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 fisiere Gerber a fluid substance like an ink and is applied in a thin layer
fisiere Gerber a multi-layer board, an internal layer may be mostly solid copper to act as a ground plane for shielding and power return. For microwave printed circuits, transmission lines can be laid out in a planar form, such as stripline or microstrip, with dimensions carefully controlled to ensure consistent impedance. In RF and fast
copper as solid conductive areas for electromagnetic shielding or other purposes. Each of the conductive layers is designed with copper tracks (similar to wires on a flat surface) that provide electrical connections on that conductive layer. Another manufacturing process adds plated or metallized holes that allow interconnections fisiere Gerber between layers. PCBs mechanically support electronic components