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Micro via in high-density interconnector (HDI) PCB

Micro via in high-density interconnector (HDI) PCB


In this article, you will learn about micro vias in PCBs. Micro vias are small holes in a printed circuit board (PCB) that are used to interconnect layers. They are often used in high density interconnector –HDI PCB designs to reduce the amount of space needed for vias, increase the number of interconnections per board, and provide improved electrical performance. Micro vias are typically created using a laser drilling process that creates small, precise holes in the board substrate.

What is micro via in PCB?

What is micro via in PCB?

“Micro vias” are so-called because of the microscopic size of the connections that they create between layers of printed circuit boards. Printed circuit boards rely on these minuscule vias to build a conduit for electricity and signals to move through their numerous layers. This is necessary for the boards to function properly. Micro vias are fast turning into an essential component of printed circuit board (PCB) creation because of the increased productivity, durability, and dependability that they give.

Because micro vias enable designers to create complex routes in considerably smaller regions than with conventional through-hole vias, they play a significant contribution in the total reduction in size of a printed circuit board. They are also much more cost effective than the conventional through-hole vias, making them attractive for businesses and manufacturers that want to reduce the costs of their PCBs.

What are the types of micro via?

There are two distinct styles of micro vias, known as staggered and stacked. Micro vias that are near to one another can either be “stacked,” in which case they will share a common connection on the same layer, or “staggered,” in which case they will share connections but will be positioned on different layers.

It is less expensive to implement stacked micro vias than it is to construct staggered micro vias because stacked micro vias only require one layer of routing and a portion of the computing power that staggered micro vias require. Electrical and thermal crosstalk is more likely to take place in stacked micro vias due to the near proximity of many vias that are routed on the same layer.

Why use Micro vias?

Why use Micro vias?

Because of their potential to boost component density on a PCB without considerably expanding its footprint, micro vias are increasingly being used as the standard. There are a number of benefits to this higher density, including smaller electrical components that are simpler to install and fewer layers required to finish a PCB.

Micro vias improve electrical communication between PCB layers and cut down on the amount of signal traces required for sophisticated circuitry, both of which result in cost savings. Given these advantages, micro vias find widespread application in fields ranging from medicine and consumer electronics to aerospace and defence.

What is the size of micro via?

Micro vias are small plated through-holes that are typically less than 0.006 inches (150 μm) in diameter, and between 0.004 and 0.008 inches (100 to 200 μm) in depth.

How is micro via made?

To create the tiny holes known as micro vias, either pure copper or a plating material made of epoxy and copper resin is utilised. For the typical method, the micro via is first partially filled with copper through a process called conformal plating, and then the rest of the space is filled with copper by a process called pulsed plating. When this is done, the microvias are ready for use after the extra copper has been removed, either chemically or mechanically. Micro vias are plated with epoxy and copper resin for improved surface polish, lower porosity, and stronger adherence to the circuit board during manufacture.

What is the difference between micro via and blind via?

What is the difference between micro via and blind via?

There are many differences between micro vias and blind vias.

1.Micro vias can be seen from both sides of the PCB but the blind vias can be seen only from the component side.

2.When compared to micro vias, which must be drilled from both sides of a PCB, blind vias are often deeper and are drilled from the outer layer.

3.When it comes to linking PCB layers, micro vias can span multiple layers but blind vias can only link two.

4.Because of the additional time and effort involved in PCB drilling, micro vias are also more expensive than blind vias. However, micro vias are becoming increasingly prevalent in high-performance PCBs due to their capacity to generate connections between numerous layers, which blind vias cannot.

What is a stacked micro via?

A stacked micro via is a sort of printed circuit board design that involves connecting many circuit layers by means of vias. Because it enables a greater degree of intricacy and efficiency than conventional single-layer circuit boards, stacked micro via technology is becoming an increasingly popular choice for the design of modern printed circuit boards (PCBs).

This is due to the fact that the design of stacked micro vias enables the connectivity of many layers of circuits, which results in an increase in the total number of connections that are available. Because of this, it is possible to create more intricate designs and make better use of the available space on the board, which is useful to both the designers and the consumers.

What is aspect ratio of micro via?

What is aspect ratio of micro via?
On a printed circuit board, a micro via is a very small hole that has an aspect ratio of 1:1, which indicates that its height and width are of equal dimensions. In spite of the fact that a micro via’s height and width both contribute to the same aspect ratio, a micro via’s size is typically significantly more compact than that of other types of vias. This has the advantage of providing a larger density of interconnections on the printed circuit board, which ultimately results in the board functioning at a better level of efficiency.

How to calculate the aspect ratio of micro via?

The diameter of the hole and the depth of the micro via are needed to compute the aspect ratio. How to do this is to first measure the hole’s diameter with a microscope and then measure its depth with a different tool. The ratio of these two dimensions is the aspect ratio.

How much current can a micro via carry?

How much current can a micro via carry?
Depending on their size and design, micro vias can withstand currents of a few milliamperes to several amperes. The micro via’s current-carrying capacity is proportional to its size; larger micro vias may carry more current than smaller micro vias. The micro via’s current carrying capacity will also depend on the material used in its construction and the details of its design.


We hope that after reading this article, you should have a comprehensive knowledge of micro vias, their importance and their benefits. Through understanding micro vias, you can develop a greater appreciation for their purpose and importance in the development of modern technology. For more information regarding other electronic components and devices, PCB, and PCBA, please visit our blog on IBE.



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