It is the spectial coating with three main function: moisture-proof, fungi-proof and salt fog-proof.
It will become the clear protection film when solidified.
Nomally used to protect the quanlity of the printed ciucuit boards and the relative equipment
from contaminated by the environmental.
Before do the Coating, we need to clean and dry the goods, keep the goods flat.
Attenuate the coating, place at leat for 2 hours before operating.
The last is solidification in the high temperature furnace.

Yes, we can do SMT for ceramic PCB.

• For thick film technology, we can put resistor, electric capacity, conductor, semi-conductor, and interchangeable conductor on ceramic board, the value of resistors can be the same or different.
• For DCB technology, we can assemble LED, connector, resistor and other components on ceramic board.

Due to the conductor is different between thick film technology and DCB technology, the mothed of SMT is different, for thick film technology, the components are printed and sintered on board. For DCB technology, we assemble the components on ceramic PCB by SMT machine or by hand.

• Conductor (trace) Thickness: thick film ceramic PCB is 10~20um, DCB ceramic PCB is 0.1, 0.2, 0.3mm
• The conductor(trace) for thick film ceramic PCB is Au or AgPd, DCB ceramic PCB’s conductor is copper.
• Min trace width/space:thick film ceramic PCB is 300um (250um for prototype), DCB ceramic PCB is 0.3, 0.4, 0.5mm
• PTH (Plated Through Hole) is available for thick film ceramic PCB, but it is unavailable for DCB ceramic PCB now.
• 2 layers traces on the same top side and more than 4 layers traces for thick film ceramic PCB, but can not do this for DCB ceramic PCB now.

The thermal expansion coefficient (PPM/K) of Al2O3 substrate is 7.4 within 50℃-100℃

Normally, the copper base more thicker, the track should be more wider. One rule of thumb is that with a 18 µm copper base the track should not be narrower than 0.1 mm (4 mil) and with a 105 µm copper base the track should not be narrower than 0.25 mm (10 mil)

CAF (Conductive Anodic Filament) means that there will be an electrochemical reaction between the copper anode and cathode, which may result in an internal short circuit in the material.

This is a hole which is for multi-layer PCB that runs between one or more inner layers. They are normally mechanically drilled.

According to the new definition within IPC-T-50M a micro via is a blind structure with a maximum aspect ratio of 1:1, terminating on a target land with a total depth of no more than 0.25mm measured from the structure’s capture land foil to the target land.

Yes, in general, if you need the copper base thicker, the wider the track should be. One rule of thumb is that with a 18 µm copper base the track should not be narrower than 0.1 mm (4 mil) and with a 105 µm copper base the track should not be narrower than 0.25 mm (10 mil).

The answer is no, BT layer (Like as the FR4) and dielectric layer are very important, it is impossible to skip both of them or one of them.

Because the copper can’t be combined with meatal core, if we remove them, then we can’t make the trace on the metal base.

The other reason is the dielectric layer is most important for heat dissipation, normally, dielectric layer the thicker the better.