Summary： The substrates used in PCB are mainly divided into two categories: organic substrates and inorganic substrates. Among them, the organic substrates are made of several types of materials which refer to the reinforcing materials, such as glass fiber cloth, fiber paper, glass felt, etc. These reinforcing materials are impregnated with resin adhesive and dried, then covered with copper foil at high temperature and high pressure. This type of substrate, known as copper clad laminate (CCL), is the main material used to make PCB.
Introduction:
The substrates used in PCB are mainly divided into two categories: organic substrates and inorganic substrates. Among them, the organic substrates are made of several types of materials which refer to the reinforcing materials, such as glass fiber cloth, fiber paper, glass felt, etc. These reinforcing materials are impregnated with resin adhesive and dried, then covered with copper foil at high temperature and high pressure. This type of substrate, known as copper clad laminate (CCL), is the main material used to make PCB.
Simple Classification of CCL:
There are many varieties of CCL, which can be divided into many categories according to different classification standards, as shown below:
1 Classified by reinforcing material:
1) Paper base CCL (eg. XPC)
2) Glass fiber cloth base CCL (eg. FR-4, FR-5)
3) Compound CCL (eg. CEM-1, CEM-3)
4) Special material base CCL (eg. metal-base CCL, ceramic-base CCL etc.)
2 Classified by applied insulation resin:
1) Phenolic resin CCL (eg. XPC, XXXPC, FR-1, FR-2, etc.)
2) Epoxy resin CCL (eg. FR-3)
3) Polyester resin CCL
3 Classified by performance:
1) General performance CCL
2) CCL with high heat resistance
3) CCL with low dielectric constant
4) CCL with low CTE (Coefficient of Thermal Expansion)
4 Classified by mechanical rigidity:
1) Rigid CCL
2) Flexible CCL
Materials of CCL:
Copper Foil:
Copper foil is a cathodic electrolytic material deposited on a thin, continuous layer of metal foil on the base of the circuit board. It is easily bonded to an insulating layer, accepting a printed protective layer, and corroded to form a circuit pattern.
A prepreg (from pre-impregnated) is fibreglass impregnated with resin. The resin is pre-dried, but not hardened, so that when it is heated, it flows, sticks, and is completely immersed. Prepregs are thus fibreglass strengthened by an adhesive layer (similar to FR4 material). The name of each prepregs derives from the type of fibreglass used.
The prepreg types of different suppliers vary in thickness; in addition there are the versions "SR" Standard Resin, "MR" Medium Resin "and" HR "High Resin, depending 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. If you have any problem, please contact us---PCBWay for technical advice.
If you have any question, please contact us!
