Plasma induced damage of ultra low-k (ULK) dielectrics is a common phenomenon in BEOL interconnects. The damage leads to an increase in k-value, which raises the RC delay, leading to increased power consumption and cross talk noise. Therefore, diverse repair and post etch treatments (PET) have been proposed to restore or reduce the ULK damage. However, current repair processes are usually based on non-plasma silylation, which suffers from limited chemistry diffusion into the ULK. Moreover, the conventional PET based on anisotropic plasma results in bottom vs. sidewall inhomogeneities of the structures (e.g. via and trench). To reduce these drawbacks, an organosilane downstream -plasma (DSP) was applied. This new application resulted in an increased resistance to ULK removal by fluorinated wet clean chemistries, preserving the ULK hydrophobicity, keeping its carbon content relatively high. The effective RC measured on 28 nm node patterned wafers treated with a DSP PET remains nevertheless comparable to the process of record (POR).