Back drill PCB

Basic parameters (Customizable):

What is Backdrill PCB？

Back drilling is actually a special kind of depth drilling, the role of back drilling is to drill out the plated through hole segment that does not play any connection or transmission role, to avoid causing reflection, scattering, delay, etc., to bring “distortion” to the signal, while reducing the wiring layer, it is also an important research direction for the light, thin, small improvement and upgrading of the circuit board.

With the popularization of the fifth generation mobile network and the improvement of signal transmission frequency, the problem of signal integrity in PCB has received more and more attention. In PCB design, the plated through hole is a bridge connecting the lines of the various layers, but in practical applications, not all layers need to be interconnected, if the conventional plated through hole is not processed, the signal will be transmitted on the excess copper column, which is often called the stub. In a high-frequency signal, the stub greatly affects the signal.

At present, the industry mainly use back drilling to solve this problem. Back drilling refers to the process of a second drilling after the through hole is completed to remove excess stubs. Backdrilling has been widely recognized as a simple and effective method to minimize the signal attenuation of through hole pairs. Back drilling is also known as depth drilling, using CNC drilling equipment, by removing the hole Stub.

The diameter of the drill bit used in back drilling is generally 8mil larger than the through hole to remove unwanted conductor residue. To ensure that the back drilling does not penetrate the nearby tracks and planes, the spacing between the tracks and planes near the holes and the corresponding layers of the back drilling holes should be at least 10mil.

Features:

1.Backdrilling helps reduce signal attenuation and ensures a stronger and more reliable signal. In addition, this technique helps minimize the impact of stubs on impedance matching, thereby reducing EMI/EMC radiation.

2.Back drilling is also an effective way to prevent signal distortion problems. It is well known that through-hole stubs cause deterministic jitter, which can be caused by signal crosstalk, EMI, and noise. By removing these stubs, backdrilling can help eliminate sources of deterministic jitter, improve signal quality and prevent signal distortion problems.

3.The back drilling helps to minimize crosstalk between the plated through holes, reduce the excitation of resonance mode, and expand the channel bandwidth.

4.Minimize the use of buried and blind holes with minimal impact on design and layout to simplify PCB production and reduce costs.

Applications：

Backplanes are mainly used in communication equipment, large servers, medical electronics, military, aerospace and other fields.