All You Need to Know About HDI PCB

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Electronics are continuously advancing, and devices are becoming more powerful with every new generation. At the same time, the hardware is getting smaller while improving its performance and power efficiency. One of the biggest reasons we have been able to achieve high performance within compact size is because of the HDI PCB. This article covers all you need to know about HDI PCB.

What is an HDI PCB, and what's the difference from the standard PCBs

HDI PCB is the abbreviation of "high-density interconnected printed circuit board". It is an interconnection of several circuits together. Due to this, the HDI PCB does not need a large surface compared to a standard PCB.

When characterizing an HDI PCB, you can characterize it by close spaces between components, thin lines, and tighter wiring, which provides better heat dissipation, faster connection, and high performance.

HDI PCB vs. Standard PCB.

When comparing their technicalities with the standard PCBs, you will find that HDI PCBs provide better signal integrity and have a higher density, resulting in thin and compact products. HDI PCBs have a higher layer than regular PCBs, and their production is done on the micro level.


These are made with micro laser vias while the standard PCBs use mechanical drilling, so achieving the same accuracy is impossible with the standard PCB.

Ball grade Arrays

In terms of technical application, ball-grade arrays make an important part of most PCBs today and they are needed when one IC has several pins under a small surface area. It is only possible with HDI PCB because a micro via-in pad is only available in these PCBs.

HDI PCB design process overview.

Designing HDI PCB involves several steps, and most of those steps are not involved in manufacturing standard PCBs. The main steps involved in designing an HDI PCB include:

  • The process starts with determining the inner and outer layer count of the HDI PCB used for routing all the signal layers. It is done by utilizing the interface counter and direction regarding the largest IC or the BGA on the board.
  • Next, the fabrication house gets you all the dielectric information so you may choose the right materials to make your HDI PCB stack-up structure.
  • According to the count of layers in your HDI PCB and the overall thickness, you must decide which routing style you will use to route the signals through your inner layers. It is an important part of the planning and manufacturing process to yield maximum efficiency and performance from the HDI PCB.
  • Now you will conduct the reliability assessment for your HDI PCB to ensure that all the material and design elements work as intended under the stress of the HDI structure during the assembly, production, and operation phases.
  • You may choose a fabricator and according to their capabilities, you will determine your design rules. Following these rules, you will create a more reliable design in manufacturing and operation.

As your design is complete, you can leave the rest to the fabricator.

Some challenges to overcome while HDI PCB design

Most part about the success of HDI PCB comes from their efficient design. During the design process of these high-density interconnected PCBs, you may come across several challenges, including the following:

  • As the design process starts, you must manage the surface area on both sides of the PCB to ensure that all the components easily fit. It is because the layers stack up, and the number of components on either side becomes massive.
  • Usually, labs and workplaces lack the tools and working areas for HDI PCB. So, the lack of resources can be a significant issue you may have to deal with.
  • The components you use on these PCBs must be available in smaller sizes. It is a huge challenge as all components are not available in compact sizes with the same result.
  • As you design the layered PCB layout, you have to trace numerous routes for different layers of the overall HDI PCB design.
  • You must keep the trace routes as short as possible because the longer ones may increase the signal flight times, resulting in a lack of performance.

So, for an efficient HDI PCB design process, you need the right planning and compact components, and a workplace with all the resources is also necessary. Otherwise, one problem while designing HDI PCB will lead to another, and this process will be no less than a hassle.

Top applications of the HDI PCB

HDI PCB is used in almost every aspect of life today. Here are the top applications of HDI PCB:

Smartphones and tablets

Everyone has a smartphone, and the technology inside these compact devices relies only on the HDI PCB. Due to compactness and higher performance capabilities, we today have whole computers within the palm of our hand.


Vehicles are becoming smarter with self-driving and other intelligent features. It has been possible because we can fit smart computers inside vehicles. With HDI PCB, these compact circuits can save a lot of space inside vehicles. With the combination of smart circuits with high-end automotive hardware, the automotive industry is evolving quickly.


HDI PCB is responsible for the rapid advancement in the healthcare field. With smaller circuit boards, medical devices are becoming more compact, so they become easy to carry and offer higher efficiency as well. The smaller components also fit easily in all equipment, thus resulting in providing:

  • Better diagnostic facilities
  • Better health monitoring
  • Improved life support
  • More effective treatment with small cameras going inside the body

Wearable tech

Wearable technology has become better than ever. Smartwatches today can detect and predict if you will have a heart attack or other health issues. However, wearable tech is not only limited to smartwatches.

The VR technology has improved a lot, and so have the hearing accessories, including the TWS technology and ANC. These products are becoming compact yet deliver outstanding functionalities with a premium experience.

Military and aerospace

The communication sector in the military and aerospace industries incorporates HDI PCB in all their devices and other equipment, making them smart and more capable. Thus, this technology helps improve defense, and the forces are always ready to deal with hazardous conditions. With resistance to external factors, the HDI PCB technology makes a perfect choice for these applications.

Benefits of HDI PCBs

This wide range of applications of HDI PCB and high demand is only because of the significant benefits these bring over traditional PCBs. Below are the details of the top 6 benefits of HDI PCB.

Tighter design and compactness

HDI PCB is high-density in nature, making it way smaller. It comes with blind vias feature that cuts down the overall space required to link different PCB layers, making the overall construction very compact. The circuit boards thus become way small and versatile.

Lightweight materials

HDI PCB is better than standard PCB in the choice of materials. Toe traditional PCB uses aluminum, copper, and fiberglass as main materials with several others making the final product bulky. On the other hand, HDI PCB is made with a careful selection of materials in the right amounts to keep the bulkiness away while also keeping the PCB lightweight and well-performing.

Higher reliability

HDI PCB offers higher reliability because it is designed in a stacked-up via, which makes the connections and traces far from being compromised. It protects connections and traces from environmental factors resulting in better reliability than standard PCBs, where everything is exposed to the environment where the traces and connections are unreliable.

Sharp signal integrity

One of the biggest benefits of going for the HDI PCB is that the signals don’t have to travel long distances. The compact PCB size keeps traveling distance less for the signals offering sharper signal integrity. It creates a clear difference between traditional PCBs and HDI PCBs in terms of performance.

Better thermal management

Thermal management is a huge concern with compact items because they are not good at dissipating heat. However, the HDI PCBs are better in thermal management as the distance for heat to travel and escape the structure is way less. With better thermal management, the HDI PCB extends its life because the components or the PCB as a whole do not bear much heat wear and tear.

Conductivity management

Although it is highly reliant on the PCB design, when the HDI PCB is designed well, the laser-drilled vias promote transmission work between component leads among all the conductive and non-conductive materials. With better design, the components come closer, so the transmission range lessens, reducing delays and increasing signal strength.

Final words

PCBs have revolutionized our electronic industry; today, we are surrounded by thousands of PCBs everywhere. As these have revolutionized electronics, PCBs have gone through a lot of advancements and one of the best examples is the HDI PCB. These PCBs come with amazing functionalities and reliably while offering signal integrity like never before for accurate results.


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