Materials used in PCB
Circuit Board Components – Top Manufacturing Trends
Circuit Board Components – Top Manufacturing Trends are Apart from the advancement and specific applications, there are four main materials that are guaranteed use in a printed circuit board designer and printed circuit board fabrication. Other materials are used for example Cold and Hot Temperature Conditions, Varying Thermal and Mechanical Loads and etc. The four main materials are: Laminates, Copper-clad Laminates, Resin impregnated B-stage cloth and Copper foil. Let us discuss each of the material very briefly.
Laminates are formed from the layers of cloth or paper by curing it under pressure and temperature with the thermo set resin until it becomes a standard uniform thick. They can be relatively large in size. The percentage of cloth or paper layers and thermo set resin depends on the final properties of the DI-electric.
The characteristics of the laminate are decided by the fiber (cloth) to resin ratio. Some of the characteristics are; fire retardant, DI-electric constant, loss factor, tensile and shear strength and many others.
It also decides the designation of the Laminate. The most common designation used in the lamination is FR-4, which is nothing but a board with copper over it. It is also called Copper-clad Laminates.
Some of the common substrates are:
FR-2: – Flame Resistant 2:-
They are used in economical or low application printed circuit boards. They are made up of Phenolic paper with a Phenol Formaldehyde resin.
They are used in the applications where lighter and good di electric properties are needed. They are also used where cooling power switching is required.
FR-4: – (Flame Resistant 4):-
A woven fiberglass cloth impregnated with an epoxy resin. The main properties include the low water absorption (up to about 0.15%), good insulation properties, and good arc resistance. Well-proven, properties well understood by manufacturers. Moreover; it is very common, workhorse of the industry. Several grades with somewhat different properties are available. Typical work range is rated to 130 °C.