November 15, 2018
Multilayer boards are fabricated by stacking two or more circuits over each other and establishing a reliable set of predetermined interconnections between them. The art begins with a departure from conventional processing in which all layers are perforated and plated prior to being laminated together. The two innermost layers will comprise conventional two-sided PCBs, while the various outer layers will be fabricated as separate single-sided PCBs.
Prior to lamination, the inner layer plates will be perforated, plated, painted, developed and etched. The perforated outer layers, which are signal layers, are coated such that uniform copper donuts are formed at the underside edges of the through holes. This is followed by laminating the various layers into a composite multilayer with wave solderable interconnects. The lamination can be carried out in a hydraulic press or in an overpressure chamber.
In the case of the hydraulic press, the prepared material is placed in the cold or preheated press. The glass transition temperature is the temperature at which the amorphous polymers (resins) or the amorphous regions of a partially crystalline polymer change from a hard and relatively brittle state into a viscous, rubbery state. Multilayer plates find applications in professional electronic equipment, especially when weight and volume are the main considerations. There are many PCB assembly manufacturer which you can find for multilayer PCB manufacturing process for your next project.
However, there has to be a trade-off that is simply the cost of space and weight versus council costs. They are also very useful in high-speed circuits because more than two planes are available to the PCB desinger for conducting conductors and supplying large areas of ground and supply.