Multi-Layer PCB refer to printed circuit board has more than two copper layers, such as 4L, 6L, 8L, 10L, 12L, etc. As technology improving, people can put more and more copper layers on the same board. Currently, we can produce 20L-32L FR4 PCB.
By this structure, engineer can put trace on different layers for different purpose, such as layers for power, for signal transfering, for EMI shielding, for components assembly, and so on. In order to avoid too many layers, Buried Via or Blind via will be designed in multi-layer PCB. For board more than 8 layers, high Tg FR4 material will be popular than normal Tg FR4.
More layers it is, more complex & difficult the manufacturing will be, and more expensive the cost will be. The lead time of multi-layer PCB is different from normal one, please contact us for a exact lead time.
Top silkscreen/Legend: to identify name of each PAD, board part number, data, etc;
Top Surface finishing: to protect exposed copper from oxidation ;
Top Soldermask (overlay): to protect copper from oxidation, to be not soldered during SMT process;
Top Trace: copper etched according to design to carry on different function
Substrate/Core material: Non-conductive such as FR4, FR5
Middle Layers, such as GND, VCC, Inner 3, Inner 4, etc.
Bottom trace (if any): (same as above mentioned)
Bottom soldermask (overlay):(same as above mentioned)
Bottom surface finishing: (same as above mentioned)
Bottom silkscreen/legend: (same as above mentioned)