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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