Again, you seem to mean chemical migration across the board's members. We have never had any problem that way, as Gold is much more stable than Silver. So is Copper, Lead and Tin. But, in a few cases we have in fact had Copper migrating into the Gold despite a very thick Nickel barrier. How? Explanation was poor Nickel covering on vertical line edges, near conductor foot on FR4. So Copper migrated out the side of the pads and appeared on top. Does not occur at room temp. Otherwise, we use to say, if you get migration, you have not read the first chapters in the designer's guides.  I recommend you to buy from ASM Morris E. Nicholson's 'Electronic Packaging and Corrosion in Microelectronics' . One of dozens of books describing migration. I suppose Werner has written some himself.  /Ingemar

-----Original Message-----
From: Justin Braime [mailto:[log in to unmask]]
Sent: den 16 mars 2000 23:07
To: [log in to unmask]
Subject: Re: [TN] Electromigration demonstration...


Here's another question for you...
How do HASL, Gold, and Alpha levelled boards compare with regard to electromigration?

Thanks

Justin Braime
------------------------
Process Engineer
Compuspec Industries Ltd
Auckland, New Zealand
[log in to unmask] <mailto:[log in to unmask]>

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