Influence of CF_4 plasma treatment on dielectric properties of polyimide film
The polyimide film used in printed substrate is treated by CF4 plasma activation, and fluoric group is introduced to the surface of polyimide film. The results of the experiment are verified by measuring the contact angle and X-ray photoelectron spectroscopy. The influence of different conditions on the dielectric constant and dielectric loss of polyimide film is studied by changing the power and reaction time of plasma activation. The results show that with treatment power and treatment time up, the dielectric constant and dielectric loss obviously drops in low frequency area(1~100 Hz). At the optimized condition, the average dielectric constant changes from 2. 7 to 1. 9(1~100 Hz), and the average dielectric loss changes from 0. 145 to 0. 06(1~100 Hz).