Resurrecting integrated circuits by cooking them.

[dwight]

Hi Sam
 On one of the projects I worked on, we had a lockup problem ( CMOS issue ). It would blow either the VCC or GND lead. We had a wire bonder in the lab. I'd remove the cap from ceramic chips and bond on a new wire. It would work fine until we sequence the power wrong and it would blow wire again. The CMOS technology guy stated they shouldn't do this but it still happened ( simulation vrs real world ).
I suspect those parts that have an open lead are bonding wire failures and not silicon failures. If you were setup to install bonding wires, it is technically possible to repair such failures. In a plastic part, that might be more difficult than a ceramic package.
Not all failures are bonding wire failures.
Dwight

________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Jeffrey S. Worley via cctalk <cctalk at classiccmp.org>
Sent: Thursday, July 25, 2019 12:08 PM
To: cctalk at classiccmp.org <cctalk at classiccmp.org>
Subject: RE: Resurrecting integrated circuits by cooking them.

Does this mean that, like me scratching a bit at the package to expose
enough nub of broken-off pin to get a blob of solder on to hold a new
leg made of wire can theoretically be extended to shaving off the top
of the package to expose the IC and then tack soldering the severed
wire back onto it?

This would probably require some serious equipment I don't have, but
sounds possible in extremity.

RSVP

YHOSvt.

** TNM **
Dwight said:

"Message: 6
Date: Thu, 25 Jul 2019 05:52:31 +0000
From: dwight <dkelvey at hotmail.com>
To: Pete Rittwage <peter at rittwage.com>, "General Discussion: On-Topic
        and Off-Topic Posts" <cctalk at classiccmp.org>
Subject: Re: Resurrecting integrated circuits by cooking them.
Message-ID:
        <
BYAPR01MB5608F4C8A3860C2A7D2BC172A3C10 at BYAPR01MB5608.prod.exchangelabs.com
>

Content-Type: text/plain; charset="us-ascii"

"Failure of the POKEY chip were likely bonding wire failures. Voltage
stress failures are not likely to self repair.
I would agree, the fix is likely temporary.
Many early chips used gold wire for bonding but later chips used
aluminum. Which is better is always a question. The pads on the die
were usually aluminum, while the package was often gold. These are
acoustically bonded.
One wonders if one put a capacitor on the lead with a non-lethal
voltage and used such a heating method, it might be able to arc weld
the wire back on. Using the method of heating might enhance the success
as well.
Dwight"