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What are the Benefits and Design Considerations of the HDI Multilayer PCB?

Today’s world has gradually experienced a huge leap thanks to HDI multilayer PCB. HDI multilayer PCB has been impacting the entire technical industry over the last few years. Compared to typical multilayer boards, the HDI multilayer boards come unique. Additionally, compared to ordinary PCBs, the HDI multilayer PCB include more interconnections.

A board having HDI has 120 to 160 pins per square inch of surface area. There are various layers of this board. The primary subject of this essay is HDI multilayer PCB.

What Does HDI Multilayer PCB Mean?

A multilayer pcb with many interconnections is called the HDI multilayer PCB. The components on this board are positioned next to one another to give it a compact appearance to the circuit board.

This board is used by various technological sectors, including the automobile and military. The HDI multilayer PCB alters the board’s overall performance and improves signal integrity.

Specially created HDI circuit boards offer a higher degree of performance as well as processing capacity inside a smaller area. Developing this board was driven forward by the desire for more potent and compact devices from sectors like telecoms.  Other significant elements, however, also had a significant role in developing the HDI multilayer PCB. The developments in IC technology are included in these factors.

These trends forced PCB makers to reevaluate the layouts and interconnect design of their boards. Additionally, HDI multilayer PCB can pack more power into a smaller space. This board’s capacity to carry out this task is based on integrating new techniques for the interconnect like the vias in the microvias and pad.

What are the Benefits of Using the HDI Multilayer PCB?


The HDI multilayer PCB provides different benefits when utilized in different applications. Let us consider some of them.

High reliability

The HDI multilayer PCB is far more dependable than a typical multilayer board. This PCB’s integration of heaped vias gives the PCBs optimal robustness and resistance. Therefore, once you decide to invest in this board, you don’t need to bother about its performance.

Reduces extra charges

You will receive a lot of value for your investment in this HDI circuit board. This HDI multilayer circuit board ensures sufficient quality and performance without charging extra. A single PCB that does everything is this. As a result, when you have the HDI board, you no longer require multiple regular circuit boards for various purposes.

Improvement in electrical performance

The spacing between components is less and there are more transistors on HDI PCBs. This could aid in enhancing electrical performance. These features also make minimal consumption possible, this helps in enhancing the signal integrity later on.

Smaller size and lighter weight

On the two sides of the board, extra components can be fixed. Additionally, this board allows for increased functionality while lowering its size and weight.

HDI Multilayer PCB Design Considerations


The HDI multilayer PCB is produced using different methods than a multilayer conventional PCB. Additionally, HDI multilayer circuit board manufacture starts with its design. As a result of the necessity of taking certain thermal, physical, and electromagnetic elements into account, this design process for the HDI multilayer PCB comes quite complicated. When planning your manufacturing, keep a few design factors in mind.

Types of Via Fill

The types of via fill will be determined by the particular application as well as PCB specifications. Use matching via fill types that suits your application at all times.

Additionally, there are various forms of via fill, including non-conductive epoxy, conductive epoxy, as well as electrochemical plating. The most popular via fill is non-conductive epoxy.

Sequential lamination

The Circuit board designer presses and heats copper to mix it with PCB cores during lamination. The quantity of heat and pressure required also depends on the board’s layers. The Circuit board designer must drill vias after the laminating phase is finished. HDI multilayer boards frequently have their vias drilled. Sequential lamination additionally avoids shifting and breakage during drilling.

Technology for laser drilling

Laser microvias are commonly needed in multilayer HDI PCB designs. Typically, laser drills are used to generate these microvias. Furthermore, these drills frequently produce around 20 microns of laser with respect to the diameter. Also, this laser has the ability to cut into metal as well as glass and this is why it usually creates holes that are extremely tiny

Impedance Control

To ensure that impedance will not really compromise signal integrity, designers of HDI multilayer PCB must keep trace width as well as dielectric layer thickness tolerances around +- 10%.

What are the Applications of the HDI Multilayer PCB?

HDI PCB Board Laminate Structure-2
HDI PCB Board Laminate Structure-2

HDI technology is essential to the majority of cutting-edge technologies. Additionally, manufacturers have been able to create smaller gadgets without sacrificing performance or durability thanks to the shrinking of electrical components. The HDI multilayer PCB is perfect for usage in a variety of applications, including:


Broadly speaking, equipment that makes it possible for communication devices and gadgets to work uses the HDI multilayer PCB. These boards come in switches, modules, semiconductors, and routers. Additionally, the HDI multilayer PCB is frequently used in digital video and audio equipment. Many personal devices for communication use these boards.

Medical equipment

For usage in cutting-edge electronics medical devices such monitoring, imaging, as well as laboratory analysis instruments, HDI PCBs are appropriate. When included in gadgets, these boards enhance their performance. Additionally, the precision of the medical testing as well as monitoring is increased with HDI multilayer PCB.

Aerospace and the automotive

Electronic producers may cram more capabilities into tiny places and gadgets thanks to HDI boards. Smaller space and lower weight are important in the aircraft and automobile industries. As a result, HDI multilayer PCBs are much favoured in different industries over regular multilayer boards. More computers and connections are used in modern vehicles.

These days’ automobiles contain a number of microprocessors. These microprocessors become essential for control, diagnostic, and safety features. Additionally, HDI multilayer PCB is necessary for various functions including rearview cameras, WiFi, as well as GPS.

Industrial Uses

Industrial machinery is much more computerized compared onto the way to the ever today. IoT devices are also frequently used in manufacturing, warehousing, and other industrial contexts. The majority of cutting-edge industrial machinery includes HDI technology. Additionally, machines are also incorporating smart sensors to gather utilization information.

Which Three Techniques Do Manufacturers Employ When Assembling HDI PCB Stackup?

HDI PCB Board Laminate Structure-Blind and Buried vias-3
HDI PCB Board Laminate Structure-Blind and Buried vias-3

Manufacturers can assemble HDI Circuit board stack-up in three different ways. Let us consider checking out what they offer  

Sequential Lamination

This is the process of sandwiching a sub-composite laminated and the dielectric between the two layers of copper. For sequential lamination, manufacturers employ buried vias, blind vias, as well as plated through vias.

Standard Lamination

Regular lamination entails producing HDI material in successive layers. The manufacturer then binds the layers together. Lamination is a technique used to stop copper from unintentionally transmitting signals. For this method, plated through-hole predominates.

Lamination buildup using micro vias

Even if micro vias are being used, the lamination process is still being done.

Features of the HDI Multilayer PCB Stackup

HDI Multilayer PCB has some special attributes. These include  Very small vias are among them. The industry refers to them as micro vias. Manufacturers use a laser to drill its micro vias, which have a 1:1 aspect ratio.

Another characteristic of HDI Multilayer PCB stack-up is buried vias. The stack up’s inner layers are joined together via its buried vias.

There are also blind vias inside this mix. They link the outer and interior layers. The connection is made using blind vias without taking up the full board. Elic, which are copper-filled, stacked micro vias that connect the PCB’s different layers, are present.

How Can I Tell If a Material Is Appropriate For Manufacturing HDI Multilayer PCB Stackup?


The entire HDI multilayer PCB process is at risk if the wrong PCB material is used. In order to obtain the right materials to suit the job, manufacturers need provide answers to some fundamental inquiries.

  • Does the material have what is needed thermally? If so, it is appropriate for the whole process.
  • Is the substrate material compatible with the dielectric? Any dielectric you choose has to be suitable with the substrate material used for the core.
  • Are micro vias very reliable?
  • This is the material’s ability to withstand thermal shock
  • Does the plated copper adhere well to the dielectric?

What Challenges Are Faced During HDI PCB Stackup?

The difficulties with the HDI Multilayer PCB stack-up are as follows.

  • Vias have a tendency to be delicate. This is due to the fact that while these may be susceptible to significant thermal stress, they are crucial materials for HDI multilayer PCB stack-up.
  • Manufacturers cannot avoid using the right materials. No room exists for material management or improvisations.
  • Plating issues Aspect ratios must be followed by manufacturers to ensure plating integrity.
  • The HDI Multilayer PCB equipment is fairly pricey.
  • When businesses utilize pre-pregs, the pre-pregs’ glasses frequently shift the laser’s direction.
  • The shift in direction causes the via holes of the laser to have poor quality with respect to its shape.


Many contemporary electronic devices have been developed with the help of the HDI multilayer PCB. It is more likely that HDI technology will be incorporated as electronic gadgets become smaller and more portable.




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