What are PCB Laminates
PCB laminates are one of the primary materials used in the manufacture of multilayer PCBs. PCB laminates are made by curing layers of a fabric with resins under pressure and temperature. Varying fabric thickness, material weaves, and resin ratios result in differing dielectric characteristics, final thickness, and flammability parameters.
What is the makeup of PCB laminate?
Generally, there are seven constituents that are used to manufacture a laminate:
- Support/reinforcement material – supplies mechanical strength and electrical properties (provides thermal and electrical insulation, high stiffness, insensitive to moisture, heat resistance) – example material: Woven glass (E-grade) fiber
- Coupling agent – bonds inorganic glass with organic resin and transfers stress across the structure (promotes adhesion and provides moisture resistance)
- Stiffener/Matrix – acts as a binder and load transferring agent (provides thermal stability with high tensile strength) – example material:Polyimide
- Curing agent – enhances linear/cross polymerization in the resin (improves compressive strength, impact strength, provides toughening effect)
- Flame retardant – reduces the flammability of the laminate – example materials: Halogenated (TBBPA), Halogen-free (Phosphorous compounds)
- Fillers – reduces dissipation (high frequency), thermal expansion, and cost of the laminate
- Accelerators – increases reaction rate, reduces curing temperature, controls cross-link density