Differences Between Through-Hole Vias and Microvias
When it comes to designing a printed circuit board (PCB), there are many considerations, from the size of components to the thickness of the board itself. The ability to efficiently route conductive pathways through the various layers of the PCB is crucial to its functionality. This is where vias come in. Vias are holes drilled through the layers of the board, and they are then filled with conductive epoxy and plated with copper to establish a connection between the different layers. Depending on the diameter of the hole, it can be called a through-hole via or a microvia.
There are many advantages to using microvias instead of traditional through-hole vias. In addition to saving space on the PCB, they can also improve signal integrity and increase reliability by reducing noise and attenuation. These attributes are especially important in high-speed and RF electronics, where maintaining signal integrity is essential for proper function.
A key difference between through-hole vias and microvias is the way that they are plated. Through-hole vias typically have a relatively high aspect ratio, which makes them more susceptible to fracture, specifically in the area of the barrel. This is caused by stress buildup in this area due to the plating process, which causes the copper to curve inwards in this region. This is not the case with microvias, which are plated with a more consistent and defect-free copper layer. This reduces the amount of stress that is generated in this area, which helps to prevent the possibility of fracture.
What Are the Differences Between Through-Hole Vias and Microvias?
The smaller size of a microvia also contributes to its improved reliability. Using a laser drilling process, microvias are made with a high degree of precision, which reduces the chances of defects such as voids or short circuits. In addition, a microvia’s small size and reduced aspect ratio results in less mechanical stress, which helps to maintain the integrity of the connection.
Another advantage of microvias is that they can be fabricated in a variety of ways. They can be located in pads on the surface layer of the PCB, and they can be arranged in stacks for routing across multiple layers. The in-pad microvia configuration is commonly used on boards that carry fine-pitch ball grid array (BGA) components. This configuration allows the solder balls to be placed at a much closer distance, which reduces the risk of signal degradation that can occur if the components are too far apart.
Lastly, the use of microvias can make a PCB more efficient by allowing designers to skip over unnecessary layers. This is particularly helpful in creating a PCB for mobile devices where space is limited. For example, a thumb-sized PCB will not have enough room for a large through-hole component but could benefit from the power and data transmission capabilities offered by blind or buried microvias.
As the demand for PCBs that can support high-speed and high-density applications continues to rise, manufacturers are turning to microvias to provide a reliable connection between electronic components. To ensure that the resulting product performs as intended, it’s vital to work with a professional PCB fabricator who can offer a wide range of fabrication services and deliver boards that meet IPC standards.