elepcb.com - home logo
An Innovative Multilayer PCB Manufacturer

Custom PCB Manufacturing Service!


High-Density Interconnect Printed Circuit Board is referred to as HDI PCB. These circuit boards enable for smaller and more compact electronic devices because they have a higher component density than conventional PCBs. Several processes, including laser drilling, photolithography, and etching, are used to make HDI PCBs. The production of a substrate, which is frequently constructed of a material like fiberglass or ceramics, is the first step in the process. The substrate is next covered with a very thin layer of metal, such as copper. After that, a photoresist is used and exposed to a pattern to determine the layout of the circuit. The desired circuit patterns are then produced by etching away the exposed metal once the photoresist has been created. The circuit traces are then exposed on the substrate once the residual photoresist has been removed.

Table of Contents

1. What is a HDI PCB?

The PCB HDI definition is High-Density Interconnect Printed Circuit Board. A circuit board that has more wire per unit area than a typical board is referred to as an HDI PCB. HDI PCBs contain smaller vias, fewer capture pads, and a greater connection pad density. They also have finer gaps and lines. It aids in improving electrical performance and reducing the size and weight of the apparatus. For expensive laminated boards with a high layer count, HDI PCB is the preferable choice.

The board should have a variety of features, such as high-frequency transmission capabilities, impedance management, reduces redundant radiation, etc., in order to meet the electrical requirements of high-speed signals. The board’s density has to be increased due to the arrays and downsizing of the electronic components.

What is a HDI PCB

Due to the tiny pads and fine pitch of the circuitry on the circuit board, the positioning of the components on the board requires greater accuracy than a conventional board design. Leadless chips need unique soldering procedures as well as additional assembly and repair operations.

The HDI PCB circuitry is thinner and lighter, therefore the PCBs may fit into tighter locations and have less mass than traditional PCB designs. Even the lower size and weight indicate that there is less risk of injury from mechanical shocks.

1.1 Applications Of HDI PCB

One of the areas of the printed circuit board industry with the quickest growth is HDI PCBs. The design may use thinner lines and gaps, smaller vias and capture pads, and greater connection pad densities since HDI PCBs have a higher circuit density. HDI PCBs often have microtias with a diameter of 0.006 or less, as well as blind and buried vias.

1.1.1 Healthcare

Presently, designers of PCBs for the medical business are taking design cues from the newest advancements in HDI PCBs, particularly in terms of size. Since HDIs are compact and easily fit in implants and imaging equipment, they are being incorporated into the majority of medical devices. Smaller chips need less intervention because these devices are crucial for illness diagnosis and treatment. As an illustration, a cardiac pacemaker is an apparatus that is affixed to the human heart and keeps circadian rhythms in check. Researchers can develop more effective, more compact pacemakers thanks to smaller HDIs.

The camera used during a colonoscopy, which is used to examine someone’s colon, is another illustration.

1.1.2 Automotive Industry

Manufacturers of automobiles and other vehicles are drawn to HDI PCBs because they enable a great deal of creativity. With HDI PCBs, you may boost a vehicle’s performance while saving more room. PCBs are used by futuristic and hybrid vehicles like Tesla to power the electronic systems that prolong battery life. Thanks to HDI PCBs, other gadgets like tablets and smart assistants may also easily fit into the car’s dashboard.

1.1.3 Digital Devices

Compare modern digital gadgets like cellphones to their predecessors from 5 years ago. Both the size and weight will be noticeably different. HDI PCBs used in ELIC (Every Layer Interconnection) fabrication allowed for this transition. HDI PCBs are responsible for the creation of innovative products like smartwatches and thinner, more portable electronics. To cram the newest features into a tiny gadget, HDI PCB technology is also used in fitness bands and VR headsets.

1.1.4 Aerospace and Military

Due to HDI’s market-leading versatility, strategic equipment like missile and defense communication systems uses it. HDI PCBs meet changing requirements in the aerospace and military industries. In this business, a little PCB is present in every device to carry out some function. Other forms of communication, such as mobile phones, trackers, and cameras, are getting smaller and some have up to ten layers of HDI architecture.

So now you are aware of several key areas where HDI PCBs excel. However, while making your budget, it’s still essential to consider its prices. Some of the primary elements that affect HDI PCB’s price are listed below:

1.1.5 Number Of Layers

The pricing will vary depending on the number of layers and the kind of stickups you need. For instance, 2-n-2 HDI board layouts are more expensive than 1-n-1 versions because they are more complicated.

1.1.6 Materials

Regarding the kind of material your HDI PCB uses, you have many of options. Depending on how your board will be used, you can pick from fiberglass, metal, FR4, or other materials; your ultimate pricing will vary accordingly. Some options for surface treatments are immersion tin, immersion silver, HASL, ENIG, gold, and immersion tin. Because of its flatness and solderability, ENIG is used in the majority of HDIs.

Example of hdi multilayer pcb
HDI 8 Layers Multilayer PCB Sample
4 Layers Rigid Flex PCB Board
4 Layers Rigid Flex HDI PCB Board

2. Benefits Of Using HDI Technology PCB

Compared to alternative solutions, HDI technology offers a number of benefits that can enhance the outcomes of your project. Using HDI boards in your product may increase its overall quality and performance as well as your customer satisfaction rate and bottom line with the appropriate design and provider. Additional benefits include: 

2.1 Smaller Size and Lower Weight

The ability to secure more components on both sides of the bare PCB using HDI boards enables you to squeeze more functionality into a smaller area and increase the equipment’s overall capabilities. You may increase functionality while making your goods smaller and lighter thanks to HDI technology.

2.2 Improved Electrical Performance

An increase in the number of transistors and a reduction in the distance between components can result in better electrical performance. Lower power consumption is made possible by these qualities, which enhances signal integrity. More rapid signal transmission rates and considerable reductions in total signal losses and crossing delays are correlated with smaller sizes.

2.3 Increased Cost-Effectiveness

HDI boards can be more economical than other solutions with careful design and production since they use less raw materials because of their compact size and few required layers. You might be able to employ one HDI board for a product that previously would have needed several conventional PCBs. More functionality and value may be obtained with a smaller footprint and less material.

2.4 Faster Production Times

Faster manufacturing speeds and a quicker time to market can result from the capacity to utilize less resources, and even fewer boards, in combination with design savings tied to HDI technology. Due to the superior electrical performance and relatively simple component placement, HDI PCBs require less time to test and debug.

2.5 Enhanced Reliability

The dependability of your board and your goods can be increased by the reduced aspect ratios and the premium micro via structure. Reduced costs and higher customer satisfaction are the results of the enhanced performance and dependability HDI PCBs offer.

2.6 Better Signal Transmission

Signals’ route length is cut down using HDI PCBs to enable rapid transmission. This is so because an HDI PCB has closer-spaced circuit components.

3. Manufacturing Of HDI PCB

There are a few small but significant ways in which the HDI PCB manufacturing process varies from the conventional PCB manufacturing method. It’s crucial to note that fabricator constraints will restrict design freedom and place restrictions on the board’s routing. Although your design programmed can still support the usage of thinner traces, smaller vias, more layers, and smaller components, doing so requires taking use of automation. Design for manufacturing (DFM) requirements. The manufacturing procedure and materials utilized to construct the board will determine the precise DFM requirements. When dependability needs are taken into account, DFM requirements also become significant.

In HDI substrates, nine distinct types of general dielectric materials are employed. Many of them are covered by IPC slash sheets like IPC-4101B and IPC-4104A, while many are not yet described by IPC standards. The resources are

  • luminous liquid dielectrics
  • Dielectrics for photosensitive dry film
  • Flexible polyimide film
  • Dry sheets that have been thermally cured
  • cured thermally liquid dielectric
  • RCC foil that is double-layered, strengthened, and resin-coated
  • Standard FR-4 cores and prepregs
  • brand-new “spread-glass” laser-durable prepregs
  • Thermoplastics

The details of HDI PCB fabrication is provided as follows,

3.1 Photoresist Deposition and Exposure

This is used to specify the places that will be etched, leaving a pattern of conductors remaining on the laminate.

3.2 Etching And Cleaning

A solution of ferric chloride serves as the industry standard etchant at the moment. The resultant conductor design may be cleaned after etching, and any residual photoresist can be recovered.

3.3 Via Formation and Drilling

Mechanical or laser drilling must be used to define the vias. The through holes can be eliminated chemically for increased via density.

3.4 Via Metallization

Vias are metallized to provide a continuous conductive link after being defined.

3.5 Build-Up

Before treating the outer layer, layers are piled over several cycles of lamination.

Although HDI PCB processing techniques are more sophisticated than conventional rigid PCB processing procedures, they nonetheless employ the same manufacturing data as a standard rigid PCB. Deliverables for your fabricator and assembler should be ready after your HDI PCB layout is done and has passed a DFM review. All of your design information is used by Altium Designer’s unified design environment to produce fabrication files in Gerber’s/ODB++/IPC-2581, drill tables, a bill of materials, and assembly drawings for your new HDI PCB.

4. Advantages Of HDI PCB

Because standard printed circuit boards can no longer satiate the needs of rapidly evolving sectors, HDI PCB is a product of societal evolution.

High-density interconnect circuit board, or HDI PCB for short, is a term used to describe leaving extra space on a printed circuit board in order to increase efficiency and transmission speed. The printed circuit board industry’s fastest growing segment is high-density interconnect circuit boards.

  1. The circuit board will definitely get thinner and thinner as technology advances, and the aperture will eventually get smaller and smaller. Warpage needs to meet very strict specifications in order to fit the SMD packaging.
  2. From the standpoint of market development, the rise in market demand for HDI PCBs must be unavoidable given the growing need for motherboards in technological goods like computers and mobile phones, as well as the explosive growth of the electric vehicle sector. In the medical, aviation, and military industries, HDI PCB is crucial.
  3. From a technological standpoint, HDI PCB contains inner and outer circuits thanks to micro-blind buried via technology. Drilling, hole metallization, and other procedures are then employed to create the internal connection of each layer of circuits. High-end HDI uses build-up techniques that are two times or more effective while using cutting-edge PCB techniques including stacking holes, electroplating hole filling, and laser direct drilling. In comparison to standard PCB, HDI PCB is more flexible, supports the use of cutting-edge packaging technology, and offers superior electrical performance and signal accuracy. Additionally, HDI PCB has higher advancements for heat conduction, electrostatic discharge, radio frequency interference, and electromagnetic wave interference.
  4. An HDI board’s overall design is highly sturdy and uses a system called “via-in-pad.” By allowing components to be deposited closer to one another, this cycle reduces the signal path distance. The one all-around disposition is naturally improved in this way.
  5. Your device’s overall enactment can be considerably improved by using an HDI rather than a regular PCB. You may get a promising electronic performance and appropriate signal integrity with HDI boards. Without sacrificing the electrical executions, an HDI PCB may provide a president terminal version that is more practical.
  6. An HDI is far more dependable than a typical PCB. Whatever the situation, the implementation of heaped vias gives the boards their maximum strength and resistance. Therefore, after you make an investment in an HDI, you won’t need to worry about its performance for a while.
  7. If you get your hands on an HDI PCB, you can make every cent matter. This PCB guarantees high quality and robust performance at no additional cost. It functions as an integrated circuit board. Therefore, once you spend your money on a high-quality HDI board, you no longer need to buy many standard PCBs for various programmers. You may save a sizable sum of money in this method.
  8. A conventional PCB can be made much more quickly than an HDI PCB. A small number of components are required to create an HDI board. As a result, the process as a whole takes less time. As opposed to that, it gives the mount particles a lot more room, uses less power, and is lighter than conventional PCBs. Therefore, using an HDI circuit board is much more profitable than spending a fortune on faulty ones.
  9.  Increased circuit density is possible thanks to the requirement for the lines and via-hole conductors (fan-in and fan-out) that are pulled out around the QFP to link the junction of conventional circuit boards and components. The following layer’s connector wire can be concealed using micro via technology. The blind holes in the pads serve as direct connections between the leads and pads between different levels, negating the requirement for fan-in and fan-out wiring. In order to accommodate more parts, various pads (such mini-BGA or CSP tiny ball bonding) can be added on the outer layer board, increasing the density of the circuit board. This unique stacking and wiring technique is widely used in small-sized wireless phone handset boards with excellent functionality.
  10. Improve radio frequency interference, electromagnetic wave interference, and electrostatic discharge (RFI, EMI, and ESD): Micro via technology enables circuit board designers to reduce radio frequency interference and electromagnetic wave interference by shortening the distance between the ground layer and the signal layer; however, the number of ground wires can be increased to prevent damage to the components of the circuit from the instantaneous discharge caused by static electricity.
  11. Boost design efficiency: The inner layer arrangement made possible by micro through technology gives the circuit designer greater design space and enables for improved design efficiency.
ELE PCB is able to fulfil all of your needs for HDI PCBs, beginning with the prototype phase and continuing all the way through the production process. Because of our knowledge and experience in the field of manufacturing multilayer printed circuit boards, we hold a significant advantage over our competitors in the industry of generating printed circuit boards. In addition, we never promise a price that is greater than the prices offered by our rivals, and we never require customers to buy a certain minimum amount of any product with each order that they place.

5. ELE Technology Co. The Leading China HDI PCB Board Maker

Prototyping printed circuit boards (PCBs) is a useful technique for designers since it helps save time and money while guaranteeing a high-quality result. Get in touch with ELE PCB right away if you need PCB prototype services for an upcoming venture.

Over 6,000 engineers and 300 contract assemblers from across the world rely on ELE PCB for their HDI PCB prototype services. We pride ourselves on our dedication to quality and our ability to consistently provide fully functional prototypes that meet or exceed your requirements. Whether you need a simple two-sided FR4 board or a very complicated multi-layered prototype, our PCB design professionals have you covered. Your prototype may be provided by ELE PCB promptly, proficiently, and cheaply, with no hidden expenses.

Our method is straightforward; we utilize CAD software to plan the layout of the prototype, select the manufacturing material, and then cut and assemble the board. After that, the circuit board is complete and ready for testing. And when the time comes, we’ll assist you in making the jump from prototype to production.

ELE PCB is here to assist you if you’re in the market for professional PCB prototype services. Get in touch with us now and talk to a member of our service team about your PCB prototyping needs and how ELE PCB can fulfill them.


TypeRigid, Flexible, Rigid-Flexible
MaterialFR4, CEM1, CEM3, Aluminum, High Frequency Board
Layer1, 2, 4, 6 … 24Layers
ShapeRectangular, Round, Slots, Cutouts, Complex, Irregular
CuttingShear, V-score, Tab-routed
Board Thickness0.2-4mm, regular 1.6mm
Copper Thickness0.5-4oz, regular 1oz
Solder MaskGreen, Red, Blue, Yellow, etc.
Silk ScreenWhite, Black, etc.
Silk Screen Min Line Width0.006″ or 0.15mm
Min Trace/Gap0.1mm or 4mils
Min Drill Hole Diameter0.01″, 0.25mm or 10mils
Surface FinishHASL, ENIG, OSP, etc.


ELE PCB has got the IS09001:2015, IS013485:2016, ROHS and FCC certifications. We can offer all kinds of services, including PCB manufacturing and PCB assembly, sample orders and batch orders. For PCB assembly, utilizing 7 high-speed SMT PCBA lines from Yamaha and Sony, to meet our customers’ needs. Our extended services include PCB design &PCB Layout, hardware design engineering, firmware &software development, and personalization. ELE company is honored as an excellent supplier from any company all around the world. We deeply believe that our good service and experience will completely meet your needs. Integrality, value and innovation are the forces that drive our success.



We provide technical expertise form prototype through production increasing speed to market by 20%.

                   Contact us below to start discussing your project with our Technical Experts today.

                   Whether you already have Gerber Files, submit a Quick Quote for free estimate.