Lamar,

I'm not a board expert either. But I compensate that by saving  mistakes and
progress and I use my curious nose and my big ears. So, many years eggoo,  I
learned this from a certain Cormac Kissone (not joking, this is his name).
This is something to start with.

Quote:

'  When you speak about ionic contamination of electroless Tin, I suppose
you have done a  SIR  test?  Right? Now,  you need to be aware, that the SIR
readout showing ionic contaminations can be the result of oxides. These
oxides are  actually salts, and the salts will dissolve during SIR testing,
raising the conductivity and therefore be measured as a ionic contamination.
In order to avoid such misleads, it's necessary to reduce ionics to
virtually zero. Therefore, the board cleaning solution shouldl contain an
anti-tarnishing agent that inhibits the formation of oxides. '

If you fulfil this later, then Tin oxides was not the problem and  you can
have a cup of double espresso before next step.

Inge

PS. Indianapolis...saw a TV program about the sandstorms and the draught
that hit Great Plain and some more areas 1933, and continued for years. No
rain for 10 years. A 600 meter high and black as night wall arised in the
horizon. And after the draught, when the rains finally came back, the first
grass was eaten by millions of rabbits!  I guess noone at TechNet is so old
that he/she saw it with own eyes.




On 15 September 2011 16:06, Lamar Young <[log in to unmask]> wrote:

> Is there something inherent in the manufacturing process of electroless
> tin boards that could cause ionics to be continually extracted in an
> IPA/DI water solution?  Or something to be more aware of?
> I'm afraid that this may be too general of a question.  But, we have a
> customer that says all other board types have no issue with ionics except
> their electroless tin boards.  They have cleaned and not cleaned the
> boards with the same result.  It would seem that the ionics is not from a
> residue, rather something leaching out.
> Yes, they are using a bulk extraction system.  No, they have not performed
> IC so we don't know what ionic species are present.
>
> Any advice that can be provided would be appreciated since I am not a
> board process expert.
>
> Lamar Young
> Specialty Coating Systems, Inc.
> 7645 Woodland Dr.
> Indianapolis, IN 46278
> (317) 244-1200 Ext. 276
> www.scscoatings.com
>
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