My two cents,
To perform the Electrical Test in a curve tracer is a must before decapping
the IC.
If it is not shown any evident damage, it would very hard to detect the
damage after the decapsulation.
If it is a multilayer die it would be harder.
The chemical that we normally use is the red fuming nitric acid, but in
order to perform faster de decapsultation we first use a mechanical tool to
remove some of the plastic above the die.
Regards
Alejandro
-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Tuesday, July 29, 2003 2:36 PM
To: [log in to unmask]
Subject: Re: [TN] Plastic IC Decapsulation...
Steve,
If you can get your hands on a curve tracer it can very quickly tell you a
great deal about the condition of your parts. Running a powered device
curve trace is even better. You'll almost always be able to see defects
like EOS / ESD / opens, and shorts.
With a datasheet and a known good part, you're all set. First, see what a
known good part looks like, then compare your "dead soldiers" with those
waveforms. It's a little tricky to learn how to use and interpret the CT
display, but it can be priceless when it comes to determining what's going
on in situtations exactly like the one you describe. Any outside lab around
you is also likely to have one, and for most parts, even a large BGA, it
doesn't take more than an hour or two.
Decapping is a valueable tool, but most often we do that after curve tracing
has given us some indication where to go looking inside the package and on
the die.
Bruce Tostevin
Benchmark Electronics
Hudson, NH
> -----Original Message-----
> From: Steve Gregory [SMTP:[log in to unmask]]
> Sent: Thursday, July 24, 2003 1:36 PM
> To: [log in to unmask]
> Subject: Re: [TN] Plastic IC Decapsulation...
>
> Hi all!
>
> We've been building an assembly here for quite a while, and just recently
experienced quite a bit of failures at ICT with one IC. Out of 50
assemblies, only 3 passed. The failures on the rest of them have been with
one IC at the same location.
>
> I've x-ray'ed the failed parts and don't seen any broken or missing wire
bonds, so I wanted to take a look at the die area to see if I could spot
something obvious.
>
> -Steve Gregory-
>
>
>
>
> I have done this a few times with a 1/8" end mill. It is easier to
clamp it tight if you remove the leads first.
> I'm curious too.
> Charles
>
> -----Original Message-----
> From: Dehoyos, Ramon [mailto:[log in to unmask]]
> Sent: Thursday, July 24, 2003 12:06 PM
> To: [log in to unmask]
> Subject: Re: [TN] Plastic IC Decapsulation...
>
>
> Steve:
> Do you want to decapsulate the IC to view ESD damage with
an SEM?
> Or what is the purpose? Just curious. You should be able to pry the
top off
> with a sharp thin blade by inserting it in between top and bottom
part of
> the casing ( notice a line ) or perhaps saw the top off with a
dremel saw .
> The IC itself is in the bottom part of the casing in a recessed
area, so no
> damage will occur to it.
> Regards,
> Ramon
>
> > -----Original Message-----
> > From: Steve Gregory [SMTP:[log in to unmask]]
> > Sent: Thursday, July 24, 2003 9:57 AM
> > To: [log in to unmask]
> > Subject: [TN] Plastic IC Decapsulation...
> >
> > Mornin' All!!
> >
> > Been rather quiet on the list over the past week or so, hadn't it?
Either
> > means everybody is on vacation, or everybody is so busy building
stuff
> > without problems that they don't have any spare time...like to
wish that
> > was the case.
> >
> > Anyway, about Plastic IC Decapsulation, is that something I could
do
> > myself? If so, what sort of chemicals would I use? Or is this
something
> > better left to be done by the people who do that for a living,
like
> > failure analysis labs?
> >
> > Thanks!
> >
> > -Steve Gregory-
>
>
>
>
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