producing the printed circuit with controlled impedance, the impedance will be controlled by acting on the dimensions HASL of the tracks and the distance between them, i.e. the insulation. For a multilayer printed circuit with a specific stack-up, it must be taken into account that the internal tracks
The inscription of the printed circuit, called serigraphy or silkscreen for short, is done on the top layer of the PCB and HASL has the role of a reference indicator for the components on the PCB. Graphics and text on a circuit board's PCB are usually printed with
(two layers of copper on both sides of an insulating HASL board), or multi-layered (outer and inner layers of copper alternating with insulating layers). Among the multi-layer PCBs, the most common are the four-layer ones. The four-layer board has many more routing options in the internal layers compared to the two-layer