PCB multilayer

Multilayer PCB is a printed circuit board that has more than two layers.
Unlike a double-sided PCB that has only two conductive layers of material, all multilayer PCBs must have at least three layers of conductive material enclosed in the center of the material.

How are multilayer PCBs made?

To produce multilayer PCB alternating layers of Prepeg and base materials are laminated together at high temperature and pressure. This process ensures that the air does not get trapped between the layers, that the conductors are completely encapsulated by the resin and that the adhesive that holds the layers together is properly melted and polymerized. The range of material combinations is wide, from simple epoxy glass to ceramic or Teflon materials.
The alternating layers are then inserted into a rolling press. To this “stacking” apply extremely high temperatures and pressures, which cause the Prepeg to “merge” and join the layers together. After cooling, the final result is a very hard and solid multilayer board.

Advantages of multilayer PCBs (compared to single or double PCBs)

• Higher assembly density
• Small size (significant space savings)
• Greater flexibility • Built-in controlled impedance characteristics
• EMI shielding thanks to the accurate positioning of the power and ground layers.
• Reduces the need for interconnection cabling (reduces overall weight)

Multilayer PCB applications

While the advantages in terms of weight and space of multilayer PCBs are particularly valuable for aerospace PCBs, there are many fields of use for multilayer PCBs:
• Computer
• Data store
• Signal transmission
• Cell transmission
• Repeaters of mobile phones
• GPS technology
• Industrial controls
• Satellite systems
• Handheld devices
• Test equipment
• X-ray equipment.
• Cardiac monitors
• Atomic accelerators
• Centralized fire alarm systems
• Fiber-optic receptors
• Nuclear detection systems