Multi Layer PCBs
Multilayer PCB is a type of circuit board that has more than two layers.
Unlike a Double-Sided PCB which only has two conductive layers of material, all multilayer PCBs must have at least three layers of conductive material which are buried in the center of the material.
Alternating layers of prepreg and core materials are laminated together under high temperature and pressure to produce Multilayer PCBs. This process ensures that air isn’t trapped between layers, conductors are completely encapsulated by resin, and the adhesive that holds the layers together are properly melted and cured. The range of material combinations is extensive from basic epoxy glass to exotic ceramic or Teflon materials.
Following are some benefits of Multilayer PCBs (compared to single or double-sided PCBs).
Higher assembly density
Smaller size (considerable savings on space)
Easier incorporation-controlled impedance features.
EMI shielding through careful placement of power and ground layers.
Reduces the need for interconnection wiring harnesses (reduces overall weight)
While the weight and space benefits of multilayer PCBs are especially valuable for Aerospace PCBs, multilayer PCBs are also beneficial to applications where “cross-talk” levels are critical. These are a few other the applications using multilayer printed circuit boards:
Cell Phone Repeaters
Nuclear Detection Systems
Space Probe Equipment
NOTE: Code Red Tronics is currently reasearching to produce Multi Layer PCBs on a large scale for the first time in Lahore and maybe even Pakistan.