I have seen something similar on immersion tin and silver boards. Our fab
shop told us it wouldn't happen on ENIG boards though because the process
is different.

Basically, plating bath rinse solution was trapped inside vias that were
partially filled with solder mask. Once we heated the boards at reflow, the
vias "erupted".

Cheryl Tulkoff
Phone:(512) 683-8586
Fax: (512) 683-8847
National Instruments
11500 N. Mopac Expressway
Building A
Austin, TX 78759-3504





             James Hofer
             <[log in to unmask]
             m>                                                         To
             Sent by: TechNet          [log in to unmask]
             <[log in to unmask]>                                          cc

                                                                   Subject
             11/02/2004 02:17          Re: [TN] Contamination on the
             PM                        fabs....


             Please respond to
                James Hofer
             <[log in to unmask]
                    m>






It almost looks like some sort of background plating associated with some
chemistry entrapped in the vias.


James Hofer
Director of Operations
Accurate Circuit Engineering
3019 S. Kilson Dr.
Santa Ana Ca. 92707-4202
714-546-2162 work
714-473-6127 cell
[log in to unmask]
----- Original Message -----
From: "Ken Patel" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, November 02, 2004 12:14 PM
Subject: [TN] Contamination on the fabs....


> Fab & Assembly Experts,
>
> I am seeing some kind of contamination to bare boards. I have put
pictures
> at Steve web site for everyone's review and here is the link.
>
>
>
> http://www.stevezeva.homestead.com <http://www.stevezeva.homestead.com/>
>
>
>
> Does anyone have seen similar kind of contamination? Is it some kind of
> corrosion? It looks outside of board to me but not sure as I have seen
the
> boards personally yet. Boards are processed Electroless Nickel Immersion
> Gold.
>
>
>
> Any help will be highly appreciated.
>
>
>
> Re,
>
> Ken Patel
>
>
>
>
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