Want to do a good job of high-complex PCB First, do the DFM of these High frequency PCBs from the engineering design; Second, for these PCBs ，you need to choose suppliers with particularly strong engineering capabilities.

We need to pay special attention to suppliers, materials, design, etc. when doing high-complexity PCB DFM. For example, in PCB design, the more layers, the layer alignment accuracy will decrease. Therefore, when considering the aperture be especially careful with the distance from the hole to the line. Similarly, the holes width of the vias should also be increased, because the alignment is not accurate, and the disk may be broken when drilling. Therefore, when we design a board with a large number of layers, we must appropriately increase the diameter of the inner orifice disk. In addition, when considering the distance from the hole wall to the trace, we must pay special attention to the shrinkage of the high Tg board under thermal shock conditions.

When designing high-complexity PCBs, you must be careful about surface treatment. Judging from the situation we currently use, hot air leveling is not suitable for high-rise, large-size and high-complexity boards. For ENIG, due to some fine-pitch and dense-pitch devices on high-complexity boards, the size of the pads is very small, which will greatly increase the sensitivity to black disks. Therefore, we are basically on high-complexity boards.

The use of ENIG surface treatment is prohibited. For OSP, it is necessary to consider its adaptability to ICT testing.