Why is PCB Via Fill Necessary in Circuit Board Design?
PCB Via Fill Necessary in Circuit Board Design
For a PCB to function properly, it needs to be able to conduct electricity throughout its structure. One way to do this is by connecting different layers using vias. These are holes that are filled and plated over with copper to create an electrical connection. These vias can also be filled with other materials, but copper is the most common choice as it offers superior thermal and electrical conductivity compared to other options.
When a via is filled, it is referred to as a “via plug.” There are two common types of pcb via fill: conductive and non-conductive. Conductive via fills are typically made of silver-coated copper particles in an epoxy resin. These are designed to offer excellent thermal and electrical conductivity when cured. They are often used in applications that require high current levels, such as computer servers and digital circuits.
On the other hand, non-conductive via fills are typically made of solder mask or epoxy resins that offer little to no heat dissipation or current capacity. Nonetheless, they do protect the via hole from contamination and increase the reliability of the board. In fact, they are more popular than conductive via fills for use with buried and blind vias, as well as with the emerging Via-in-Pad (VIP) process.
Why is PCB Via Fill Necessary in Circuit Board Design?
Both conductive and non-conductive via fills are required for the manufacturing of a circuit board, but the choice between them depends on several factors. First, it is important to consider the CTE match between the material of the via fill and that of the laminate around it. This is because metals tend to expand and contract at a faster rate than laminate, which can lead to stress fractures or even electrical opens in the worst case scenario.
Another factor to consider is the plating requirements. If the vias are to be plated shut with copper, it is recommended that they be filled and planarized before the plating process. This will ensure that the copper plates evenly over the entire structure and reduce the risk of voids, which can occur as a result of imbalanced leveling agents or inadequate solution agitation during the plating process.
In order to ensure that a PCB’s vias are filled correctly and efficiently, the board must be thoroughly cleaned and prepped. Once these steps are complete, the board can be ready for the via-filling process. There are several different ways to fill a via, including mechanical drilling, laser drilling, and plasma cutting. However, it is important to remember that each method has its own set of advantages and disadvantages.
To ensure that your circuit board’s vias are properly filled and protected, the best option is to use a professional PCB fabrication company. These companies will have a team of engineers on hand to prioritize performance, manufacturability, and cost while ensuring that the final product meets your specific requirements. They will also ensure that your project is fabricated and delivered in the shortest possible timeframe. For more information, check out our PCB design services page.