Explore HDI PCB: Know Everything from Advantages to Design Precautions!

HDI PCB is a kind of high - density PCB with a very small circuit space. HDI PCBs are widely used in smart - phone motherboards, server circuit boards, POS motherboards, monitor motherboards, automotive circuits, Android smart - device motherboards, tablet - computer motherboards, drone controllers, and so on.

I. What are the advantages of HDI PCB?

1. Reduces PCB cost. When the density of PCB increases to more than eight layers, the manufacturing cost of using PCB HDI will be lower than that of the traditional complex stamping process.

2. Increases circuit density, which is beneficial to the interconnection between traditional circuit boards and components.

3. Is conducive to the adoption of advanced construction techniques.

4. Has better power efficiency and signal accuracy.

5. Has good reliability.

6. Can improve thermal efficiency.

7. Improves radio - frequency interference/electromagnetic - wave interference/electrostatic - discharge.

II. What are the differences between HDI PCB and standard printed circuit boards?

1. Ordinary PCBs are basically laminated in one - time. High - end HDI PCBs adopt two or more lamination technologies and advanced PCB technologies such as via - in - pad, plated - via filling, and laser - direct - drilling. The more times of lamination, the higher the technological level of the PCB board.

2. The power efficiency and signal accuracy of HDI PCB are higher than those of standard PCB.

3. HDI PCB has blind - plated vias and is laminated twice, divided into first - order (1 + n + 1), second - order (2 + n + 2), third - order (3 + n + 3), fourth - order (4 + n + 4), fifth - order (5 + n + 5), and arbitrary - order, etc. The first - order is relatively simple, and the process and procedures are easy to control. The main problems of the second - order are alignment, punching, and copper plating.

There are many designs for the second - order. One is that each order is staggered. When it is necessary to connect the second - adjacent layers, it is connected by wires in the middle layer, which is equivalent to two first - order HDIs. The second is that two first - order holes overlap, and the second - order holes are realized through superposition. The processing is also similar to that of two first - order holes, but there are many critical process points that need to be specially controlled, as mentioned above. The third is to drill directly from the outer layer to the third layer (or n - 2 layer). This process is different from the previous one, and the drilling is more difficult. For the third - order, the second - order simulation is used.

III. What should be noted in HDI PCB design?

1. In the areas with higher component density on the PCB, HDI PCBs use microvias instead of through - holes.

2. Improve the layout of the routing holes of HDI PCBs. In the design of HDI PCB boards, the rational layout of holes is very important, aiming to provide better signal integrity and improve the internal routing space.

3. Replace through - holes with microvias. For PCB designs, finer pitch BGAs are becoming increasingly complex, and HDI PCB designs provide space for staggered holes and blind holes.

4. How to design the HDI PCB stack?

(1) Trace size: You need to adjust the size of the traces to an appropriate width and thickness to ensure that the impedance is controlled. Another way is to look at the BGA pitch, set the upper limit of the line width, and use this value to determine the layer thickness required for the desired line impedance.

(2) Estimate the net quantity of each layer: Once the required line width/layer thickness is determined, you can roughly determine how much space the signal layers will occupy within the HDI PCB layout area.

(3) Number of HDI PCB layers: Once you know the number of nets required for each layer, simply divide your total number of nets by this number to get the number of layers.

HDI PCBs require PCB manufacturers to have strong competitiveness and manufacturing process capabilities. Many PCB manufacturers pay high attention to HDI PCB manufacturing and assembly. Close communication with HDI PCB manufacturers can save manufacturing costs and ensure better HDI PCB manufacturing.

PCB MASTER Company is a professional Chinese HDI PCB manufacturer. We provide high - precision HDI PCB manufacturing and cost - effective HDI PCB products. If you need a quotation for HDI PCBs, please send us an email.