Polyimide composites with optimized low dielectric constant and high thermal conductivity for electronic packaging

Polyimide is widely used high temperature polymer in electronic packaging. However, its inherent high dielectric constant and low thermal conductivity can not meet the demands of operational efficiency and long-term stability for high-frequency and high-voltage power devices. Therefore, this study prepared the BN/PEG/PI composite by using hollow glass microspheres (HGM) and thermally unstable polyethylene glycol (PEG) as pore-forming agents to decrease the dielectric constant, and c-BN and h-BN particles as high-thermal-conductive fillers. The results indicated that PEG is more conducive to improving the PI dielectric performance at both low and high frequencies, with the lowest dielectric constant of 2.81 and dielectric loss of 0.009 at 10⁶ Hz. Compared to c-BN particles, h-BN doped BN/PEG/PI composite has better comprehensive performance. When PEG content is 30 wt% and h-BN filler content is 10 wt%, the 10h-BN/30PEG/PI composite exhibits outstanding in-plane thermal conductivity of 0.81 W·m⁻¹·K⁻¹, low dielectric constant 3.52, and dielectric loss 0.009 at 10⁶ Hz. The BN/PEG/PI porous composite holds significant application potential in electronic packaging.