Ed, when building blind via boards, some board manufacturers just plate the
vias, rather than plating the lines on the entire external surface. They do
this with a specially designed mask. This "PTH plate only" process allows
better control over the thickness of copper of the lines on boards that
require controlled impedance.
  Hope this helps.


> ----------
> From:         Ed Cosper[SMTP:[log in to unmask]]
> Reply To:     TechNet E-Mail Forum.;Ed Cosper
> Sent:         Monday, November 29, 1999 9:38 AM
> To:   [log in to unmask]
> Subject:      Re: [TN] BLIND VIA FAB:
>
> Are you referring to double plating the entire external surface???
>
> Ed Cosper
> ABC
>
> ----- Original Message -----
> From: Brunker Ed <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Thursday, November 25, 1999 3:52 AM
> Subject: [TN] BLIND VIA FAB:
>
>
> > When fabricating PCBs with blind vias, are there any alternatives to
> double
> > plating the outer layers? What design for manufacturability issues are
> there
> > regarding this technology?
> > Regards
> > Edward Brunker
> > Principal Process Engineer
> > Sendo
> > Centrelink House
> > Small Heath Business Park
> > B10 0HJ
> > UK
> >
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