called a solder mask. Soldermask is generally green in color but can have different colors: green, red, blue, white, black. Only the outer layers need to be covered with solder mask, the inner copper layers are protected by the adjacent substrate layers. The soldering mask soldermask is made of
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 board, and often part of the internal layers are used as a imprimat pe Aluminiu circuit ground plane or power plane, to achieve better signal integrity, higher signaling frequencies, and better power supply
and a layer of copper foil, laminated to the substrate. Chemical etching divides the copper into separate conductive lines called tracks or circuit paths, pads for connections, metallized holes (vias) for passing connections between layers of copper as solid conductive areas for electromagnetic shielding or other circuit pe imprimat Aluminiu purposes. Each of the