Example metal-core PCB stackup.
In the above board, the standard process for placing vias cannot be used because the metal core layer will create a short circuit. Therefore, a specialized drilling and plating process is used to route electrical connections between each side of the board. An alternate version of this board only has components, traces, and dielectric materials on one side of the metal core instead of on both sides, so this drilling/plating process is not needed.
Ceramic circuit boards can be designed as single-layer, double-layer, or multilayer boards using a specialized fabrication process. Typical materials used to fabricate the insulating layers are alumina, aluminum nitride, and beryllium oxide. Ceramic PCBs also offer very high thermal conductivity that is similar to that of metals. They also have lower thermal expansion coefficient compared to FR-4 laminates. For these reasons, ceramic PCBs may be used in environments where the board temperature is cycled between very high and very low values.
Through-Hole or Surface-Mount?
Some design companies will make a distinction between through-hole PCBs and surface-mount PCBs. This would suggest that designers have to choose between these two types of components and they do not have the freedom to use both types of components on the same PCB. This is incorrect; designers are free to use both types of components in their circuit boards as long as the board can be reliably fabricated.