Hello TechNetters/ Designers,

I'm working on my first design with flex on ceramic. A semi-rigid
board with a lot of SMD stuff (two copper layers) has to be TAB-like
hot bar soldered with its one-layer-flex-end to an Aluminiumoxide
ceramic substrate with AgPd traces (good old thick film technology)
and two wirebonded chips (one of them a pressure sensor) on it.
I need a not too expensive but reliable technology, because it will
be a mass product for automotive application under the hood (about
150° C max.). The whole assembly will be "folded" in a sealed
housing.

My question is, where can I find good design rules for both sides of
the solder connection? Solder depot on one or both sides? Solder
paste printing/dispensing? Which surface finish on the flex side?
HASL, chemical tin, NiAu?
Any experiences about the reliability of these constructions?

Thanks in advance, regards
Matthias Mansfeld
-----------------------------------------------
Matthias Mansfeld Elektronik
* Printed Circuit Board Design and Assembly
Am Langhoelzl 11, D-85540 Haar, GERMANY
Phone: +49-89-4620 0937, Fax: +49-89-4620 0938
E-Mail: [log in to unmask]
Internet: http://www.mansfeld-elektronik.de

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