Why do We Use FR4 as Substrate for PCB?

  Nowadays, PCB becomes a very important part of majority of electronic products. The process of making PCB is selectively drilling holes, electroplating copper and other processing on the substrate which is copper clad laminate to obtain the required circuit diagram. So, the properties of copper clad laminate determine the quality of PCB. As copper clad laminate which is consist of copper and a substrate should have three functions: conduction, insulation and support, FR4 sheet has become the ideal material for copper clad laminates.

  The definition of fr4 comes from NEMA (National Electrical Manufactures Association) and FR stands for flame retardant. FR4 Laminate Sheet is a flame resistance material which is made of epoxy resin and fiberglass cloth under high temperature and high pressure. It is widely used in PCB as substrates because it has so many good properties such as high strength, flame retardant, chemical resistance, no water absorption and insulation. Specially, the water resistance of FR4 can allow PCB to be used in very humid environment.