Copper foil is also one of the common components in electronic applications. It is a cathodic electrolytic material and a thin, continuous layer of metal foil deposited on the base layer of the circuit board. It serves as the conductor of the circuit board. Copper foil is a very thin copper product. The thickness of paper-like copper is expressed in microns. Generally between 5um and 135um, the thinner and wider it is, the harder it is to produce. Simply put, copper is pressed into very thin sheets, which is copper foil.