Hi All!

I've learned about electromigration, and fortunately have never had a real
problem with (that I know about anyway). But recently, we've had some boards
returned to us that have failed for a short from VCC to Ground, usually at
the same area on the board.

It's beneath a keyed header that is hand soldered on the board. The first
couple of boards we got back, we couldn't find the problem. But we just got
back 3 more and I did see something. In trouble shooting we remove the header
(it's got a plastic body that has the plastic key molded into it) so we can
see if anything beneath the plastic.

Well, on one board today I think I saw something. There's traces that run
between the header pins and on one trace, it looked like the mask was not
adhered to the trace well. Then looking at it under higher magnification,
there was what appeared to look like these copper fern like structures
between the trace and the anular pad of the PTH on the laminate.

Will the dendrites be copper colored? All the pictures I've seen they have a
silvery gray to white appearance...I guess it would depend on which was the
cathode and which was the Anode in the scheme of things as to what the
dendrites would look like huh?

Has anybody else ever seen this?

Thanks ya'll!

-Steve Gregory-

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
##############################################################