Blind Vias
In the PCB manufacturing world, vias are a key way to connect layers and conductors. They can be either through-hole or blind. The selection of the type of via depends on several factors, including the location of the vias in a circuit board, and whether or not they are required to carry high-speed signals. Choosing the right type of vias for your circuit board is an important step in ensuring the reliability of your finished product.
Blind and buried vias can also create additional points of contact between the layers of your printed circuit board, which can reduce signal interference between components on the surface of the board. They can also help to reduce overall size and cost by decreasing the number of through-hole vias that are needed to reach inner layers.
However, these blind vias can pose some challenges. In particular, they are prone to thermal cycling failure and can be susceptible to fatigue cracking over time. This is a result of thermal stress being transferred through the holes in the substrate material and then back up to the component connections on the board. This can lead to cracks in the metal that form the vias, causing them to fail prematurely.
Blind Vias – Are They Prone to Reliability Issues During Thermal Cycling?
In order to avoid this, it is essential to plan for thermal relief and a balanced distribution of vias in your circuit board design. You should also consider the impact of drilled hole size and aspect ratio on heat dissipation. In addition, you should plan for proper soldering alignment over the vias to avoid connection issues during assembly.
Another common issue with blind vias is the potential for oxidation and cracking in the laminate material that they are plated in. This can occur due to poor chemistry, improper stack-up configuration, or simply aging of the laminate material. The impact of this on the performance and reliability of your PCB cannot be overstated.
The most reliable way to avoid these problems is to choose a PCB manufacturer that offers advanced manufacturing processes such as photo-defined and HDI. These processes use an extremely thin piece of laminate that undergoes all of the production steps that would be used to manufacture a 2 sided PCB, including drilling, etching and plating, before being laminated with the rest of your circuit board. This ensures that all the vias in your board are manufactured and plated to the highest possible standards.
Using blind and buried vias in your printed circuit board design can be a good choice, but it is crucial to understand their limitations and the effects that they can have on the quality of your final product. When used correctly, they can reduce the number of through-hole vias in your circuit board and increase its reliability and functionality. To learn more about creating and using these features in your PCB design, contact an expert at Altium or check out our comprehensive guide to vias. This will give you the knowledge you need to create the best circuit boards for your needs.