In a message dated 10/01/1999 9:08:35 AM Central Daylight Time,
[log in to unmask] writes:

<< Hi Every One.

 I need information on Migration

 Question
 1.  What will cause Electrical Migration

 Reason :

 We are seeing Dendritic Migration between components

 As of now we are applying conformal coating trying to stop the migration.

 Question:

 1. Is there a rework to prevent this condition.

 2.  Any study or data out there on reliability as far as using this method
 to stop the migration.


 Any information at all will be greatly appreciated.
 If more information is needed please ask.  This is all I know as of now
 I will do my best to get what ever is needed. >>

Hi Nancy,

Electro-migration is caused by having some sort of contamination on the
surface of your boards, and when in a humid environment and under power, the
conditions are there to cause this. In simple terms, you have a anode, and a
cathode (the electrical potential), and the contaminated surface provides the
conditions to allow these conductive filaments to grow.

To prevent this, the assembly must be very clean. Coating will help, but only
if the board is clean...that's the most important thing.

-Steve Gregory-

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