Development of A Low k Thermosetting Resin Based on 5,5’6,6’-Tetrahydroxy-3,3,3’,3’-Tetramethylspirobisindane with Decafluorobiphenyl Having Ethynyl Terminals

Abstract

5,5’6,6’-Tetrahydroxy-3,3,3’,3’-Tetramethylspirobisindane (TTSBI) was reacted with 4 mol-equiv of decafluorobiphenyl (DFBP), followed by the reaction with 3-hydroxyphenylacetylene (3HPA) / 4-amylphenol (4AP) to give novel low k thermosetting resins. These resins exhibited an exothermic peak due to the thermosetting reaction around 170-206 ℃, and the yellowish transparent films were successfully prepared by hot-press method. The functionalization with the ethynyl group was around 70% at 200 ℃ for 2 h, and 70-99% at 230 ℃ for 2 h. This film did not show a glass transition temperature when measured by DSC and TMA up to 300 ℃. The thermoset resins were soluble in ordinal organic solvents, but the cured film was insoluble in all solvents. The refractive index at 594 nm was 1.547-1.562, and the optical permittivity was 2.39-2.44. The relative permittivity and dielectric loss tangent measured by the cavity resonance method were 2.37 to 2.40 and 0.0019 to 0.0035 at 20 GHz.