Synthesis and applications of low dielectric polyimide

With the advent of the 5 G era, advanced packaging applications such as wafer-level fan-out packaging have emerged thanks to efforts to reduce signal loss and increase signal transmission rates. As one of the key materials employed in telecommunication devices, the interlayer dielectric material directly affects signal transmission and device reliability. Among them, polyimide (PI) has become an important interlayer dielectric material because of its excellent comprehensive properties. However, in order to meet the needs high-frequency and high-speed circuits for 5 G networks, it will be necessary to further reduce the dielectric constant and dielectric loss of PI. PI is widely used as a flexible dielectric material due to its excellent electrical insulation properties (dielectric constant ≈ 3.0–4.0, dielectric loss ≈ 0.02), mechanical properties, and thermal resistance. However, further reduction in the dielectric constant will be needed in order for PI-based materials to better meet the current high integration development needs of the microelectronics industry. This article starts from strategies to prepare low dielectric PI that have been developed in the last decade, based on a more systematic and inductive analysis, and prospects the development potential of low dielectric PI.