Joe,
  Dataram switched from HASL to immersion white tin about 6 months ago.
We assemble our own products that consist of 99 44/100% SMT.
  The main reason for the switch was the flatness of the solder pads and
the overall board.  We were experiencing pins that were not soldered to
the board.  It was determined that the HASL was not level and that some
pins were not touching the solder paste.
  The white tin has worked very well for us.  There wasn't any increase
in the cost per board, but, not every fab house can do white tin.  The
solderability is just as good as HASL, and the shelf life is also
comparable.
  Overall we are very pleased with it.

   Regards,
        Brandon Luther


-----Original Message-----
From:   Joe Reichert [mailto:[log in to unmask]]
Sent:   Tuesday, July 13, 1999 2:27 PM
To:     [log in to unmask]
Subject:        [DC]

I sent this to TechNet, but I thought someone here
might have a comment too.

Our PCB house requested that we specify using a
White Tin coating over copper for improved solderability.
Has anyone had any experience with this before?
Solderability, Cost, Oxidation, etc...?
Thanks in advance,

Joe


All views and opinions expressed are my own and may
not represent the views and opinions of my employer.
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:::
Joe Reichert
mailto:[log in to unmask]

NorthStar Technologies, Inc.
A Lake Shore Company
575 McCorkle Boulevard
Westerville, Ohio 43082
Voice: 614-818-1150 Ext. 238
Fax: 614-818-1605
http://www.northstar-tec.com