Investigation on curing process of vapor-deposited polyimide thin films

Using vapor deposition polymerizatioin method, polyimide(PI) thin films were successfully fabricated in different curing conditions. Poly (amic acid) (PAA) thin films at different temperatures and for different retention times at 300 ℃ were analysed by FTIR. The thin films held at 300 ℃ for 3 h were taken off from KBr substrate, and photograghed in interferometry microscope. Also, the thin films were analysed by thermogravimetry (TG) at different heating rates. The results show that the extent of imidization increases with temperature increasing in curing process and retention time increasing at 300 ℃. The thin films can be taken off from KBr for the retention time of 3 h. After curing process surface, the roughness of thin film is good, but Rq is 9.8 nm. The heating rate has a little influence on the ultimate extent of imidization, and low heating rates, 10 ℃/min or even lower, are preferred.