8 Layer High Density HDI PCB Fr408 Isola printed circuit board

HDI PCB Basic introduction:

Layer: 8

Material: Isola fr408

Min line:4mil

Surface finish: immersion gold


Special technology: gold sided

Why HDI?

HDI offers a number of advantages in the areas of performance, package size, and overall weight. The combination of these makes HDI particularly attractive when applied to handheld, wearable and mobile electronics.

The primary motivation for HDI is simple: a larger number of transistors in a device provides more function and higher performance. In addition to increases in performance from using more powerful, more compact devices in a given product, the actual geometry of a high-density design can itself enhance performance.

Shorter traces (whether on-chip traces or the traces on the HDI board) reduce the amount of time it takes an electrical signal to travel between components. As another electrical advantage, smaller vias between devices (especially when coupled with smaller traces inside the devices) reduce the overall capacitance in the circuit, which reduces the rise time for the signal. In addition, inductance is reduced with a high-density design, lowering the effect on neighboring leads and pins. This has been one case where HDI’s ability to place more transistors on a PCB has not only led to greater functionality on that device, but also to greater performance.

Progression of Technologies

The technological advances that make modern HDI possible are essentially a dance between device makers and PCB designers, each of which offers new techniques that require, or sometimes permit, the other to move forward with device density.

As integrated circuits became more powerful and smaller, the technology for mounting them to PCBs had to adapt to take full advantage of the newer devices. Early dense ICs included ball-grid array (BGA) devices, in which the entire underside of the device was available for connections, rather than packaging with pins along each side as in the dual-inline package (DIP) designs previously standard in IC construction. BGA mounts, with their very short leads, provided an important step towards the reduction of inductance-related signal distortion that helped the overall performance of HDI designs. The primary negative with BGA devices was the initial cost of converting to machinery that performed the task of mounting the BGA to the PCB; the wave-solder machines which were the mainstay of through-mounted DIP assembly were incapable of the surface-mount assembly required by BGA devices.

Chip-scale packages (CSP) took the BGA principle to the next level. Originally called “chip-size packages,” CSP components were designed with the intention that the device would be no larger than the chip itself, with BGA-type leads on the bottom of the device. The name change reflected the packaging needs, which initially defined CSP devices as being no more than 1.2 times the size of the chip on which the device was based. However, as semiconductor manufacturing techniques were refined (and as Moore’s Law continued to prove accurate), the chips themselves shrank but the package size itself remained constant. The definition of CSP changed to refer to devices with a mounting ball pitch of no more than 1mm.


If you're in a fast-moving industry, you need to know about high density interconnect printed circuit boards. If your company isn't using them now, they probably will be soon. If they aren't, you can be sure your competitors are using them, so you need to learn about HDI PCBs and their benefits fast.

High density interconnect PCBs are a way of making more room on your printed circuit board to make them more efficient and allow for faster transmission. It's relatively easy for most enterprising companies that are using printed circuit boards to see how this can benefit them

High density interconnect (HDI) PCBs represent one of the fastest-growing segments of the printed circuit board market. Because of its higher circuitry density, the HDI PCB design can incorporate finer lines and spaces, smaller vias and capture pads, and higher connection pad densities. A high-density PCB features blind and buried vias and often contains microvias that are .006 in diameter or even less.

HDI PCB Applications

HDI PCBs are appropriate for a wide range of industries. As mentioned above, you'll find them in all types of digital devices, like smartphones and tablets, where miniaturization is key to the effective application of the product. You can also find high-density interconnect PCBs in automobiles, aircraft and other vehicles that rely on electronics.

One of the most critical areas where the high-density PCB is making huge inroads is in the medical arena. Medical devices frequently need small packages with high transmission rates that only HDI PCBs can supply. For example, an implant needs to be small enough to fit in the human body, but any electronics involved in that implant absolutely must efficiently allow for high-speed signal transmission. Here, the HDI PCB indeed is a godsend. HDI PCBs can also be useful in other medical equipment, like emergency room monitors, CT scans and much more.

No matter your industry, you're probably already getting some ideas about how high-density interconnect PCBs can make the electronics you produce or use even better - get in touch with us PCBCart to discuss it. We'll let you know if you're on the right track and help you decide exactly how beneficial an HDI PCB can be to your industry. Then, you can determine whether or not to take the next step.

What Is Different About HDI PCBs?

High Density Interconnected printed circuit boards (HDI PCB) have made technological advancements in electronics possible. They have been referred to under a variety of names: Sequence Build Up (SBU), Microvia Process (MVP), and Build Up Multilayer (BUM) boards, to name a few. Eventually the IPC (Association Connecting Electronics Industries) adopted the HDI term for consistent terminology across countries and industries.

HDI PCBs possess technical characteristics of extremely high density routing interconnections and make high density of components possible. These attributes contribute to the high performance and light weight of HDI boards that make them ideal for powering today’s devices. HDI PCBs are a perfect solution for the shrinking footprint of electronics technology, comprising the core components of such technical marvels as laptop computers, tablets, smart phones, and even wearable technology such as fitness bands and virtual reality devices.

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