Double-Side Buried Blind VIA Pcb

What is the purpose of PCB via?

In custom pcb fabrication:
1). What is the function and principle of adding a ground via hole near the via hole of the trace?
The via holes of the pcb board can be classified into the following types according to their functions:
1. Signal vias of high frequency mixing pressure plate (via structure requirements have the least impact on the signal)
2. Power and ground vias of industrial control PCB (via structure requires the smallest distributed inductance of vias)
3. Metal Core PCB (MCPCB) heat dissipation vias (the via structure requires the minimum thermal resistance of the via)
The vias mentioned above belong to the grounding type vias. The effect of adding a grounding Via hole near the via hole of the trace is to provide the shortest return path for the signal. Note: The via hole where the signal changes layer is a discontinuity point of impedance, and the return path of the signal will be disconnected from here. In order to reduce the area surrounded by the return path of the signal, some ground must be laid around the signal via hole. Vias provide the shortest signal return path and reduce signal EMI radiation. This radiation increases significantly with the increase of the signal frequency.
There is a saying: drilling more ground holes will destroy the continuity and integrity of the formation. The effect is counterproductive
First of all, if more holes are punched, the continuity and integrity of the power supply layer and the ground layer will be caused. This situation should be resolutely avoided. These vias will affect the power integrity, leading to signal integrity problems, which is very harmful. Holes in the ground usually occur in the following three situations:
1. Metal Core PCB (MCPCB) is used for ground hole heat dissipation;
2. BVH (buried/blind via hole) PCB is a ground hole used to connect the ground layer of a multilayer board;
3. The Microwave radio frequency board is the location of the via hole used for layer change of high-speed signals.
3). But all these situations should be carried out while ensuring the integrity of the industrial control PCB.