Progress in low dielectric polyimide film – A review

Polyimide (PI) possesses excellent thermal stability, mechanical, chemical stability, and electrical insulation properties. Thus, PI has become the most important polymer as interlayer insulating materials in microelectronics industry. However, with the development of integrated circuits for the continuously decreasing component size and increasing device integration, the high dielectric constant (k) and dielectric loss (Df) of ordinary aromatic PI film has been unable to meet the demand of microelectronics industry. Therefore, many efforts have been exerted to reduce k and Df of PI film. This article reviews the relative and systematic works about low-k PI film, and mainly summarizes the recent research progresses in intrinsic and porous low-k PI film. The Df of these low-k PI films is briefly introduced, and the influencing factors of Df are analyzed. On this basis, this review also summarizes the advantages and disadvantages of different route to generate low-k PI film, and furtherly compares the dielectric properties, thermal stability, and mechanical properties of different low-k PI film. Finally, this paper aims to gain a deeper understanding about low-k PI film and provide a reference for the future development of low-k PI film. The comprehensive and in-depth insights provide a sufficient basic theories and research results reference to guide the future development and optimization of PI films possessing excellent mechanical, flexible, and electrical insulation properties.