John,

That thickness of gold can cause some heartburn under SMT's and
especially BGA's.  We use a dual gold process - 5-10 u-inches on
solderable surfaces and 30-90 u-inches on contact areas.  We create a
separate gold mask gerber for the thicker copper (and those features are
not on the edge of the board or just on a "GND" net).

We've had good results from TTM in the US and Multek in China.  I've
heard that the "safest" process is to use electroplating for both.  (I
leave that up to the Fab house.)

Hope that helps,
Cherie Litson, CID+
PCB Design Tech Lead
SonoSite, Inc.
 
IPC Certified Instructor
Office: 425-951-1306
Cell:    206-619-8844

-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Karl
Bates
Sent: Friday, August 24, 2007 2:38 PM
To: [log in to unmask]
Subject: Re: [DC] HARD GOLD BOARD HOUSE PRODUCTION QUAINTLY
RECOMMENDATION NEEDED

John,
I had a board that Sanmina did for us, hard gold on the whole thing.
I'm 
not sure of the thickness.
We think it may have caused us some poor solderability (fractures under 
BGA's).
Good luck.
Karl


From: John Wheeler <[log in to unmask]>
Reply-To: "(Designers Council Forum)" <[log in to unmask]>,

  John Wheeler <[log in to unmask]>
To: [log in to unmask]
Subject: [DC] HARD GOLD BOARD HOUSE PRODUCTION QUAINTLY RECOMMENDATION 
NEEDED
Date: Fri, 24 Aug 2007 14:28:53 -0500

Hi all,

Can someone recommend some price competivite board house that can do
HARD GOLD over the entire board. Can be state side or offshore. We are
looking at using 30 micro inches if we can get it at a fair price.

Thanks,

John Wheeler

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