New fluorinated polyimides with high heat resistance and low dielectric constants have been synthesized by a two-step procedure. The thermal

mechanical and electrical properties were measured

which indicated that the polyimides with pyridine moieties in the main chain showed both good heat resistance and mechanical properties with initial thermal decomposition temperatures of 545～601℃ in nitrogen and elongation at break of 9％～16％ and tensile strength of 94.2～147.3 MPa．The polyimide films showed also good dielectric properties with dielectric constants of 2.86～2.91 at 1 MHz frequency and breakdown voltage of 150.4～197.3 kV／mm

which was mainly because of the high fluoro-content and large free volume in the molecular structures. All the properties made them great potential candidates for advanced packaging in microelectronic applications．