1. Materials

1.1 Flexible circuits

There are many different materials available for flexible circuits, including polyesters, polyimides and fluoropolymers. These materials differ in terms of cost, thermal behavior, dimensional stability, tear resistance, flexibility, electrical characteristics and behavior in a humid environment. These characteristics are determined by the three constituent elements of the base materials, i.e. :

• dielectric support (polyester, polyimide, Teflon);

• the conductive layer (type of copper: galvanic, high ductility copper) ;

• the adhesive layer (acrylic or epoxy-based adhesive).

The characteristics of these materials are fully...