What HDI in PCB?
HDI is an abbreviation for High Density Interconnector. A HDI PCB is a circuit board that has a higher wiring density per unit area than a conventional board. HDI PCBs have finer spaces and lines, fewer vias and capture pads, and a higher density of connection pads.

HDI PCB Market Supply and Demand Analysis
Due to the miniaturization of electronic products and the development needs of integration, PCBs need to carry more components in a smaller space and better high-frequency transmission capabilities. This also makes high density interconnect (HDI) PCBs one of the fastest-growing technologies in PCBs. Because its circuit density is higher than traditional circuit boards, HDI PCB designs are able to incorporate smaller vias and capture pads, as well as higher connection pad densities. HDI boards contain blind and buried vias, and typically contain microwells with a diameter of 0.006 or even less.
Advantages of HDI PCBs
1.HDI technology aids in the reduction of PCB costs.
2.HDI PCB improves line density.
3.HDI technology makes advanced packaging more accessible.
4.HDI PCBs have superior electrical and signal effectiveness.
5.HDI technology is more dependable.
6.Heat dissipation is improved with high density PCB.
7.PCB HDI increases design efficiency.
HDI Capabilities
Feature | Technical specification |
Number of layers | 4 – 22 layers standard, 30 layers advanced |
Technology highlights | Multilayer boards with a higher connection pad density than standard boards, with finer lines/spaces, smaller via holes and capture pads allowing microvias to only penetrate select layers and also be placed in surface pads. |
HDI builds | 1+N+1, 2+N+2, 3+N+3,4+N+4, any layer in R&D |
Materials | FR4 standard, FR4 high performance, Halogen free FR4, Rogers |
Copper weights (finished) | 18μm – 70μm |
Minimum track and gap | 0.075mm / 0.075mm |
PCB thickness | 0.40mm – 3.20mm |
Maxmimum dimensions | 610mm x 450mm; dependant upon laser drilling machine |
Surface finishes available | OSP, ENIG, Immersion tin, Immersion silver, Electrolytic gold, Gold fingers |
Minimum mechanical drill | 0.15mm |
Minimum laser drill | 0.10mm standard, 0.075mm advanced |
HDI PCB Types
1st order, 2nd order, 3rd order, 4th order and arbitrary layer interconnections
1st-order HDI structure: 1+N+1 (press-fit 2 times, laser 1 time)
2nd order HDI structure: 2+N+2 (3 times pressed together, 2 times laser)
3rd order HDI structure: 3+N+3 (pressed together 4 times, laser 3 times)
4th order HDI structure: 4+N+4 (pressed together 5 times, laser 4 times)
HDI PCB Materials

- The laminated multilayer board made by photosensitive material, the substrate is filled with photosensitive resin.
- The laminated multilayer boards made of non-photoreceptor materials are mostly made of high temperature resistant FR-4 substrates or other heat resistant substrates without photoreceptor resin.
HDI PCB Manufacturing Process
- Photolithography laminated multilayer board. HDI boards with microvia formation by photographic imaging and etching.
- HDI boards with microvia formation by plasma bombardment.
- Laser hole-forming multilayer boards. HDI boards with micro vias formed by drilling with CO2 laser or UV-YAG laser.
- Chemically formed multilayer boards. HDI boards with miniature vias formed by chemical etching method.
- HDI board with micro-conducting holes formed by mask protection jet blasting method.
More Flexibility HDI PCB Layout

The evolution of high-density PCB technology has given engineers greater design freedom and flexibility than ever before. Designers using HDI high density interconnect methods now can place more components on both sides of the raw PCB if desired. In essence, an HDI PCB gives designers more space to work with, while allowing them to place smaller components even closer together. This means that a high-density interconnect PCB ultimately results in faster signal transmission along with enhanced signal quality.
Lighter Multilayer HDI PCB
HDI PCB is widely used to reduce the weight and overall dimensions of products, as well as to enhance the electrical performance of the device. The high-density PCB is regularly found in mobile phones, touch-screen devices, laptop computers, digital cameras, and 4G network communications. The HDI PCB is also prominently featured in medical devices, as well as various electronic aircraft parts and components. The possibilities for high-density interconnect PCB technology seem almost limitless.
Function improved by HDI PCB
1.Denser trace routing
2.More stable power
3.Reduce interference inductance and capacitance effects
4.Improve signal integrity in high-speed design
Accelerate Development with HDI Printed Circuit Boards
1.Easier to place SMD components
2.Faster routing
3.Reduce frequent relocation of components
4.More component space (also by Via-in-Pad)
HDI PCB Application
- Mobile communication equipment and notebook computer boards. The number of holes, light, short, small, strong function.
- High-end computer and network communication equipment and large peripheral equipment boards. The number of holes is small, the number of conductor layers is large, and the integrity of the transmitted signal and the characteristic impedance control are required.
- large-scale integrated circuit packaging chip carrier board, including pressure-soldering board (also known as wire, Wire Bonding Board) and overlay board (Flip Chip Board) and so on. Line width and spacing is small (generally less than 2mil), high precision, small hole diameter (1 ~ 2mil), small hole spacing (≤ 5mil), good heat resistance of the substrate, the coefficient of thermal expansion is small.
GESP Your Reliable HDI PCB Manufacturer
GESP Technology offers a wide range of HDI structures and processes to meet your PCB needs and brings you a better compromise between technology and cost.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 to discuss it. Sent your needs and production documents through our Contact us interface. We will respond to you within 24 hours.