com
In the EARLY DAYS of Eproms, ( ie when they wre first available, one had to build one's
own programmer !!). Before we got a UV eraser, we used to take our Eproms down to the
local hospital, and put them under the X-ray machine there to erase them.
X-rays might be a possible solution for you, as they should pass through the plastic
enclosure, ( ie Not need a UV transparent window).
Geoff
Spehro Pefhany
In sci.electronics.components Dave Huisman <SPAMOFF_...@niwa.cri.nz> wrote:
> Interesting,
> How would you unfuse broken links from programming using electrons, and
> if you could, how would you direct the beam to the links ?
> Probably better to use flah from the beginnning.
OTP micros and EPROMs that we are talking about here are just identical
chips to the UV-erasable ones, except they are in an opaque epoxy package
rather than a ceramic package with a window. Maybe you are thinking of
bipolar PROMs which indeed do use links sometimes (and some use diodes
that are made into shorts). Neither of these could likely be repaired
without getting into the package. And even then it would be expensive
and time-consuming at best, and more likely totally impractical.
The kind of chip we are talking about stores data as a charge on the
(floating) gate of an MOSFET.
--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Pdelpriore
>OTP micros and EPROMs that we are talking about here are just
Please someone, OTP??
Paul
Spehro Pefhany
Pdelpriore <pdelp...@aol.com> wrote:
> >OTP micros and EPROMs that we are talking about here are just
> Please someone, OTP??
One Time Programmable. Yet another TLA **. ;-)
--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Spehro Pefhany "The Journey is the reward"
sp...@interlog.com
Fax:(905) 332-4270 (small micro system devt hw/sw + mfg)
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
** Three Letter Acronym
Tom Detogne
Anybody got plans for a particle accelerator? I have a couple dozen
eproms to erase. Seems that the cost of the erasing equipment is a
little extravagant for the return.
Arie de Muynck
>Steve Work wrote:
>>
>> Are there any techniques to erase OTP devices inside a package? These
>> are devices which could be erased by shining UV light directly on the
>> silicon. But this cannot be done as they are already packaged and were
>> programmed in error.
>>
>> have already been made with X-rays sufficient to view inside the chip
>> (i.e. inspect it) without success.
>>
>>
>> commercially?=========
The Swedish customs did it for free when I shipped lots of micro's
(OTP in plastic DIL) to a custromer over there. I had two return
shipments until I was smart enough to mark the packages with 'DO NOT
X-RAY, SENSISTIVE MATERIAL INSIDE'.
I don't know the dose, but I don't suspect a high level was used. I'm
still sitting on a pile of wrongly programmed chips, waiting for an
X-ray machine to recover them for trials.
--
Arie de Muynck
(remove '_despam' to reply)
ed ngai
Tom Detogne wrote:
> Anybody got plans for a particle accelerator? I have a couple dozen
> eproms to erase. Seems that the cost of the erasing equipment is a
> little extravagant for the return.
hi, why not go to the local kmart, or osh and buy a black lite.
i'm sure that 1 or 2 hr.s under a black lite will do the erasing.
cya
ed
John Lundgren
Arie de Muynck wrote:
> >Steve Work wrote:
[snip]
> >> What about using cobalt-60 irradiation?
> The Swedish customs did it for free when I shipped lots of micro's
> (OTP in plastic DIL) to a custromer over there. I had two return
> shipments until I was smart enough to mark the packages with 'DO NOT
> X-RAY, SENSISTIVE MATERIAL INSIDE'.
> I don't know the dose, but I don't suspect a high level was used. I'm
> still sitting on a pile of wrongly programmed chips, waiting for an
> X-ray machine to recover them for trials.
Er, umm, does your pile glow in the dark? If so, I wouldn't use them
for a seat, you know, it could be a problem. You may have to wear lead
clothing! ;-)
> --
> Arie de Muynck
--
@@@@@@@@@@T@h@e@@I@n@t@e@r@n@e@t@@w@a@s@@c@o@o@l@@u@n@t@i@l@@@@@@@@
@ John Lundgren Elec. Tech, Info. Tech. Svcs.| lundgrej <AT> mail @
@ Rancho Santiago Community College District | .rancho.cc.ca.us @
@ 17th St. at Bristol \ Santa Ana, CA 92706 |www.rancho.cc.ca.us @
@ My opinions are mine, NOT my employer's. |PGP key avail on req@
@ May all your days be blue skies and green lights, and spam-free @
@@@@@@@@@e@v@e@r@y@o@n@e@@f@o@u@n@d@@o@u@t@@a@b@o@u@t@@i@t@@@@@@@@@
Spehro Pefhany
Not through opaque black epoxy.. even the windowed ones don't erase
very well with the filteed type of 'black light'
If your skills at glassblowing, vacuum technology and the handling of high
voltages are up to snuff (or you want to bring them up to snuff), you
might want to look at:
Scientific American, August 1971, page 106 "Atom smasher, how to
construct".
IIRC, and it has been a few years ;-) , the energies he achieved were of
the order of 0.5 MEV. I have no idea if that would be appropriate for
this purpose.
It would certainly not be cost-effective unless you enjoy this kind of
thing and want to do it anyway.
Peter Z
A long time ago I though I read an article where one could erase
the OTP devices by baking them in an oven at a high enough
temperature to disrupt the stored charge, but not enough to melt
the case or disrupt the IC doping. The temperature would have
been within the range of a house-hold oven.
(I've never tried it)
>>Steve Work wrote:
>>>
>>> Are there any techniques to erase OTP devices inside a package? These
>>> are devices which could be erased by shining UV light directly on the
>>> silicon. But this cannot be done as they are already packaged and were
>>> programmed in error.
>>>
>>> I've heard some talk that X-rays can be used, does anyone know the
>>> dose, duration, etc. which would typically be required. Some attempts
>>> have already been made with X-rays sufficient to view inside the chip
>>> (i.e. inspect it) without success.
>>>
>>> What about using cobalt-60 irradiation?
>>>
Richard Steven Walz
In article <3480ACD6...@home.com>,
Tom Detogne <tdet...@home.com> wrote:
>Anybody got plans for a particle accelerator? I have a couple dozen
>eproms to erase. Seems that the cost of the erasing equipment is a
>little extravagant for the return.
No! You have "radiation" sources over-glamorized in your mind!:
Hell, even *I* know a guy with a scanning electron microscope that could
use just the beam against the right target to do a pile of them in an hour,
and it costs little to run it! I have helped rebuild a cheap homebuilt
SEM in my youth as a physics student!!
There ARE amateur plans around for particle accelerators which COULD do
say, a chip each several hours, well worth it for hobby use, BUT: I was
proposing we find an unused INDUSTRIAL particle accelerator (yes, they DO
sit around a lot, and no, some kinds have little to wear out), and see if a
commercial venture wouldn't like for people to PAY THEM a fee to irradiate
their OTP's a predetermined time per dozen or so in massive lots!! And no,
they DON'T use all the Wattage in New Jersey!! Particle accelerators use
high VOLTAGES, but the particle/photon flux is about that of a xmas tree
bulb!! So it MAY be DO-able!! Wouldn't YOU pay to have OTP uC's erased?
Say, $1 a toss? Maybe more for big things?? How about PLCC EPROMs in the
4 to 16 Megabit range? It's a dying prospect, the world HOPEFULLY going
with EEPROM, but as long as EPROM is both simpler to make, and cheaper,
there will be great PILES of them out there wasted!! There should be a
way! I HAVE studied Gamma and X-ray fluorescence, and it provides another
means for low yield X-ray sources to be useful, and they're cheap to build!
Merely collimate an X-ray beam with fluorescing material in the right range
for capture in these devices and even if you only save them once, it can be
worth it! Better than buying new ones of some things. I know some OTP's
aren't worth it. But some ARE!! So, as a physicist experienced in high
energy photon sources and their uses, I DO recall how to toss this stuff
together with a surprisingly small amount of seed money!! Or how to
experiment and determine for a lab with a decent cheap accelerator perhaps
used for X-ray stress analysis, whether and how it might be profitable, and
I KNOW *I'm* surely NOT the only one out there who knows this stuff! Almost
any BA/BS in Physics has played with this stuff in upper-div lab!!
If it sounds esoteric and wild-eyed, I assure you I have done it with these
two hands, and built x-ray sources out of old vacuum tubes as well! But the
cheap hunk of pipe and big transformer with a vacuum pump and x-ray emitter
target is fine for such a purpose, and that's cheaper than you can believe!
Radiation's not just for SDI-"Star Wars" anymore! ;-> A cruddy uncalibrated
supply of x-rays is precisely what you need for this cheap-shit backyard
industry!! And those are so easy it's absurd!
-Steve Walz
>> Spehro Pefhany "The Journey is the reward"
>> sp...@interlog.com
>> Fax:(905) 332-4270 (small micro system devt hw/sw + mfg)
>> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
-------------------
-Steve
--
-Steve Walz rst...@armory.com ftp://ftp.armory.com:/pub/user/rstevew
-Electronics Site!! 1000 Files/50 Dirs!! http://www.armory.com/~rstevew
Europe:(Italy) http://ftp.cised.unina.it/pub/electronics/ftp.armory.com
Richard Steven Walz
In article <34830234...@news.pi.net>,
Arie de Muynck <ademu_...@pi.net> wrote:
>>Steve Work wrote:
>>>
>>> Are there any techniques to erase OTP devices inside a package? These
>>> are devices which could be erased by shining UV light directly on the
>>> silicon. But this cannot be done as they are already packaged and were
>>> programmed in error.
>>>
>>> I've heard some talk that X-rays can be used, does anyone know the
>>> dose, duration, etc. which would typically be required. Some attempts
>>> have already been made with X-rays sufficient to view inside the chip
>>> (i.e. inspect it) without success.
>>>
>>> What about using cobalt-60 irradiation?
>>>
>>> Also, does anyone know of anyone who can do erasure like this
>>> commercially?=========
>
>(OTP in plastic DIL) to a custromer over there. I had two return
>shipments until I was smart enough to mark the packages with 'DO NOT
>X-RAY, SENSISTIVE MATERIAL INSIDE'.
>I don't know the dose, but I don't suspect a high level was used. I'm
>still sitting on a pile of wrongly programmed chips, waiting for an
>X-ray machine to recover them for trials.
>Arie de Muynck
----------------------------
Well, it sounds like anybody with a used security x-ray machine has
themselves a ready-made backyard business, just as *I* said in another post
here!! Anyone? I don't want to do it, I fool with other stuff these days!
By the way, that exposure could be sizeable, compared to human diagnostic
x-rays, don't pooh-pooh it at all!! They are shooting through light metal
and such!! And in real-time!! But the human diagnostic dose is trivial. If
you flew around in an airliner with a bunch of them, you'd likely erase
some inside of a few months to a year, or at least corrupt them!! And most
chest x-rays are equivalent to an airline flight in dosage.
Richard Steven Walz
In article <348392...@sprintmail.com>,
ed ngai <en...@sprintmail.com> wrote:
>Tom Detogne wrote:
>> Anybody got plans for a particle accelerator? I have a couple dozen
>> eproms to erase. Seems that the cost of the erasing equipment is a
>> little extravagant for the return.
>
>i'm sure that 1 or 2 hr.s under a black lite will do the erasing.
>
>ed
------
No. It won't. Ask questions if you don't know. Don't try to make up
answers. A "blacklight" has a filter coating that removes the mercury
frequencies of UV which can erase WINDOWED parts. OTP's are the same die,
but have no quartz window!! Cheaper that way, but a die that COULD have
been written hundreds of times is limited to ONCE! A germicidal aquarium
clear tube can be used, but don't look at it or shine it on your skin!!
They come in shrouds that let the water in and out but not that UV!!
They take only five minutes for the windowed parts!! They can't do OTP's
however!! OTP=One Time Programmable!! The black epoxy doesn't pass UV!
That's WHY we need an x-ray machine!
Alan MacDonald
In article <3480ACD6...@home.com> Tom Detogne, tdet...@home.com
writes:
> Anybody got plans for a particle accelerator? I have a couple dozen
> eproms to erase. Seems that the cost of the erasing equipment is a
> little extravagant for the return.
It's easy and cheap to generate soft X-rays. This is my
recollection of an amateur scientist column in scientific american
in the early 70s describing how to build a source of "copious
soft X-rays". (there was a book of articles from that column).
Sorry if I'm a bit hazy on the details, but I did build one
as a kid and it was no problem to get it working.
Find yourself an _old_ valve (vacuum tube) with metallic (magnesium?)
getter on the inside top of the glass envelope (and no top
anode cap) Tape some bacofoil on the top of the envelope;
this will be your anode. The valve cathode is your cathode.
The idea is that the getter acts as a target for the electrons
accelerated inside the valve. It's worth cleaning and drying
the valve carefully to minimise the risk of tracking along
the external surface.
As I recall, you don't even need to supply a heater
current, although in the version I built as a kid, I did
fire up the heater. Then all you need is a source of a few
100 kV at low current, which is no problem, except that you need
to wind your own inductors (I didn't, preferring to treat salvaged car
ignition transformers as consumables :-)
(the article also described or referred to a design for a
Tesla type HV generator).
The only real problem might be getting hold of old enough
valves -- the "modern" "minature" types might not cut it --
they are small enough that tracking along the glass envelope
would be a problem. Also, there may be a problem with the
getter (absence of? in the wrong place? innapropriate metal?).
Oh yes, I forgot to mention: the whole thing should be
encased in a lead box :-)
As I recall, there was also a design for a particle (proton?)
accelerator. You needed to build your own mercury pump
& 1MV Van de Graf, but there wasn't much more to it than that ;-/
Ah, them were the days, what's happened, is SciAm too responsible
to publish articles that these nowadays?
Mark Zenier
>> eproms to erase. Seems that the cost of the erasing equipment is a
>> little extravagant for the return.
>
>i'm sure that 1 or 2 hr.s under a black lite will do the erasing.
Nope. I did that once in my starving student days with fluorescent
poster lamp I bought from a friend. Took 3 1/2 days with the 2716
resting right on the lamp. (Depends on the filter, other people
have said that they never could get it erased). Poster lamps,
/BLB phosphor, peak at 350 nanometers and that's just too low.
Sunlamp type UV bulbs for tanning booths peak at 300 nanometers and
reportedly can do it in your time frame. Don't know the phosphor
code for those.
Germicidal bulbs, the clear ones, can do it in just a few minutes.
3 minutes or less with the one I have. These run at 258 nanometers.
Mark Zenier mze...@eskimo.com mze...@netcom.com
Walter Gray
In article <6601tb$gki$1...@news.interlog.com>, Spehro Pefhany <sp...@interlog.com> writes:
:In sci.electronics.components ed ngai <en...@sprintmail.com> wrote:
:> Tom Detogne wrote:
:> > Anybody got plans for a particle accelerator? I have a couple dozen
:> > eproms to erase. Seems that the cost of the erasing equipment is a
:> > little extravagant for the return.
:
:> hi, why not go to the local kmart, or osh and buy a black lite.
:> i'm sure that 1 or 2 hr.s under a black lite will do the erasing.
:Not through opaque black epoxy.. even the windowed ones don't erase
:very well with the filteed type of 'black light'
:
:If your skills at glassblowing, vacuum technology and the handling of high
:voltages are up to snuff (or you want to bring them up to snuff), you
:might want to look at:
:
:Scientific American, August 1971, page 106 "Atom smasher, how to
:construct".
:
:IIRC, and it has been a few years ;-) , the energies he achieved were of
:the order of 0.5 MEV. I have no idea if that would be appropriate for
:this purpose.
:
:It would certainly not be cost-effective unless you enjoy this kind of
:thing and want to do it anyway.
How about soft x-rays from a junk colour TV? Remove the scan coils and
turn up the brightness.
Walter
Disclaimer: My employer is not responsible for this stuff.