What is Coated Copper
Coated copper is a copper foil that has undergone a process of being coated with a dielectric material. This dielectric coating serves multiple purposes in PCB manufacturing. It allows for the direct bonding of the copper to the sub-composite material, forming a reliable conductive layer and provides insulation between different layers of the PCB, preventing short circuits and ensuring the integrity of electrical connections.
There are two main types of coated copper materials: wet processable and nonwet processable. Wet processable coated copper materials enable the formation of vias through acidic or alkaline etching. In this process, the dielectric material can be made etchable by photographic definition. On the other hand, nonwet processable coated copper materials utilize methods such as plasma, laser drilling, or mechanical drilling to form the vias.
The dielectric materials used for coating the copper foil can vary, with common options including epoxy, polyimide, or acrylic. These materials provide insulation and protect the copper traces from external factors such as moisture, dust, and electrical interference.