Flexible circuits, also known as flex PCBs, are printed circuit boards that can be bent, twisted and folded because they have a substrate of flexible polyimide film and one or more thin layers of metallic material (usually copper). The copper layers are chemically etched to produce the desired circuit patterns. Adhesive is commonly used to bond the copper to the polyimide film, but other types of bonding can be used.
A via (also known as vertical interconnect access) is a copper plated hole that allows electrical connection between layers of a printed circuit board. The hole can be made using a drill or laser. A via consists of a barrel, a pad, and an anti-pad. Through-Hole Vias A through-hole via is a copper plated hole that traverses the entire printed circuit board from one top to bottom. It forms a