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What are the common PCB problems and how to prevent them?
For 5G applications, the risk of system failure increases if the PCB is not operational. PCBs can fail if they face the following challenges:l Signal Integrity: As 4G devices, most 5G devices will require High Density Interconnect (HDI) with thinner traces. These thinner traces are used because they help reduce device size and are also great for input/output signals. However, these thinner wires can cause signal integrity issues in 5G devices. If there are small changes in the physical properties of these lines, they can delay the signal by a few microseconds, which can suffer in the long run.
l Abnormal impedance: Strict impedance is one of the important requirements for high-frequency signals. In HDI, impedance can be affected by wire cross-section, shape, size, space/line width, and a few other factors. Additionally, cross-sections created using subtractive etching may produce multiple impedance anomalies. To solve this problem, today, PCB manufacturers are adopting an improved semi-additive process (mSAP), which helps ensure the accuracy of the traces. These traces can also be designed with straight walls to ensure better impedance control.
Different technologies employed by PCB manufacturers to become 5G-ready
The following technologies are helping PCB manufacturers prepare for the future for 5G applications.
l Improved semi-additive process: This allows 5G equipment manufacturers to achieve high density without worrying about signal degradation. During this process, the laminate is covered with a thin layer of copper. As an additive process, this copper lamination is performed in areas without resist. The copper found between the conductors is then etched away. Unlike earlier subtractive processes, the geometry of the etch can be better defined in this process. This definition can be performed using photolithography, which helps ensure greater accuracy and minimal signal loss.
l Advanced Automated Optical Inspection (AOI): AOIs are not new, they have been used for a long time to identify defects in PCB manufacturing. These systems are primarily used to check CAM designs and make sure the product matches the original design. Is that all there is to 5G PCB? no. These PCBs require an AOI system with additional functionality. This is why there are now advanced AOI systems that can easily identify potential defects in PCBs. For example, they can identify defects at the top and bottom of the wire. Advances in AOI technology will allow PCB manufacturers to combine different manufacturing processes on a single platform and identify potential defects prior to mass production. Until a few years ago, they used different tools to identify various defects. This integrated AOI system will allow them to save the floor space and money required to identify major and minor design flaws. Additionally, an integrated AOI system will help them make better decisions by providing usable data at their fingertips.
5G technology is still in its infancy, and large-scale implementation will take time, and PCB manufacturers are still preparing for the dramatic changes that are coming.
