FR-4 epoxy glass fiber cloth substrate is a kind of substrate with epoxy resin as the adhesive and electronic grade glass fiber cloth as the reinforcing material. Its adhesive sheet and inner core thin copper-clad board are important base materials for making multilayer printed circuit boards. The epoxy glass fiber cloth substrate has higher mechanical properties, dimensional stability, impact resistance, and moisture resistance than paper substrates. Its electrical performance is excellent, its working temperature is high, and its performance is less affected by the environment. In terms of processing technology, it has great advantages over glass fiber cloth substrates made of other resins. This type of product is mainly used for double-sided PCBs and is used in large quantities.