Copper clad laminate (CCL), also known as copper-clad laminate, is a product made of wood pulp paper or fiberglass cloth as reinforcing materials, impregnated with resin, and covered with copper foil on one or both sides, and then hot pressed. When used in the production of multi-layer boards, it is also called a core board (CORE).

　　At present, the copper-clad laminates available in the market can be mainly divided into the following categories based on substrate: paper substrate, fiberglass cloth substrate, synthetic fiber cloth substrate, non-woven fabric substrate, and composite substrate.

　　The circuit board prototype substrate is an insulating layer board composed of polymer synthetic resin and reinforcing materials; A layer of pure copper foil with high conductivity and good weldability is covered on the surface of the substrate, commonly with a thickness of 35-50/ma; Copper clad laminates with copper foil covering one side of the substrate are called single-sided copper clad laminates, while copper clad laminates with copper foil covering both sides of the substrate are called double-sided copper clad laminates; Whether the copper foil can be firmly coated on the substrate depends on the adhesive. The commonly used thicknesses of copper-clad laminates are 1.0mm, 1.5mm, and 2.0mm.