High Density Interconnects Enhance Automotive Electronics
Over the past couple of decades, we’ve seen electronic devices shrink in size and weight, yet improvise phenomenally in speed and performance, without sacrificing quality or functionality. Several factors have led to this transformation, including advances in printed circuit board technology. Known as high density interconnect, or HDI PCB technology, it allows for a higher wiring density in a smaller footprint.
The process of constructing multi-layer high density interconnect boards requires specialized skills and tools, which are not as easy to master as conventional multi-layer fabrication. It involves laser drilling for microvias, layer lamination with insulating materials, copper plating and etching for precise circuit patterns, advanced surface finishes such as ENIG, and component assembly using automated processes. Rigorous testing and quality control are critical to the success of these intricate processes.
Any printed circuit board that offers dense placement of components and denser interconnections can be referred to as an HDI PCB. It can also include features such as blind and buried vias, alternative coreless construction with pairs of layers, or through-going vias with alternate sidewalls. These elements improve signal integrity, reduce crossing delays and signal losses, and increase board reliability.
How Do High Density Interconnects Enhance Automotive Electronics?
High density interconnects are also less prone to thermal degradation and harsh environmental conditions. They can be used in many different applications, such as automotive electronics, aerospace, and medical devices. They also have the potential to be more cost effective than traditional PCBs, as they are able to support higher frequencies.
Today’s automobiles rely on microprocessors to perform a number of functions, such as controlling the engine, drive, and safety systems, as well as enabling functions like onboard WiFi and GPS, backup sensors, and parking assistance. To achieve this, the vehicles require a compact sensor hub that has an integrated power supply and provides high data-throughput capacity. To meet these demands, engineers use HDI technology in the design of the vehicle’s circuitry.
Unlike traditional PCBs, which are stacked in layers, HDI boards have embedded copper on each of the four sides. These copper traces form the electrical connections between the components. These connections are then insulated from each other with a resin. This prevents the conductors from touching each other, which is a source of interference and shorting.
The HDI technology in the automotive circuitry is typically built with a semi-stacked structure that has two levels of copper-filled microvias and a staggered configuration. This avoids the reliability risks associated with stacking three levels of microvias. To mitigate this risk, designers conduct interconnection stress testing (IST) prescreening to ensure the HDI components can withstand the requirements of the system.
The HDI circuitry in automotive electronics is incredibly complex, making it more difficult to manufacture than other types of PCBs. It’s crucial for designers to pay close attention to the spacing of traces and pads when designing an HDI board. They should also resist the temptation to use staggered vias or Extra-Large Inner Connects (ELIC) unless it’s necessary to achieve the desired functionality. By paying careful attention to these details, designers can minimize the risk of manufacturing issues and achieve a successful design.
