HDI Board Design Support High-Speed Communication
Increasingly complex electronic devices demand high performance in a smaller space, and HDI PCBs are ideal for these applications. High-density interconnections allow you to pack more components and signals in a small space, and they also reduce the interference between them. This increases the reliability and effectiveness of your electronic device, and allows it to run at a faster speed. These factors make HDI circuit boards suitable for use in a wide range of applications, including mobile / cell phones, touch-screen devices, laptop computers, digital cameras and 4/5G network communications. They can also be found in medical equipment like monitors, X-ray machines and implantable pacemakers.
Designed to support high-speed communication, hdi board feature a dense stackup construction and microvias that connect the signal layers of the board. They have a lower layer count than standard multilayer PCBs, and they typically have a higher dielectric thickness. These features can improve manufacturability, field performance and service life. They are also more resilient to thermal and mechanical shocks.
In addition to the increased layer count and dielectric thickness, HDI circuit boards use a sequential lamination process to form their structure. They are constructed in layers, with a copper foil and one or more dielectrics. The copper foil is plated with gold for conductors, and the layers of dielectric are laminated together to create a rigid board. The board is then laminated with a clear film for protection and to prevent moisture damage.
How Does HDI Board Design Support High-Speed Communication?
An important part of the HDI circuit board design is the selection of materials for the dielectrics and copper foil. The dielectric must be compatible with the copper, and it must have an adequate adhesion strength to maintain a strong bond during the lamination process. It must also have a high glass transition temperature (Tg) to withstand thermal fluctuations and wire bonding. In addition, it must provide good electrical insulation and a high resistance to moisture.
Another crucial factor is the layout of the signals. Since the traces on an HDI circuit board are much closer together than in regular PCBs, you must route them carefully. Using impedance-controlled routing, you can ensure that all of the signals on your PCB have the same impedance. This will keep the signal timing accurate and reduce noise and jitter.
Another critical aspect of the HDI circuit board design is ensuring that your layout meets the fabrication manufacturer’s DFM guidelines. These rules include the thickness of the dielectrics and the aspect ratio for the microvias. If these aren’t met, you may encounter issues such as shorting, overheating or poor signal performance. Fortunately, the DRC engine in your PCB design software can help you keep track of these rules as you layout your circuit board. This will ensure that your final product is robust and reliable. To get started designing your bare HDI circuit board, try the free Altium Designer software today. It includes an integrated design rules engine and layer Stack Manager, and it can calculate your impedance and account for copper roughness.
