I would try a form of button plating (probably the wrong term, but the
process is similar), beginning with perhaps 2 ounce foil on the surface,
drill the holes, run through permanganate, electroless, etc etc, then mask
(with resist) the entire surface except for hole pattern, plate the holes up
to 2 ounce, strip the resist, apply the final image, finish the remaining1
ounce on the surface and in the holes.
Doesn't sound too impossible. Just make sure the plating tanks are able to
plate evenly, any dogbone effect in 3 ounce holes would be a mess I'm
sure...
Franklin
----- Original Message -----
From: "Lum Wee Mei" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Sunday, April 25, 2004 7:25 PM
Subject: Re: [TN] Stack-up for 2 layer, 3oz. copper board
> Roger,
>
> I would like to share what I have just discussed and learned from Robert
> while reading his book on "High Power Printed Circuit Design Notebook".
> He replied me on a similar question that I asked of him.
>
> He replied as "Typically, start with say 54ox of copper as a base and
> plate 6 to get 10oz on the surface an d6 in the hole. For some power
> boards that require more in the via/hole, he would start with 1oz and
> plate 9oz so the surface has 10 and the hole has 9oz."
>
> For you case, I guess it is not possible to have same copper thickness
> for both surface and thickness. Then, I may be wrong as your vendor
> should be able to advice. Hope my information can be of some help.
>
> Regards,
> Wee Mei
>
> Roger Alexander wrote:
>
> >Hello all,
> > I have a question concerning the stack-up for a 2 layer board in which
> >I need 3 oz. copper plating in the barrels. What copper foil thickness
> >should I specify? I want to insure that I get 3 oz. copper for all
> >lands/traces and in the barrels of all holes. I have never specified 3
> >oz. copper and didn't really know what is typically done for 3 oz.
copper.
> >
> >Thank you,
> >
> >Roger
> >
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