Saba Jawad Kadhem it is impossible to answer your question before you describe what do you mean "improve"? What film parameters you like to modify, improve? Color, luminescence intensity, hardness, conductivity, etc.? Give more details of your project challenge.
Dr. Valeriy Sterligov has rightly asked you regarding which property/parameter requires the improvement. You may kindly look at https://en.wikipedia.org/wiki/Plasma_etching.
The Oxygen Plasma make important roll on Thin polymer material for surface activation as well surface coating (on 0.0001mbar generated by Diffusion Pump)