Component Density With HDI Printed Circuit Boards
Achieving higher component density is a crucial factor in designing an efficient printed circuit board. It allows more components to be placed on the same PCB and minimizes the distance between them. This increases electrical performance and reduces power consumption. It also improves signal integrity by minimizing crossing delays and signal losses.
A high-density hdi printed circuit board can also be cost-effective because it takes less time to produce. This is because the board manufacturers can save money on materials and labor. It also makes the board easier to assemble, test and deliver to customers.
High-density PCBs are used in electronic devices that demand high-performance and conserve space, such as mobile /cellular phones, digital cameras and laptop computers. They are also found in military applications such as avionics and smart weapons, as well as in industrial automation where a need for data collection and communication is vital.
How to Achieve Higher Component Density With HDI Printed Circuit Boards
To achieve the necessary routing density in an HDI PCB, the stack-up must be carefully designed. This includes choosing the right materials, via types and sizes, as well as determining the amount of copper required for each layer. Additionally, the traces and pads must be appropriately spaced. Sierra Circuits recommends using an online tool to help you determine the minimum layer count needed for your design.
Unlike standard PCBs, which use solder as the main interconnection, HDI PCBs use either blind or buried vias to connect layers. These are holes drilled through the top and bottom of the board that link internal layers, but they’re not visible from the outside of the circuit board. Blind and buried vias are usually smaller than standard through-hole vias, but they can be any size.
When designing an HDI PCB, you should always verify the manufacturer’s capabilities and fabrication processes. These factors will influence the via sizes that are available, as well as the number of sequential laminations. The more laminations a board has, the more expensive it will be.
The type of material and surface finish you choose for your HDI PCB will also affect the cost. You can select from FR4, metal, or fiberglass cores, and you can get different surface finishes such as ENIG, HASL, immersion tin and immersion silver.
During manufacturing, the etching process separates the inner copper layers. These are then separated by partially cured laminates and stacked like a book, with layers of prepreg on the top and bottom. The prepreg is then heated and liquified to stick the layers together. For a multi-layer HDI PCB with blind or buried vias, the board will undergo several numbers of sequential laminations.
The choice of materials will have a direct impact on the quality and reliability of your finished product. For example, FR4 is the most common core material for HDI PCBs, and it provides excellent conductivity. It also has low shrink rates and a low coefficient of expansion. In addition, it is easy to machine and solder. Other options include copper clad epoxy and copper metallized polyimide (CMPI). CMPI is a more advanced material that offers better reliability and EMI shielding.