Stacked Vias: What Does It Mean?

Stacked vias are created by stacking numerous vias on top of one another. To ensure an electrical connection, each via would be drilled first, then metalized with a small annular ring at the top and bottom. Because the annular ring is frequently extremely thin—about.002 inches—very precise registration is required. Because stacked vias may be stacked on top of one another and take up less space on a circuit board than through-hole vias, they are more flexible and practical for efficient routing of high-density boards. The efficient use of the stacked vias allows for total flexibility in the layer connection.  Additionally, it reduces its parasitic capacitance, which is frequently connected to vias. More steps are required throughout the PCB manufacturing process when using stacked vias to ensure a strong inter-via connection. Even at slightly higher prices, the increased routing flexibility often makes the difference between being able to route the design well and not being able to, which results in better design solutions. According to our engineering staff, using this layout strategy will become more and possibly even critical as component densities increase and the board’s surface area decreases.

 

What Advantages Do the Stacked Vias Offer?

Stacked vias are created by stacking numerous vias on top of one another. To ensure an electrical connection, each via is first drilled and then metalized while keeping a small annular ring at the top and bottom. Since the annular ring is frequently quite narrow—as thin as .002′′—very precise registration is required.

Less space

Additionally, since one via may be piled on top of the other, stacked vias take up less space on a circuit board than through-hole vias, increasing the possibility that the high-density board will become more flexible and useful.

Flexibility in layers of connectivity

The efficient use of the stacked vias allows for complete flexibility in layer connectivity. Additionally, it reduces its parasitic capacitance, which is frequently connected to vias. Further steps are required during the fabrication of PCBs with stacked vias in order to ensure a strong inter-via connection.

However, even at somewhat higher costs, greater routing flexibility often makes the difference between being able to route the design successfully and failing to do so, leading to better design solutions.

Improve density and size concerns

With today’s shrinking, high-signal transmission performance, and scalability in many applications, stacked vias are a way to further improve density and size concerns when creating printed circuit boards (PCBs), two very important factors.

When drilling requirements span multiple layers and blind vias have aspect ratios greater than 1:1, stacked vias may be the most reliable internal connection solution.

Better routing capabilities, lower parasitic capacitance

Also referred to as laminated buried and blind vias and stacked vias, many vias are formed together around a single center. Staggered vias are laminated vias that have distinct centers. Stackable vias not only increase density and save space, but they also provide better routing capabilities, lower parasitic capacitance, and greater flexibility for interior connections.

Challenges in manufacturing stacked via PCBs

The following issues should be taken seriously, even though it is challenging to identify the precise requirements that may result in failure:

Aspect Ratio

Reliability increases with smaller aspect ratios. Microvias (stacked vias) with an aspect ratio of 0.7, for example, have been shown to withstand accelerated life tests but microvias with an aspect ratio of 1 fail after a few thermal cycles.

Voiding

While voiding is associated with failure, its volume and form, as well as the stacked vias aspect ratio, have a more significant role. Consequently, it is not possible to say with certainty that voids always result in a higher failure rate.

Stacking versus scattering

 The criteria used to compare the dependability of staggered versus stacked microvias are inconsistent. Generally speaking, designers try to stagger the other micro vias in the vertical interconnect by stacking no more than two microvias vertically.

Fast, reliable stacked via PCB manufacturing services to keep your projects on schedule in the competitive UK and Europe electronics markets.