What is HDI PCB

HDI PCBs are the future of PCBs and their popularity will only continue to grow. If you're looking for a high-density PCB, look no further than HDI. HDI PCB is a PCB with higher component density than traditional PCB. Increases in density can be achieved through the use of smaller components and more advanced manufacturing techniques. HDI PCBs are used in a variety of applications including smartphones, tablets, and other consumer electronics. They are also used in various industrial and medical applications.

In addition to smartphones, tablet and desktop makers are striving to achieve miniaturization. All these size reductions depend on the design and use of High Density Interconnect PCB (HDI PCB prototype). The functions of HDI technology are designed to make smart devices lighter, smaller, thinner and more reliable.

HDI (High Density Interconnect) is a compact circuit board designed for small capacity users. Compared with ordinary pcbs, the most notable feature of HDI PCB prototypes is the high wiring density.

Advantages of HDI PCB Prototyping

HDI PCB prototypes rely on lasers rather than mechanical drilling. In turn, HDI PCB prototyping achieves smaller apertures and smaller pad sizes. Reducing the aperture allows the HDI PCB prototyping team to increase the layout of the board area. Shorter electrical paths and denser trace routing improve the design's signal integrity and speed up signal processing.

Instead of through holes, HDI PCB prototyping uses blind and buried vias. Staggered and accurate placement of buried and blind vias reduces mechanical stress on the board and prevents any chance of warpage. Additionally, stacked vias can be used to enhance interconnect points and increase reliability. The use of pads also reduces signal loss by reducing crossover delays and mitigating parasitic effects.

HDI PCB prototype complexity, these factors have shifted the focus to the planning, layout and fabrication of HDI PCB prototyping. HDI PCB prototypes are generally manufactured by lamination method. The more times of lamination, the higher the technical grade of the board. Ordinary HDI PCB prototypes are basically one-time build-up, while high-end HDI PCB prototypes use two or more build-up technologies, while using advanced PCB technologies such as stacked holes, electroplating and filling holes, and laser direct drilling. When the density of the PCB increases to more than eight layers, the cost of manufacturing HDI PCB prototypes will be lower than the traditional and complicated lamination process.

HDI PCB prototypes have higher electrical performance and signal accuracy than traditional PCBs. In addition, HDI boards have better improvements in radio frequency interference, electromagnetic wave interference, electrostatic discharge, and heat conduction. High-density integration (HDI PCB prototyping) technology can enable more miniaturized end-product designs while meeting higher standards for electronic performance and efficiency.

The HDI PCB prototype uses blind hole plating and then performs secondary lamination, which is divided into first-order, second-order, third-order, fourth-order, and fifth-order. The first-order is relatively simple, and the process and process are easy to control. The main problems of the second order, one is the alignment problem, and the other is the problem of drilling and copper plating. There are many second-order designs. One is that the positions of each stage are staggered, and when the next adjacent layer needs to be connected, it is connected through a wire in the middle layer. The method is equivalent to two first-order HDIs. The second is that two first-order holes overlap, and the second-order is realized by superposition. HDI PCB prototype processing is also similar to two first-order holes, but there are many process points that need to be specially controlled, which is the above mentioned. The third is to punch holes directly from the outer layer to the third layer (or N-2 layer). The HDI PCB prototype process is much different from the previous one, and it is more difficult to punch holes. For the third order, the second order is analogized.

HDI PCB Prototype Material Selection

Material type and construction are extremely important for HDI PCB prototypes. Designing HDI PCB prototype interconnects requires an understanding of the issues that can arise when specifying glass-reinforced dielectric materials. Whether drilled with plasma, laser, or mechanically, microporous dielectric materials can result in misregistration and rough holes.

Copper Clad Laminate (CL): Copper Clad Laminate material laminates copper foil to one or both sides of a cured (Class C) dielectric. Rigid CCL can be FR4, FR-5 or some PTFE. A typical HDI PCB prototype is to use a single-sided clad board material, where the copper clad laminate is used as the outer layer, and the c-level is bonded to the sub-composite. Microholes are formed using a laser drilling method. Available materials vary by reinforcement (woven glass, non-woven glass, and expanded PTFE) and the chemistry involved (epoxy, polyimide, polyester, etc.).

Resin-coated copper (RCC): Resin-coated copper material is a compromise of copper foil, coated with a resin dielectric material that can be bonded directly to the sub-composite. They differ in that they are wet processable. In non-wet machinable coated copper materials, microholes are formed by plasma or laser drilling methods.

●PP: Prepreg, also known as B-stage, Bonding sheet, or Preg for short, is made of glass fiber cloth impregnated with resin. During the prepreg coating operation, the resin is partially cured but not hardened. When the PCB stack is heated during the pressing process, the resin in the PP will flow, adhere and bond with the copper foil or other materials to the PCB core.

HDI PCB Prototype Difficulties

HDI PCB prototype motherboards are mainly divided into first-order, second-order, third-order, and Anylayer HDI. The feature size is gradually reduced, and the manufacturing difficulty is gradually increased. At present, the third-order, fourth-order or Anylayer HDI motherboards are widely used in electronic terminal products. Anylayer HDI is known as any order or any layer HDI motherboard. Difficulties that HDI PCB prototypes need to solve:

• The thickness of the plating layer of the HDI PCB prototype should be uniform;

• The HDI PCB prototype adopts the standard of plating on the thin base copper board with high current density and the thickness of the electroplated copper layer is uniform and the same;

• In view of the through-holes and micro-holes of the HDI PCB prototype, the plating solution is required to have good dispersion;

• According to the through hole and micro hole of the HDI PCB prototype, the minimum concavity is required in the same plating solution;

• HDI PCB prototypes can increase output by optimizing equipment and current density;

• The HDI PCB prototype has no serious pollution on the surface layer of copper, the finish of the coating is small, and the serious pollution of the plating solution is small;

• The optimized plating solution for the HDI PCB prototype can control the substrate copper within the range of 1-5μM

In addition, because the electroplating process has an important impact on the performance of HDI PCB prototype products, especially HDI high-performance products, it is very important to control the uniformity of electroplating. With the emergence of higher demand and market for HDI, related HDI PCB prototype manufacturers are becoming more and more cautious in the selection of electroplating equipment.

HDI PCB prototype manufacturer

Huihe circuit is a professional HDI PCB prototype manufacturer, with more than ten years of HDI production experience and better yield. HDI PCB prototype manufacturer guarantees integrated management system and quality management system. HDI PCB prototype manufacturer follows the most strict rule system when selecting PCB raw materials.

HDI PCB prototype suppliers In China

Professional high-end HDI PCB prototype suppliers, proofing can do 20 layers of level 3, batch can do 14 layers of level 2. HDI PCB prototype suppliers superior quality products, provide one-stop PCB, SMT and BOM with single service.