Preparation and characterization of low-κ co-polyimide films

The emergence of 5G communication technology has heightened the demand for high-performance electronic substrate materials with low dielectric constants (K) and low dielectric loss factors (D). Traditional polyimide materials, while valued for their excellent thermostability and mechanical strength, often fall short in meeting the stringent requirements for high-frequency integrated circuits. This article presents a novel approach to synthesizing co-polyimide films with ultra-low K values by adjusting the molar ratio of 6FDA/PMDA. The study employs positron annihilation lifetime spectroscopy (PALS) to investigate the correlation between microstructure and dielectric properties, revealing significant insights into how molecular structure modifications impact the films' performance. The findings demonstrate a marked reduction in dielectric constant and breakdown electric field with increasing 6FDA content, attributed to the steric hindrance effect of bulky -CF3 groups. Additionally, the incorporation of -CF3 groups leads to a decrease in mechanical properties, highlighting the trade-offs in optimizing dielectric and mechanical characteristics. The article provides a detailed analysis of the thermal, optical, and mechanical properties of the synthesized films, offering a comprehensive understanding of the structure-property relationships in co-polyimide systems. This research paves the way for developing advanced dielectric materials through molecular architecture engineering, addressing the critical needs of the high-frequency electronics industry.