Ed,
Let me begin by stating we use a peroxide/sulfuric acid oxide replacement. We currently use
the Shipley Circubond Oxide Replacement. I like you have found the peel strengths to be lower
than those compared to a conventional oxide. Now with that out of the way, everything else so
far to me has performed better than conventional oxide.
First: the lower peel strengths have never seen any delam between layers. This includes
Neltec, Speedboard, Double treat foil, RTF, G-tek, Hi-Tg, and a few other FR4 like materials.
2: We found controlling copper weight loss to be much easier, thus helping us tighten our
constraints for controlled impedance.
3: All those claims of solder floats and the like have not been wrong yet too!!
We control our conveyorized line by copper etch rate, and line speed. The copper etch rate is
controlled by chemical analysis and automated replenishment. Incidently, we found that on
certain parameters of the pre-clean and pre-dip chemistries, that the chemistry has a much
wider operating window than expected. I contend that controlling the line speed can affect
surface color. Again, I have yet ot see performances decrease due to color variation.
Finally, this system isn't like a conventional oxide, in that it in fact removes copper, and
does not end up weighing more. It actually roughens the copper by microetching. And, it then
passivates the copper with some type of organometallic copper complex. You'd have to read the
patents for more. I hope this helps. ..there is more, but I ramble already.
Regards,
Sean Clinton
Edward Szpruch wrote:
> We are considering replacing of our reduced black oxide and brown oxide
> innerlayer preparation by one of "conveyerised oxide substitions) .
> We made several preliminary tests and the samples were analysed by measuring
> of peel strength.
> The results were considerably lower compared to reduced black oxide
> laminated with epoxy prepreg and brown oxide laminated with polyimide.All
> "oxide substitute" suppliers reacted,that such results are expected,but
> performance of "oxide substitution" should be evaluated taking into account
> tests like solder float,steam test etc.
> I would like to ask PCB manufacturers,how they are controlling the
> properties of their "oxide substitution", especially on
> polyimides,thermount,RCC,teflon etc.
>
> Edward Szpruch
> Eltek , Manager of Process Engineering
> P.O.Box 159 ; 49101 Petah Tikva Israel
> Tel ++972 3 9395050 , Fax ++972 3 9309581
> e-mail [log in to unmask]
>
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