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Anyone making cheap ceramic substrate electronics

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tszaboo:
Now that we have PCB suppliers in China complete the race to the bottom, and making boards practically for free:
Do you know of any supplier that would do ceramic substrates and printed electronics with pooling service?

ch_scr:
I've taken apart peltier elements to get ceramic carriers with attached copper pads. Can be sawn to size with a diamond disk on a dremel in a water bath. The pitch fits 0805 SMD and even DIL components. Not precisely what you asked for, but if you could find the supplier, I guess that could be a lead?

dmendesf:
May I ask... why? (It's a genuine question)

ch_scr:
Mechanical stresses on components can influence their values. For a SMD component on a FR4 substrate (that have no lead to bend and take up the stress), these stresses can come from the difference in thermal expansion between the two materials, but also from the slight swelling when the epoxy of the FR4 takes up humidity. The effect of humidity is on the order of months and follows the seasons with a delay. This also effects e.g. voltage reference in plastic cases, all containing epoxy that reacts to humidity, putting pressure on the die inside. This is in part the reason why precision circuits (think 6 1/2 digits and beyond) might still use THT components and/or use hermetically sealed components or assemblies. Or have slots milled in the PCB to isolate such stresses. Another proposed way to deal with this is to mount the sensitive SMD components on a flex pcb - with it beeing much softer, the forces should be much lower. This points to a potential problem: given ceramics are much harder than FR4, if the ceramics are "too different" between the component and PCB, potentially the forces from thermal expansion could be even higher than with FR4.

dmendesf:
I remember Telecontrolli used to make very simple 433/315MHz radios over alumina substrate. They even had small coils and resistors made with thick film over it and laser trimmed. For me it seemed too much technology for a cheap product...

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