High Density Interconnects Bend
In order for flexible electronic devices to function properly, metal interconnects must facilitate the flow of electrical signals across device components. Typically, these conductors are rigid and rigid-flex. However, recent endeavors are making flexible interconnects more practical for a range of applications, including e-textiles and flexible batteries.
High Density Interconnect (HDI) technology is a key part of printed circuit board design and manufacturing. It allows engineers to create smaller PCBs with higher circuit density, allowing more features and components to be included in a small space. In addition, high density interconnect PCBs are capable of transmitting signals faster and with greater accuracy than standard copper wires. These advantages make HDI technology essential to the miniaturization of electronic products.
To increase the circuitry density of a PCB, designers must minimize pad size and increase routing paths between pads. To do this, engineers use buried and blind vias. These small holes can pass through multiple layers of a multilayer circuit board without exposing the outer surface. Compared to traditional circuit boards, HDI PCBs feature 2X to 3X more average trace lengths per layer.
High Density Interconnects Bend in Both Directions
Traditionally, copper has been used for the wiring on most electronic devices. This metal is a great conductor of heat and electricity, and has better mechanical flexibility than aluminum. However, copper can be costly and is susceptible to corrosion and shock hazards. Researchers have developed flexible metallic interconnects using a combination of inherently stretchable materials and structural design. Inherently stretchable materials such as amorphous gold can be shaped into wavy or meandering structures to allow for increased stretchability while maintaining good conductivity.
High-Density Interconnect (HDI) technology represents a pivotal advancement in the realm of electronics and printed circuit boards (PCBs). As the demand for smaller, lighter, and more powerful electronic devices continues to surge, HDI emerges as a solution that not only meets these requirements but also enhances performance, reliability, and flexibility in electronic design.
Conducting polymers are also an option for flexible interconnects. These compounds have high elasticity and tunable flexibility based on the composition. They can be fabricated through solution- or vapor-based processes. However, they are intrinsically unstable over time due to their spontaneous degradation in the environment. To overcome this, active research is underway in both chemical and mechanical approaches.
In addition to being flexible, these new conductive polymer interconnects can be made transparent. They can also withstand dynamic bending, unlike conventional wires. They can also be coated with various polymers to protect them from environmental damage. This makes them a suitable choice for flexible electronic applications such as wearable devices and e-textiles. In addition, the material is biocompatible, reducing the risk of contact allergies or irritation. These advances make the flexible interconnects a promising alternative to traditional copper wiring. They could be used in a wide range of devices, including smartwatches, medical monitors, and automotive sensors. However, further development is necessary before they can be widely deployed.