From the first 32-bit computer launched by Hewlett-Packard in 1985 to today's large client server with 36 sequential laminated multilayer printed boards and stacked micro vias, HDI micro via technology is undoubtedly the future PCB architecture. HDI is the abbreviation of High Density Interconnector in English. High Density Interconnect (HDI) manufacturing is the fastest growing field in the printed circuit board industry.

Due to the rapid development of high technology and electronic design, while improving the performance of the whole machine, it is also working hard to reduce its size. In small portable products ranging from mobile phones to smart wearable devices, small is an everlasting pursuit. High-density integration (HDI) technology can make terminal product designs more compact, while meeting higher standards of electronic performance and efficiency.
At present, most popular electronic products are HDI boards, such as mobile phones, digital (camcorder) cameras, notebook computers, automotive electronics and other digital products. With the upgrading of electronic products and market demand, the development of HDI boards will be very rapid. Numerous electronic products have begun to develop in the direction of light, thin and short, and high-density, interconnection boards (HDI) have adapted to the needs of the market and have come to the forefront of PCB technology development.

HDI: High-density interconnection technology. It is a multilayer board made of stacking method and micro-blind buried vias.
Micro-hole: In the PCB, a hole with a diameter of less than 6 mils (150μm),which is buried in the inner layer of the hole and is not visible in the finished product, are called as buried via hole. It is mainly used for the conduction of the inner line and can reduce signal interference. Probability, and maintain the continuity of the characteristic impedance of the transmission line. Since the buried vias do not occupy the surface area of ​the PCB, more components can be placed on the surface of the PCB.
Blind hole: Connect the surface layer and the inner layer without passing through a complete-through hole.
HDI PCB are generally manufactured by the build-up method. The more laymination times, the higher the technical grade of the board. Ordinary HDI boards are basically one-time lamination. High-end HDI uses two-time or more laminating technology. At the same time, advanced PCB technologies are used during the production including stacking holes, copper plugging vias, and laser direct drilling. High-end HDI boards are mainly used in 3G mobile phones, advanced digital cameras, IC carrier boards, etc.
How to identify the 1st, 2nd and 3rd order of HDI circuit board
The easiest thing for everyone to understand is: Level 1 is the easiest to produce, and it is relatively easy to control in terms of parameters and technology. Tier 2 and above are relatively difficult, especially Tier 5 is the most difficult to control.
The first-order is relatively simple, and the process and craftsmanship are well controlled.
1. Drill holes after pressing once == "Press the copper foil again on the outside == "Then laser drill holes, this is the first order
2. Drill holes after pressing once ==》Press the copper foil again on the outside ==》Laser again==》Press the copper foil again on the outer layer ==》Drill the laser again. This is the second order. It mainly depends on the number of times your laser has been shot, which is the order. There are two kinds of second-order stacked holes and bifurcated holes.
The second order started to be troublesome, one was the alignment problem, and the other was the hole punching and copper plating problem. There are many types of second-order designs. One is that the positions of each step are staggered. When connecting the next adjacent layer, it is connected through a wire in the middle layer, which is equivalent to two first-order HDI.
The second is the overlap of two first-order holes. The second-order is achieved by superposition. The processing is similar to two first-order holes, but there are many process points to be specially controlled, which is mentioned above.
The third type is to punch directly from the outer layer to the third layer (or N-2 layer). The process is different from the previous one, and the difficulty of punching is also greater.
The third order, the fourth order and so on.
Therefore, the higher the application of HDI technology, the higher the level of laminate manufacturing. The ordinary HDI board is laminated once, and the high-end HDI uses two, three or more lamination processes, as well as electroplating hole filling, pile hole, laser direct drilling, etc.

Are all blind and buried PCB circuit boards called HDI PCB?
The hdi board is a high-density interconnect circuit board. The boards pressed twice after the blind hole plating are HDI boards. HDI boards are divided into 1, 2, 3, 4 and 5 HDI boards. For example, for mobile phones after iphone6, the motherboard uses 5-level HDI. So simple buried vias are not necessarily hdi circuit boards.
HDI PCB development prospects:
According to the use of high-end HDI panels, its future growth is very rapid. In the next few years, the growth of 5G mobile phones in the world will increase exponentially, and the development prospect of HDI is very impressive. If you have HDI PCB requirements, please contact us! We will give you the best service with best price!