As I understand in a metal core PCB there's a copper layer, thermally conductive dielectric layer and then the metal layer for the heat dissipation. Can vias come to this metal layer so that it can act as the GND layer in a PCB design?
Electronic – Use the metal in a metal core PCB as the GND layer
pcb-layers
Related Solutions
You will hate yourself if you do stack up number two ;) Maybe that's harsh but it's a going to be a PITA reworking a board with all internal signals. Don't be afraid of vias either.
Let's address some of your questions:
1.Signal layers are adjacent to ground planes.
Stop thinking about ground planes, and think more about reference planes. A signal running over a reference plane, whose voltage happens to be at VCC will still return over that reference plane. So the argument that somehow having your signal run over GND and not VCC is better is basically invalid.
2.Signal layers are tightly coupled (close) to their adjacent planes.
See number one I think the misunderstanding about only GND planes offering a return path leads to this misconception. What you want to do is keep your signals close to their reference planes, and at a constant correct impedance...
3.The ground planes can act as shields for the inner signal layers. (I think this requires stitching ??)
Yeah you could try to make a cage like this I guess, for your board you'll get better results keeping your trace to plane height as low as possible.
4.Multiple ground planes lower the ground (reference plane) impedance of the board and reduce the common-mode radiation. (don't really understand this one)
I think you've taken this to mean the more gnd planes I have the better, which is not really the case. This sounds like a broken rule of thumb to me.
My recommendation for your board based only on what you've told me is to do the following:
Signal Layer (thin maybe 4-5mil FR4) GND (main FR-4 thickness, maybe 52 mil more or less depending on your final thickness) VCC (thin maybe 4-5mil FR4) Signal Layer
Make sure you decouple properly.
Then if you really want to get into this go to amazon and buy either Dr Johnson's Highspeed digital design a handbook of black magic, or maybe Eric Bogatin's Signal and Power integrity Simplified. Read it love, live it :) Their websites have great information as well.
Good Luck!
It can be done either way, but conventionally the surface layers are copper foil over prepreg.
Here are two different ways to do a 6-layer board:
The one on the right is the standard stackup style of every board house I've used.
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Best Answer
Theoretically not. By default, via enable the connection between the layers, but technologically they must be protected against contact of the vias with the metal core, because then it would cause a short circuit on the board (not every vias you want to connect with a metal core).
But theoretically, you can order a PCB with mounting holes through all layers (copper, insulator and metal core) and then you could connect such layers with, for example, screws or maybe some solder.
Source
But it's still best to ask a specific PCB supplier, because what will be impossible for one, for technologically expensive ones, it is possible to implement.