Stacked Microvias in HDI Printed Circuit Boards

HDI Printed Circuit Boards

The use of finer track structures, Microvias and stacked microvias is an essential part of HDI (high density interconnection) printed circuit board technology. They offer numerous advantages for both the manufacturing process and the final product, including allowing a larger number of components to be packed into the same footprint as a traditional PCB. They also enable you to reduce the thickness of the circuit board, making it more compact for your end products.

Depending on the type of hdi printed circuit board you’re looking to create, you can select different types of vias and staggered or stacked microvias. Stacked microvias are particularly useful for high-speed applications because they can carry more signals with less loss and improve signal integrity.

In addition, stacked microvias can be used to connect layers of the circuit board, as well as to save space by placing them directly in the pads of surface mount devices (SMTs). In these instances, they are referred to as “microvia-in-pad.”

Stacked Microvias in HDI Printed Circuit Boards

These types of vias are a key element of any HDI circuit board design, and they provide several advantages over standard through-holes. For one, they can be plated with pure copper, rather than the typical conformal plating process that can cause voiding and other issues. In addition, microvias can be designed to accommodate varying copper thicknesses. This is important because varying copper thicknesses allow for higher levels of reliability for different parts and conditions.

Stacked microvias can also help to reduce the number of layers needed for your circuit board, saving you money and improving manufacturability. As a result, they can be more cost-effective than standard through-holes, especially in the case of HDI boards with multiple layers and a large number of microvias.

However, there are certain limitations to using stacked microvias that should be taken into consideration when designing your board. First, it’s important to know that they can be prone to failure when there is a mismatch between the CTE of the dielectric and the copper. This can be due to stress caused by thermal cycling or mechanical shock. Failure modes include interfacial separation between the base of the microvia and the target pad, barrel cracks, and corner/knee cracks.

The good news is that this problem can be minimized by careful selection of the microvia size and by avoiding overly-large diameters. In addition, it’s crucial to use a reliable fabrication supplier who can ensure proper copper deposition and plating techniques.

At Multi-CB, we utilize state-of-the-art production equipment and 25 years of experience in PCB design to deliver process-reliable HDI solutions. We can offer a wide variety of different designs that incorporate stacked microvias, ensuring you’ll receive a high-quality HDI board that meets your requirements. To get started, contact us and request a quote today! Our dedicated account managers are ready to answer any questions you may have. We look forward to working with you!

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