PCB circuit board back drilling is a special kind of controlled depth drilling. In the production process of PCB multilayer boards, such as the production of 12-layer circuit boards, we need to connect the first layer to the 9th layer. Usually we drill through Hole (drill once), then sink the copper. In this way, the first floor is directly connected to the 12th floor. In fact, we only need the first floor to be connected to the 9th floor. Since the 10th to the 12th floor are not connected by wires, they are like a pillar. This column affects the signal path, which can cause signal integrity problems in the communication signal. So this extra pillar (called STUB in the industry) was drilled out from the reverse side (secondary drilling). So it is called back drill, but it is generally not as clean as the drill, because the subsequent process will electrolyze a little copper, and the drill tip itself is also sharp. Therefore, the circuit board manufacturer will leave a small point. The length of this left STUB is called the B value, which is generally in the range of 50-150UM.
Advantages of PCB back drilling
1. Reduce noise interference;
2. Local plate thickness becomes smaller;
3. Improve signal integrity;
4. Reduce the use of buried blind holes and reduce the difficulty of RV1126 IP Camera Module Board Sony IMX415 335 307 PCB Board production.
The role of RV1126 IP Camera Module Board Sony IMX415 335 307 PCB Board back drilling
In fact, the role of back drilling is to drill out the PCB through-hole sections that do not play any role in connection or transmission, so as to avoid reflection, scattering, delay, etc., which cause high-speed signal transmission, and bring "distortion" to the signal. Research shows that the main factors that affect the signal integrity of the signal system are design, PCB board materials, transmission lines, connectors, chip packaging and other factors, but the vias have a greater impact on signal integrity.
