Ryan,

Tin whiskering has been a problem with immersion tin. There however have been
advancements in eliminating this problem. Atotech has added a step to the process which
prevents the growth of whiskers.

Sincerely,

Don Janus
Eastern Area Manager
Electronic Chemistry
Atotech USA Inc.

Frank Freitas wrote:

> Hello Ryan,
> There are numerous suppliers of this process currently, each with their
> strengths and weaknesses. I believe the greatest concern with immersion tin
> as final finish however is with tin whiskering.
> McGean-Rohco, Inc. (Cleveland, Ohio) has just recently presented a technical
> paper at the IPC Works which covers this and has developed a solution to the
> whiskering issue while at the same time allowing for immersion tin as the
> final finish. If you would like additional information please contact George
> Bokisa ( Technical Manager-Electronic Chemicals) @ 216-441-4900 in Cleveland
> and he will gladly provide you any assistance you may need.
>
> Regards,
> Frank Freitas
> Technical Sales Engineer
> McGean-Rohco, Inc.
> 2910 Harvard Avenue
> Cleveland, OH
> 216-441-4900
> ------Original Message------
> From: Ryan Grant <[log in to unmask]>
> To: [log in to unmask]
> Sent: November 3, 1999 7:42:27 AM GMT
> Subject: [TN] immersion tin as a surface finish
>
> Hi Technetters,
> Anybody using immersion tin as a surface finish?  What are some of its
> quirks?  We have a customer that wants us to use it, so we are going to
> qualify it as soon as we can get some boards in from multiple suppliers.
> During the qual, I would like to know ahead of time what problems to
> look for.  We are currently assuming it will be a drop in for our OSP
> and immersion gold boards.  (We got rid of HASL a while ago because of
> shorting on fine pitch is orders of magnitude high than gold).
>
> Thanks
>
> Ryan Grant
> Process Development Engineer
> MCMS
> (208) 898-1145
> FAX (208) 898-2789
> [log in to unmask]
>
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