Hello all,

I've been reading through the archives and have gotten some interesting
information, but I'm still looking for more on buried resistors. I've
seen a lot about the Ohmega-Ply mat'l, and our vendor will do it for us,
but I'm concerned about the costs, especially since I need only about 1
dozen resistors. A lot of people have mentioned thick film technologies
such as carbon. How have the experiences been with this as a resistor?
What sort of tolerances can you hold, especially since it seems you have
to screen them on? Are there other application methods or materials?
Also, since we need our resistor on an internal layer, would we be able
to laminate other layers on top of it without affecting its performance?
If anyone has practical experience with this, I'd love to hear it.

Also, as a short term prototype (rather than the buried resistors), I'd
like to be able to have a multilayer circuit, but just leave a hole
between the outer layer and layer 2. It seems like it wouldn't be very
feasible to laminate it with a hole (although if it would, I'd certainly
consider it if someone can tell me how), so I was thinking it might just
be easiest to laser drill through the outer dielectric layer. Is it
possible to burn away a quarter inch square area of dielectric and leave
the circuitry untouched. How hard is this to do?

Thanks for the help...

Matt

Matthew Sanders
PWB Procurement Engineer, Trimble Navigation Limited
[log in to unmask]
Phone: (408) 481-7817
Fax: (408) 481-8590

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