Hi,

Plastic packages are not hermetic.  Since water vapor is capable of 
penetrating the package it is a safe assumption that chlorine gas also 
would.  Once at the die, the chlorine would aggressively attack the 
unpassivated aluminum bond pads around the gold ball bond at the die. 
 Electrically testing the failed parts and finding open pins would 
support this theory.  Of course decapping the parts and inspecting the 
die would be the way to go to be sure.

Michael Contri
Digital Equipment Corp.
(508)-467-8797

Paul Terranova
[log in to unmask]
Phone: 508-467-3109
FAX: 508-467-6796

DIGITAL's Analytical and Environmental Test Services Lab
Digital Equipment Corporation
M/S: MRO1-3/D2
200 Forest Street
Marlboro, MA  01752


-----Original Message-----

Can anyone on TechNet help?
Thanks
Dave Bergman, IPC

---------- Forwarded message ----------
Date:	Mon, 16 Jun 1997 10:47:23 +0000
From:	Erik Ievins <[log in to unmask]>
To:	Dave Bergman <[log in to unmask]>
Subject:	Chlorine damage to electronics

Hi there.  This is additional information for the voicemail
message I left you earlier this morning.  Can you help me
get this question to the right person?  I would greatly
appreciate it.

We've got a situation where electronic circuit boards were
exposed to dry chlorine gas for several hours.  Many of
the IC chips have failed, but other than a few exposed ends
of copper wire turning brown, there is no visible evidence
of corrosion on the boards.  I know that there would likely
have been significant evidence if the ambient humidity had
been higher, due to formation of hydrochloric acid.

Can chlorine gas molecules penetrate the plastic IC housings and 
attack the tiny, gold connecting wires inside the chips?
Or is there some other explanation?
Thanks very much!
______________________________________________________________
Erik L. Ievins, technical consultant.
LWG, Inc.  (847)559-3008 ext 276


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