A Novel Hydrophobic Polyimide Film with Sag Structure Derived from Multi-Hybrid Strategy.

Polyimide (PI) film with hydrophilic greatly limits their application in the field of microelectronic device packaging. A novel hydrophobic PI film with sag structure and improved mechanical properties is prepared relying on the reaction between anhydride-terminated isocyanate-based polyimide (PIY) containing a seven-membered ring structure and the amino-terminated polyamide acid (PAA) via multi-hybrid strategy, this work named it as hybrid PI film and marked it as PI-PIY-X. PI-PIY-30 showed excellent hydrophobic properties, and the water contact angle could reach to 102°, which is 20% and 55% higher than simply PI film and PIY film, respectively. The water absorption is only 1.02%, with a decrease of 49% and 53% compared with PI and PIY. Due to that the degradation of seven-membered ring and generation of carbon dioxide led to the formation of sag structure, the size of sag structures is ≈16.84 and 534.55 nm for in-plane and out-plane direction, which are observed on surface of PI-PIY-30. Meanwhile, PI-PIY-30 possessed improved mechanical properties, and the tensile strength is 109.08 MPa, with 5% and more than 56% higher than that of pure PI and PIY film, showing greatly application prospects in the field of integrated circuit.

Structural Design and Research Progress of Thermally Conductive Polyimide Film - A Review.

Currently, heat accumulation has seriously affected the stabilities and life of electronic devices. Polyimide (PI) film with high thermal conductivity coefficient (λ) has long been held up as an ideal solution for heat dissipation. Based on the thermal conduction mechanisms and classical thermal conduction models, this review presents design ideas of PI films with microscopically ordered liquid crystalline structures which are of great significance for breaking the limit of λ enhancement and describes the construction principles of thermal conduction network in high-λ filler strengthened PI films. Furthermore, the effects of filler type, thermal conduction paths, and interfacial thermal resistances on thermally conductive behavior of PI film are systematically reviewed. Meanwhile, this paper summarizes the reported research and provides an outlook on the future development of thermally conductive PI films. Finally, it is expected that this review will give some guidance to future studies in thermally conductive PI film.