Low dielectric constant composites using covalent organic framework dispersed terpolyimide

Polyimides are used in various applications, including fuel cells, membranes, and microelectronics, due to their outstanding tensile properties, great thermal stability, low dielectric constant, and chemical inertness. Applications requiring even lower dielectric constants include interlayer dielectrics and tape‐automated bonding. In this study, a covalent organic framework (COF‐1) was synthesized and dispersed in various percentages into a solution of terpoly(amide acid) (TPAA) to produce COF‐1/terpolyimide composites. 3,3′,4,4′‐Oxydiphthalic dianhydride (ODPA), 3,3′,4,4′‐biphenyltetracarboxylicdianhydride (BPDA), and 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) were reacted with 4,4′‐(hexafluoroisopropylidene)bis[(4‐aminophenoxy)benzene] (HFBAPP) or 4,4′‐(hexafluoroisopropylidene) dianiline (6FpDA) to form terpoly(amide acid). In this case, monomers with fluorinated substituents (HFBAPP, 6FpDA, and 6FDA) were utilized to improve free volume. Pores of COF‐1 and gaps between polyimide chains and COF‐1 can be filled with air with a dielectric constant (κ) ~1, lowering the κ value of terpolyimide composites. The κ value of COF‐1/terpolyimide composites decreased as COF‐1 content increased, reaching a minimum of 1.96. Tensile properties decreased slightly with increasing COF‐1 levels. The terpolyimides and their composites were thermally stable up to approximately 520°C. As a result, these polymer composites look promising for use as insulators in microelectronic applications. Highlights Terpolyimide is prepared using fluorinated monomers to improve bulk volume. Incorporated COF‐1 into terpoly(amide acid) to introduce pores/voids and reduce dielectric constant. Developed COF‐1/terpolyimide composites with a low dielectric constant of 1.96. Optimized COF‐1/terpolyimide composites for microelectronic applications. Terpolyimides are prepared using three dianhydrides and two diamines, of which three are fluorinated monomers, so that the bulky fluorinated groups reduce the dielectric constant. COF‐1 was prepared and incorporated into the terpolyimide matrix to further lower the dielectric constant and obtain COF‐1/terpolyimide composites suitable for microelectronic applications.