With the development of small, light, thin, multi-functional and high-density electronic products, the integration and assembly density of components on the boards are more and more higher, as well as power dissipation is more and more larger, so the heat dissipation has a great demand on PCB substrates. There will be overheated for the components on the board if the substrates have a poor dissipation, which will lead to the unreliability of whole machine. So the PCB substrate comes into being.
There are a lot of kinds of copper clad laminate based on different standard of classification.
- Classified by reinforcing material:
- Paper base CCL ( such as XPC)
- Glass fiber cloth base CCL (such as FR-4, FR-5)
- Compound CCL ( such as CEM-1, CEM-3)
- Special material base CCL (such as metal-base CCL, ceramic-base CCL and so on)
- Classified by applied insulation resin:
- Phenolic resin CCL (such as XPC, XXXPC, FR-1, FR-2 and so on)
- Epoxy resin CCL (FR-3)
- Polyester resin CCL
3. Classified by performance:
- General performance CCL
- CCL with high heat resistance
- CCL with low dielectric constant
- CCL with low CTE (Coefficient of Thermal Expansion)
4. Classified by mechanical rigidity:
- Rigid CCL
- Flexible CCL
What are the materials of copper clad lamination?
Copper foil: copper foil is a cathodic electrolytic material that deposited on a thin and continuous layer of metal foil on the base of PCB. And it’s easy ti bond to an insulating layer making a printed protective layer and create a board pattern with corrosion.
Prepreg: A prepreg (from pre-impregnated) is fibreglass impregnated with resin. The resin is pre-dried, but not hardened, so that it will flow, stick and completely immerse as heating. So prepregs are fibreglass strengthened by an adhesive layer (similar to FR4 material). as well as it’s known as the types of fibreglass.
Different manufacturers have different thickness in the types of prepreg, what’s more, there are the versions “SR” Standard Resin, “MR” Medium Resin “and” HR “High Resin based on the resin content. The best possible material is used depending on the desired final thickness, layer structure or impedance. The mentioned thicknesses are thus to be considered only as examples.