Comparison of PCB Materials for High Speed and HDI PCB Boards

Section: How to Select PCB Materials?

Takeaway: When selecting PCB materials, you need to be aware of some of the factors that can influence your selection.

Section: Factors Influencing PCB Materials Choice


HDI and high speed PCBs are two different types of boards that are used in printed circuit board (PCB) production.

HDI PCBs are used in applications that require high speed, high density and high reliability. The board consists of an interconnecting layer made up of copper traces to connect the various components together. In addition, the HDI board also has a core that can be used to protect sensitive components on one side while allowing for better heat dissipation on the other side.

HDI PCBs are also used in applications that require high power and high data transfer rates; for example, they’re often used in aerospace or military applications where failure is not an option.

High-Speed PCBs

High-speed PCBs are designed to operate at high frequencies, and are therefore used in radar, satellite communications, and military applications. This type of board has a minimum frequency rating of 3 GHz (3 gigahertz). FR4 material is commonly used as the dielectric substrate for high speed boards because it has good thermal stability and strength characteristics. Glass fiber reinforced epoxy laminate materials like FR4 provide superior electrical performance over other types of substrates such as glass or ceramic.


High-density interconnect (HDI) is a type of PCB material that is used in high speed applications. It’s more expensive than standard PCBs because it’s more complex to make.

It has been found that HDI boards tend to be less flexible, making them less suitable for flex circuit designs and more sensitive to mechanical damage from handling or rubbing against other components. In addition, they can have problems with soldering due to their increased resistance when applying solder paste onto the copper surface hdi pcb boards (as compared to standard copper clad boards).

The choice of material for your high speed or HDI boards is important and should be based on the application.

The choice of material for your high speed or HDI boards is important and should be based on the application. High speed boards are used in applications that require high speeds and low latency, such as communications equipment, while HDI boards are used in applications that require high bandwidth and high density, such as computing systems.

High-speed PCBs can be produced with FR-4 epoxy resin, glass fiber reinforced epoxy resin (GFRP) or carbon fiber reinforced epoxy resin (CFRP). These materials are suitable for most standard applications up to 1 GHz. Beyond 1 GHz, leaded silicate glass epoxy (LSG) becomes necessary to reduce dielectric losses across the board at higher frequencies. The dielectric constant of LSG is lower than that of GFRP or CFRP making it more suited for high frequency applications where impedance matching between traces may be an issue due to stray capacitance from nearby traces or other components placed on the board surface.


Trim-Lok is a fastening system that allows for a PCB to be mounted from the front, bottom or sides without having to drill into the board. Instead, by inserting the PCB into the trim-lok sockets, a self-tapping screw is automatically tapped through the proper holes to provide mechanical connection of two components. It also serves as an electrical insulating material for electromagnetic interference (EMI) shielding.

Like most fasteners, there are hermetic seals used in order to prevent moisture build-up between various layers of PCBs   and their soldered connections. The most common seal used in PCB manufacturing is epoxy resin. This adhesive can be applied directly onto copper tracks on both sides of the circuit boards themselves. Once cured and time has passed, it acts as a physical barrier against moisture and prevents corrosion and oxidation within the circuit board’s printed circuitry area of concern.

While this type of seal may be sufficient enough when installed on its own, it will not necessarily protect against EMI or airborne particles that could have been picked up during transport or handling by workers while being produced elsewhere in manufacturing facilities across different countries in which they were made. Where such situations might occur are in environments with high rates of particulate pollution such as found near factories and industrial areas where outdoor exposure limits apply for protective gear and breathable masks may be needed to properly complete any job tasks surrounding materials production alongside environmental control measures all around a facility for more efficient operations under more controlled circumstances than would be found in more rural areas where individuals perform such work outside commercially owned facilities by themselves on site along with working conditions that could pose risks due to variable weather conditions during production cycles where equipment breakdowns can take place without prior forewarning due to inconsistent conditions and/or working hours full of excessive wear and tear which may cause significant damage if process steps cannot be completed correctly or even

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