outer layers need to be covered with solder mask, the inner copper layers are protected by the adjacent substrate realizare imprimate cablaje layers. The soldering mask soldermask is made of a fluid substance like an ink and is applied in a thin layer similar to varnish on the entire surface of the printed circuit less
that can help users during assembly. It is used to mark component values, part numbers, test points, polarity, cablaje realizare imprimate etc. Screen printing does not influence the printed circuit and the possible problems that may appear may be slight discolorations due to the high temperatures for gluing the components, so they are only PCB
i.e. the insulation. For a multilayer printed circuit with a specific stack-up, it must be taken into account that the internal tracks with controlled impedance are cablaje realizare imprimate shielded by copper planes and for this reason only the thickness of the insulation between layers and tracks and the track thickness must be taken