Construction of fluorenyl‐modified low dielectric constant polyimide films with excellent mechanical properties and optical transparency

• Published in: Journal of applied polymer science 2024-04, Vol.141 (15), p.n/a
• Main Authors: Xie, Kang, Li, Zhihua, Zhao, Bo, Guo, Ziteng, Deng, Xingguo
• Format: Article
• Language: English
• Subjects: Copolymerization; Dielectric properties; Electronic components; fluorenyl; low dielectric constant; Mechanical properties; Optical properties; Permittivity; polyimide; Segments; Water absorption
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.55217

In order to meet the requirements of highly integrated and miniaturized electronic components, there is an urgent need for low dielectric materials with high mechanical properties and optical transparency in the field of microelectronics. In this study, a series of novel polyimide films (FPI) containing fluorenyl were prepared, and the effects of the fluorenyl content on the thermal, mechanical, and dielectric properties of the copolymerized films were investigated and discussed. The results demonstrate a significant decrease in the dielectric constant of the FPI films following the introduction of fluorenyl into polyimide (PI) chain segment. The FPI films also exhibited high mechanical properties, including tensile strengths between 92 and 106 MPa and elongation at break in the range of 8.4%–13.0%. Additionally, the introduction of the noncoplanar fluorenyl considerably improved the optical transparency and solubility of the FPI film. It is noteworthy that the FPI‐3 has the best dielectric properties, with a low dielectric constant of 2.61 at 10 MHz and shows low water absorption (0.49%). The results show that we have prepared a novel low dielectric PI material film with excellent mechanical properties and optical transparency by introducing fluorenyl into the PI chain segment. These FPI films with satisfactory properties may be good candidates for dielectric materials for electronic components. A series of novel low dielectric polyimide films with satisfactory properties were successfully synthesized with BAFL, HFPBDA and 6FDA by copolymerization. FPI films show good solubility in organic solvents, a dielectric constant of 2.6–3.0 (10 MHz), a dielectric loss less than 0.009 (10 MHz) and optical transparency (T500 〉81%). FPI films also exhibit high mechanical strength of 92‐106 MPa and elongation at break of 8.4–13.0%.