Franklin,

Could they be trying to achieve an 80/20 Au/Sn ratio for some high temp reflow operation?  I don't have any atomic mass/density info at my fingertips.  I know it sounds a little off the wall.  Must be a really high Tg laminate if they were.

Steve Creswick - Gentex



-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Franklin Asbell
Sent: Thursday, January 05, 2006 1:58 PM
To: [log in to unmask]
Subject: [TN] Gold over Tin


Received an unusual request for quote with a fab note callout for the
following.



1.      Plate 200/50 microinches SnAu (very hard)





Now I read that as 200 microinches of tin plating, followed by 50
microinches of Gold and thought to myself..huhhhh!!!



I contacted the buyer and he agreed it was quite unusual but they indeed
need gold over tin. The buyer could not explain why, so I thought I would
see if others have performed this process, and why such uncommonly mixed
coatings???



Franklin








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