Polyimide surface treatment by plasma deposition of organosilcon nano-thin layers

Abstract

Plasma enhanced chemical vapor deposition (PECVD) technique has been used to deposit organosilicon nano-thin layers on polyimide (PI) films substrates from hexamethyldisiloxane (HMDSO) precursor. The nano-thin layers chemical structure was analyzed using Fourier Transform InfraRed (FTIR) spectroscopy and the surface wettability was characterized by contact angle measurements. FTIR analysis showed that the chemical formula of all deposited nano-thin layers were SiOxCyHz-like. Increasing deposition time leads firstly to the increase of the treated PI films hydrophobicity and then to a quasi-saturation of the contact angle value when the discharge time increases beyond 2 min. Ellipsometry measurements showed that the refractive index measured on nano-thin layers elaborated from pure HMDSO with a discharge time of 30 s was found higher than that measured on films deposited with discharge time of about 420 s. Increasing time deposition leads to the decrease in the porosity of the nano-structure coating, leading to denser structure