Solder Mask

A solder mask is a thin protective layer applied to printed circuit boards (PCBs) that covers the copper traces while leaving exposed areas where components need to be soldered. It prevents solder from bridging between adjacent traces during assembly and protects the copper from oxidation and environmental damage. The solder mask is typically green in color, though other colors like red, blue, or black are also available, and it gives PCBs their characteristic appearance.