Electrical properties of polyimide thin films formed by the vapor deposition polymerization method

Thin films of polyimide (PI) were fabricated by a vapor deposition polymerization method (VDPM) and studied for their insulator characteristics in semiconductor devices. Polyamic acid (PAA) thin films fabricated by vapor deposition polymerization (VDP) from PMDA (pyromellitic dianhydride) and DDE (4,4′-diaminodiphenyl ether) were converted to PI thin films by thermal curing. The appropriate curing temperature was 300 °C. From TG-DTA (Thermo Gravimetry-Differential Thermal Analysis), the PI thin films can endure 230 °C for 20 000 h. They exhibited a relative permittivity of 3.9–3.5 and a dissipation loss factor of 0.008 at frequency of 10 kHz in the temperature range from 25 to 200 °C. The resistivity was approximately 3.2×1015 Ωcm and the dielectric breakdown strength was 4.61 MV/cm.