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May 2007

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Subject:
From:
Adam Seychell <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Adam Seychell <[log in to unmask]>
Date:
Wed, 2 May 2007 17:46:49 -0500
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On Mon, 30 Apr 2007 09:14:23 -0400, DDFRITZ <[log in to unmask]> wrote:

....
>Direct metallization will work on the holes and microvias with all these
techniques, but it will not work well with the third alternative above.  The
"knit rate" for copper electroplate over direct metallization is not fast
enough for most horizontal platers, and if you have NO foil on the board,
where do you start the copper electroplate from?  Direct metallization works
fine where you have two starting sheets of copper foil and only have to knit
the holes.  But it is exceedingly difficult where the is no starting foil
anywhere on the surface.
>
>

This is what I expected. I am not sure what the physical rate of the copper
growth front is for direct metalization ("knit rate"), but I suspect even if
one were to make several cathode contact points on the panel perimeter, then
it will just be too slow. And even if it could metallize the work piece,
there will be the adhesion problem as you say. 
Roughly how much time does it take to plate the wall of a 1.6mm length hole
using direct metallization ?  30s, 60s, 5min ? 

Adam

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