What Are Stacked Vias?

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Stacked vias are becoming increasingly common and important in printed circuit board design, so it is important to know what they are. Put simply, stacked vias is when you have multiple layers of copperor conductive material on top of each other. In order to connect these different layers of copper together, an opening is created through the layers of copper.

Stacked vias are one of the most basic yet important elements in any printed circuit board (PCB). In fact most of your boards have a few stacked vias in them. This overview shares everything there is to know about stacked vias, from the basics to an in-depth technological explanation.

Stacked Vias in PCB: An Overview

Stacked vias are a way to create a hole in the board that goes all the way down to the substrate. They can be used for a number of different purposes, but most commonly for mounting an IC or other component on the back side of the board.

In order to understand what stacked vias are, it helps to know how conventional vias work. A via is an electrical connection between two copper layers through an insulating layer (usually FR4). A typical via consists of a round hole drilled through all three layers, filled with conductive material, and plated with copper on both sides. The purpose of this is so that there is good contact between the two layers being connected.

A stacked via removes one layer from this equation by drilling a hole all the way through only two layers instead of three. This means that you can drill holes through both sides of the board without having to worry about how they will line up at multiple points on each side. This makes them ideal for mounting components on both sides of your PCB while still providing good thermal dissipation like thermal pads.

Two Types of Stacked Vias

Stacked vias come in two main types: blind and buried.

A blind via is just that — a hole drilled through an IC die to connect one layer of the PCB to another layer. The holes are typically created with a laser, but they can also be punched with a mechanical tool.

A buried via is different. It is not a hole drilled through an IC die; rather, it is a solid copper pad that connects one layer of the PCB to another layer. The pad is placed on top of the die before it is bonded to the substrate and then plated with copper after bonding.

The advantages of buried vias include better solderability and improved thermal performance, while blind vias are easier and faster to manufacture.

One important thing to keep in mind with both types of stacked via is that you need to make sure your design provides enough room for them. This means making sure there is enough space around your component leads so that they can connect with their respective via holes without interfering with other components or traces on your board.

Difference Between Stacked Vias and Traditional Single-Layer Connections – Advantages

  • The difference between stacked vias and traditional single-layer connections is that they can be used to connect multiple layers within one plane. This can be beneficial because it allows you to use one layer for both signal and power planes instead of having separate layers for each plane. This makes designing simpler since you only have one layer to work with instead of two or more layers that would otherwise be required if you were using traditional single-layer connections alone.
  • Another benefit of using stacked vias is that they allow for better signal integrity than traditional single-layer connections do by allowing signals to travel through multiple layers without having interference from other nearby traces on your board or from other parts of your circuit such as capacitors or inductors which may cause crosstalk problems with your circuits if not properly shielded.
  • Stacked vias allow for much denser packaging than conventional methods allow. This can reduce costs by reducing the number of interconnects needed to connect components on different levels in a chip stack. In addition, they allow for more efficient heat dissipation by providing more paths for heat to escape through the substrate than just one per level.
  • The use of stacked vias also reduces the risk of damage caused by electrostatic discharge (ESD). This is because ESD travels along conductive surfaces rather than through them like crosstalk does and because stacked vias provide multiple conductive surfaces between your circuit layers which provides multiple paths for ESD currents to flow between them thus preventing localized buildups of charge that could be damaging.

Stack Vias Common Applications

Stack vias can be used for:

In-Circuit Testing — During testing, a tester connects test points on one side of the board with test points on the other side through vias. The tester then connects test points on the second layer with test points on the first layer through vias as well.

I/O Interconnections — Stack vias are often used to connect pins from different surfaces on an ICs with each other or with other components on the board such as capacitors and resistors. This is done because ICs are typically manufactured using surface mount technology (SMT), which requires that traces between components be as short as possible so that they do not interfere with each other's operation during testing.

High-Speed Data Transmission — Stack via holes can also be used for high speed signals that need to travel between layers at high speeds. For example, in an application where two layers are stacked together, stack vias can be placed strategically so that signals can pass through both layers quickly without having to go around corners or make long detours through the substrate below them.

Summing Up

The bottom line is that if you are a beginner in PCB design, it is recommended that you fully understand the concept of via stacks and how they can affect your own designs before creating a complex PCB. They represent a coders' approach to PCB design and tweaking, which often leads to updated guides for beginners on how to avoid common pitfalls in PCB trickery. This will also result in your board working the way you designed it, thus giving your customers a superior end product. To learn more about PCBs in general, visit Hemeixin.

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