Introduction to double-sided FPC and multi-layer FPC

The double-sided FPC has a conductive pattern made of etching on both sides of the insulating base film, which increases the wiring density per unit area. The metallized hole connects the figures on both sides of the insulating material to form a conductive path to meet the design and use functions of flexibility. The covering film can protect the single and double sided wires and indicate the location of the components.

Multilayer FPC refers to laminating three or more layers of single-sided or double-sided flexible circuits together, forming metallized holes through drilling and electroplating, and forming conductive paths between different layers. In this way, complex welding processes are not required. Multilayer circuits have huge functional differences in terms of higher reliability, better thermal conductivity and more convenient assembly performance.

1. Finished flexible insulating substrate

This type is made on flexible insulating substrate, and the finished product is specified as flexible. This structure usually bonds the two ends of many single-sided or double-sided microstrip flexible FPCs together, but their center parts are not bonded together, so that they are highly flexible. In order to have high flexibility, a thin and suitable coating, such as polyimide, can be used on the conductor layer to replace a thick laminated coating.

2. Finished soft insulating substrate

This type is made on flexible insulating substrate, and the finished products can be flexed as specified. This kind of multilayer FPC is made of flexible insulating materials, such as polyimide film, laminated into multilayer boards, which lose their inherent flexibility after lamination.