Among the fiberglass cloth base CCL products, FR-4 CCL refers to a type of flame-retardant CCL with fiberglass cloth as its substrate material and with brominated epoxy resin or modified epoxy resin as its adhesive.

 

Through holes in substrate can be metalized, also called plated through hole so that circuit conductivity can be implemented between layers in double-layer pcb board or multi-layer PCBs due to the features of fiberglass cloth base CCLs including high strength, excellent thermal resistance, and high dielectric properties. Recent years have witnessed higher requirement of thermal resistance for substrates with the updating and upgrading of electronic products so that some of paper base CCL products have been gradually replaced by fiberglass base CCLs. As a result, FR-4 fiberglass base CCLs have upgraded into the category of the most massive utilization and quantity among all products based on CCLs.

Products based on FR-4 CCL gained massive utilizations and the largest quantity among all fiberglass cloth base CCLs owing to its advantages:

• PCB manufacturability;

• CCL manufacturability;

• Excellent electric insulativity; • Flame retardancy;

• Plentiful source;

Up to now, different products based on FR-4 CCL have been generated and developed due to different performance levels and the categories are undertaking gradual generation and development. The main products based on FR-4 CCL are displayed in the content below:

• Common FR-4: flame retardant fiberglass cloth substrate as substrate material, flame retardant brominated epoxy resin as adhesive.

• Mid-Tg FR-4: flame retardant fiberglass cloth substrate as substrate material, brominated epoxy resin with excellent flame retardancy as adhesive.

• High-Tg FR-4: flame retardant fiberglass cloth substrate as substrate material, brominated epoxy resin with better flame retardancy as adhesive.

• Lead-free soldering FR-4: flame retardant fiberglass cloth substrate as substrate material and brominated epoxy resin with excellent flame retardancy as adhesive. Due to high soldering temperature of lead-free solder, much higher requirements must be met by thermal decomposition of substrate.

• Halogen-free FR-4: flame retardant fiberglass cloth substrate as substrate material, flame retardant phosphating nitriding epoxy resin as adhesive.

• Mid-Tg (Tg150°C) halogen-free FR-4: flame retardant fiberglass cloth substrate as substrate material, phosphating nitriding epoxy resin with excellent flame retardancy as adhesive.

• High-Tg (Tg170°C) halogen-free FR-4: flame retardant fiberglass cloth substrate as substrate material, phosphating nitriding epoxy resin with better flame retardancy as adhesive.

• FR-4 CCL with high performance: flame retardant or non flame-retardant fiberglass substrate. This type of CCL features high thermal resistance and characteristic attributes, using fiberglass cloth as substrate material and using modified epoxy resin with extremely excellent thermal resistance, triazine/bismaleimide resin, polyimide resin, PPE resin, diphenyl ether resin, cyanate ester resin or polytetrafluoroethylene resin as adhesive.

• Prepreg: When fiberglass cloth substrate material is dipped into resin glue and then dried to Level B, prepreg is generated. It has two functions one of which is to be used for CCL manufacturing and the other of which is to be used as inner layer adhesive material in multi-layer pcb manufacturing . Although it’s not a type of CCL, it enjoys a large amount of sales.

• Additionally, there are High modulus FR-4 board, FR-4 board with low coefficient of thermal expansion, FR-4 board with low dielectric constant, High-CTI FR-4 pcb board, High-CAF FR-4 board, High thermal-conductivity FR-4 board for LED.