To make it simple:
- (update and appease -4 doubters)
The Raw Copper weight and Plating weight are separate thicknesses.
In a DWG to board shop you can either define EITHER the finished outer track conductor thickness or each variable where the sum is the finished thickness. It depends on your need for PTH type thickness which is done only by plating thickness.
For generic quality, to ensure good conductivity in PTH PLating = 25 microns of copper on the hole walls and it makes 25 – 30 microns (1mil) on the surface tracks.
So if we start with a typical 17.5 micron copper foil (0.7mil) it will be 40–42 microns(1.6mil) after processing.
Per IPC-6012, the barrel plating thickness varies from class to class. If you have a minimum barrel thickness of X mils minimum, then your external layer Cu will be base Cu + 1.3 to 1.44 of X.
Check with supplier capability and class of PTH barrels to determine plating thickness.
For EHF microwave surface finish must be smooth such as ENIG.
Base = Foil or copper clad FR4, + ext. Plating = Ext Finished thickness.
Differential ext= signal.
Zo= between layers.
Zdiff = between edges.
Never assume dilectric constant when working with FR4 with 1GHz+.
Never assume supplier quality on PTH and barrel thickness.
Never assume Zo is 10% unless it is tested (Electrical TDR) or you have verified with that supplier process.