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How to Manufacture the HDI PCB?

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Thur, Dec 19, 2019

Printed circuit boards are essential to the correct operation of several different devices. Traditional PCBs are created using acid or some other form of etching that creates pathways in the board that lead to different components.


These pathways are used for energy transfer. When the energy is transferred through the pathway, it causes the device that contains the PCB to perform a task or function. When there are issues with a device, the printed circuit board may be the problem. This, however, is only how a regular printed circuit board performs.


There are different types of circuit boards that are used for different things. In today’s post, you will learn more about High-Density Interconnector printed circuit boards, also known as HDI PCBs. Specifically, you will learn what an HDI PCB is, how they are made, and some of the devices that use HDI PCBs.



What is HDI PCB?

An HDI PCB is a printed circuit board that has a higher writing density per area than a regular printed circuit board. This means that the board contains more components with finer pathways and connection pads with higher densities.


There are six main types of HDI PCBs:

· Passive substrate with no electrical connection

· Alternate constructions of coreless constructions using layer pairs.

· Coreless construction using layer pairs

· Vias from the surface to surface

· Buried vias through vias

· Two or more HDI layer with through vias


How to manufacture HDI PCB

Creating HDI PCBs requires a lot of technician specialization, careful processes, and special equipment. Special equipment used in the HDI PCB manufacturing process includes plugging, laser drills, laser imaging, and sequential lamination cycles.


Laser drilling technology is very important in the creation of HDI PCBs. Traditional PCBs are typically created using acid. Some contact imaging processes are still being used today simply because the laser imaging process is costly. However, since the pathways to other components must be thin and compact, lasers are the best option for the creation process. This means that some of the traditional issues technicians may face with PCBs, such as acute angles, will not be an issue in HDI PCBs.


The beam of light used in this process is 20 microns, or 1 Mil in diameter, and is able to cut slightly through the metal and glass on the board to make tiny paths. The metal and glass used for HDI PCBs have a higher heat resistance, which makes this process possible.


Because there are thinner pathways to the components, careful work is a must. This means that the process often takes a lot longer than making a traditional PCB. Since the pathways are much finer and there are an increased number of components on the board and more electrical signals being sent, some precautions must be taken in the manufacturing process. The technician must include high-frequency transmission capabilities, impedance control, and establish a way to reduce unnecessary radiation.


To accomplish this, many manufacturers use a multi-layered design using an insulating material. This makes different pathways on thinner HDI PCBs that are then layered to allow for the full functioning of the device that the HDI PCB will power.  

After the HDI PCBs are etched, they are put together through a lamination process. The layers are laid on top of one another and a heated roller method is used. The materials are preheated so that there is a consistent stable exit temperature in each board that is created.




There are a number of items that HDI PCBs are used for. Perhaps the most popular thing HDI PCBs are used for is probably sitting in your hands at this very moment: smartphones.


Due to the complex tasks that smartphones must achieve, HDI PCBs are the best choice as they have a higher surface area for smaller pathways that can send and receive electrical signals quickly and easily. For example, the HDI PCB in a cellphone is considered the brain of the cell phone. This means the electrical signals sent through the circuit board help to perform functions such as key recognition and display.


Next, gaming consoles typically use HDI PCBs. Gaming consoles such as PlayStation, Xbox, Switch, and even the older Nintendo consoles each perform complex interactions to allow a player to play through a game. In this case, an HDI PCB in a gaming console might communicate with the game controller and display to be sure the gaming process is smooth and enjoyable.


Another popular device that contains HDI PCBs is personal computers or laptop computers. These compact devices allow for working on the go, surfing the web, or even video gaming. The HDI PCBs in this device is used to connect with the display, recognize keystrokes, and even connect with the mouse. Without a properly working HDI PCB, the laptop would be defunct.


Digital cameras also use HDI PCBs to perform difficult tasks that result in lasting memories. Digital cameras have a lot of functions and options when it comes to capturing something at the moment. From ISO and F-stop settings to color balance and exposure, the HDI PCBs in digital cameras and DSLRs are important for their function.


Lastly, HDI PCBs are typically the type of printed circuit boards used in MP3s or other music devices. This is because of complex and multiple interaction options from choosing a song, playing the song, pausing a song, skipping a song, and so forth.



High-Density Interconnector printed circuit boards are so important for the use of some of our favorite devices. In addition, they have made the capabilities of these devices increase throughout the years.


For example, cellphones used to be heavy and clunky, and really only gave us the ability to talk and text. But now, we can have an entire computer and personal assistant at the tips of our fingers thanks to the development of HDI PCBs.


This article taught you a lot about the creative process and uses of the HDI PCB.