Comprehensive Guide to Understand the HDI PCB

Printed circuit boards are popular in almost all industries. Especially when it comes to electronics, the use of PCB is an eminent one. However, as time passes, new and improved PCBs are gaining popularity.


If you are inclined to look at the different kinds of PCBs and have heard about the HDI PCB, then you are at the right place. Here you will learn many things about this type of PCB, and you might also get a hold on the right HDI PCB manufacturer.


Let's read this article below and understand what an HDI PCB board is and the different HDI PCB types.


What is the function of HDI PCB?

HDI stands for High-Density Interconnect (HDI) Printed Circuit Boards. Hence, HDI PCB is a form of PCB that offers a higher circuitry density than traditional PCBs. Since this density of circuitry is higher in the HDI PCB, there are vias in smaller sizes and even capture pads in the HDI PCB design.



The HDI PCBs have the smallest size of vias, might be as small as 0.006 in diameter, and contain buried and blind vias too.


This HDI technology is so innovative that it allows PCB designers to add components on two sides rather than just one. The traditional PCB used to have one side with components, but since there is a technology of buried and blind vias, the components can be placed on both sides and even closer to each other.


This absolute layout of the HDI PCB causes an increase in signal transmission and even helps avoid the loss of signals.  


Considering the types of the HDI PCB stack-up, there are three types, and every type follows a different layout and design. These kinds usually have the following stack-up packages:


  • The first one comprises vias that are either laminated or have been subjected to plating with the help of holes.
  • In another type, the PCB has vias that are either blind or buried and consist of sequential lamination.
  • The last layout will have microvias which are laminated with the buildup.


These are just how the HDI PCB might be designed. However, the three different types of HDI PCBs might comprise the following:


HDI PCB Type 1

The first type of HDI PCB stack-up comprises a design with lamination on the core. This kind of PCB has one layer of vias. These are micro-vias and might be either on one of the sides or both depending upon the application and manufacturer's choice.


The type 1 HDI PCB has no buried vias but may have blind vias or plated through hole vias. However, using this kind of PCB comes with certain limitations.


The ratio between the holes' length and diameters must be maintained by being less than 10. Secondly, the FR-4 dielectric must be thin and capable of being delaminated when higher temperatures for soldering are used. Also, the soldering should be lead-free in this HDI PCB type.


This type of HDI PCB stack-up might not suit areas where large laminated boards followed by several pin counts are chosen for use. So, it goes well with the smaller boards and limited pin counts.


HDI PCB Type 2

In the HDI type 2, the design of the PCB comprises micro-vias. These microvias can be either blind or buried, and that too over a laminated board. The micro-vias can be either on one side of the board or on both sides.


The type 2 HDI PCB is better than the type 1 because the boards could be significant and dense enough to cater to multiple components with a fine pitch. However, the count of laminated layers of the core is limited in this type, the same as type 1.


When choosing the type 2 HDI PCB, the micro-vias are present on the outer layers; therefore, these layers cannot be used as a power junction. Hence, when a single-layer stack is needed, this kind of HDI PCB might not be a suitable choice.


HDI PCB Type 3

In type 3 of HDI PCB, there are two layers consisting of micro-vias on either or both sides. The type 3 HDI PCB proves to be the best option when looking forward to the stack-up configuration.


However, these are also suitable for multiple pitch components and offer adjustability when a giant board is needed. If the plated through holes have opted, this type is subjected to the same limitations in types 1 and 2.


The micro-vias in this kind of PCB lie on the inner side; hence, the power junction could have the outer area.


Advantages of HDI PCB

There are many advantages associated with an HDI PCB, and some of them might comprise the following:


Multiple Components Placement

HDI PCB allows both layers of the board to be used; hence, when choosing HDI PCB, the multiple components can be adjusted on both sides with no limitations.


Reduced Power Usage

In an HDI PCB, the power usage is reduced to its maximum; hence this also leads to improved battery life and durable use of the product in which this PCB is installed.


Control on Heat Transfer

Due to the reduction in distance between the components in an HDI PCB, the transfer of heat is less. Therefore there is less chance for the heat to move and leave the PCB. Consequently, the stress on the HDI PCB because of the heat is also less, leading to increased life of the HDI PCB.


Efficient Connectivity

The vias on the PCB can facilitate the connectivity between different components if they are provided with materials that are either conductive or non-conductive. This leads to better transmission and improved signal strength.


Saves Space on the Circuit Board

The HDI PCBs are always suitable for space-saving on the circuit board. The layers can be increased or decreased according to the requirement. Also, it can create many smaller versions of vias compared to the larger ones.


HDI PCB Manufacturer

HDI PCB is very beneficial and comprises outstanding features that make everything relatively easier for manufacturers. However, as much as it is essential to choose the right PCB for the appliance, you must select the right manufacturer.


Elecrow offers high-quality and efficiently performing HDI PCBs that are with the investment. You will get your hands on the HDI circuit boards manufactured after thorough research and development by the team of our experts and, on top of it, a consistent after-sales service. So, get in touch with us to have your HDI PCBs ordered in bulk.


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