The main material of printed circuit board (PCB) circuit board is copper clad laminate, and copper clad laminate (copper clad laminate) is composed of substrate, copper foil and adhesive. The substrate is an insulating layer board composed of polymer synthetic resin and reinforced materials; the surface of the substrate is covered with a layer of pure copper foil with high conductivity and good solderability, the usual thickness is 35-50/ma; the copper foil is covered on the substrate The copper clad laminate on one side is called a single-sided copper clad laminate, and the copper clad laminate with copper foil on both sides of the substrate is called a double-sided copper clad laminate; whether the copper foil can be firmly covered on the substrate is completed by an adhesive. The thickness of commonly used copper clad laminates are 1.0mm, 1.5mm and 2.0mm.

Commonly used copper clad laminates are as follows:

　　FR-1 ──Phenolic cotton paper, this base material is generally called bakelite (more economical than FR-2)

　　FR-2 ──Phenolic cotton paper,

　　FR-3 ──Cotton paper, epoxy resin

　　FR-4──Glass cloth, epoxy resin

　　FR-5 ──Glass cloth, epoxy resin

　　FR-6 ──Masked glass, polyester

　　CEM-1 ──Tissue paper, epoxy resin (flame retardant)

　　CEM-2 ──Cotton paper, epoxy resin (non-flame retardant)

　　CEM-3 ──Glass cloth, epoxy resin

　　CEM-4 ──Glass cloth, epoxy resin

　　CEM-5 ──Glass cloth, polyester

　　AIN ──Aluminum Nitride

　　SIC ──Silicon Carbide

　　G-10 ──Glass cloth, epoxy resin

There are also many types of copper clad laminates. According to different insulating materials, it can be divided into paper substrate, glass cloth substrate and synthetic fiberboard; according to different binder resins, it can be divided into phenolic, epoxy, polyester and polytetrafluoroethylene; it can be divided into general and special types according to the purpose. .