Hello Tom,

I have plated Sn/Pb over nickel. I have also used a nickel sulfamate bath
operating at around 54C. I did not see dewetting after reflow.
The Sn/Pb plating was done immediately after the nickel plating. Following
the Ni electrodeposition, the surface was rinsed, dipped into a dilute
nitric acid bath, and then rinsed again.  The Sn/Pb plating was initiated
before the surface was allowed to dry. I was using a methane sulfonic acid
based bath for the Sn/Pb plating.

Best Regards,

Christine


At 12:38 PM 6/18/98 -0400, you wrote:
>     All:
>
>     Is there a preferred nickel I should be trying to plate solder on top
>     of? We're struggling with plating tin lead on top of nickel and it's
>     subsequent reflow after soldermask. Anyone have any suggestions? We're
>     seeing dewetting and I'm wondering how many others out there are
>     trying to do this. We currently use a nickel sulfamate bath, if that
>     has any bearing... I'm not sure of activators and such, but if you
>     think it's important, I'll find them.
>
>     Thanks in advance all...
>
>     Regards
>
>     Tom Bresnan
>     [log in to unmask]
>
>     PS. Please respond direct to me as well as to the forum. I'm presently
>     disconnected from the service.
>

********************************************************
Christine Lizzul Rinne
Graduate Student
Dept. Of Materials Science and Engineering
North Carolina State University
Box 7907
Raleigh, NC 27695-7907
(919) 248-1107 TEL
(919) 248-1455 FAX

NCSU
http://vims.ncsu.edu/matsci/

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