Adam,

Just to clarify this, are you talking about "slivers" or "whiskers"?

David A. Douthit
Manager
LoCan LLC

Adam Seychell wrote:

> I am looking at the possibility of making boards with electroplated tin
> finish (tin over copper). From  the experiments I've done so far with tin
> finished boards there exists a problem with tin slivers after etching. This
> same problem agrees with what people have mentioned in a couple of past
> posts on IPC TechNet forum regarding tin as the final finish. Etching
> undercut is unavoidable and therefore slivers will always be around. I am
> interested to know if people are successfully making such boards and if so
> what are they doing to minimize this problem.
>
> Some of the ideas are:
>
> 1) Follow with a solder reflow stage to remove the slivers
>
> 2) tin plate at minimal thickness so the slivers are too week to be
> supported and fall off during normal etching and rinsing cycles. Practical
> minimum plating thickness is about 1 um (40 micro inches). This idea doesn't
> sound very good going by what I hear about copper/tin migration and the poor
> solderability that can result over a period of time.
>
> 3) go over each board with a nylon brush and hope that no problematic
> slivers remain to cause shorts sometime down the track.
>
> I am just starting out with PCB fabrication and trying to learn more about
> the industry. Please excuse me for asking such basic questions.
>
> Adam Seychell
>
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