Effectiveness of NH3 plasma treatment in preventing wet stripper damage to low-k hydrogen silsesquioxane (HSQ)

Abstract

Wet stripper is commonly used to remove photoresist in IC integration processing. However, the high alkalinity of the wet stripper solution often leads to the hydrolysis of hydrogen silsesquioxane (HSQ) film and induces water uptake. As a result, both the leakage current and dielectric constant of HSQ increase. In this study, NH3 plasma treatment was applied to the HSQ film to form a thin nitrogen-containing layer on the HSQ surface and prevents the hydrolysis of HSQ during photoresist stripping. Dielectric degradation can be prevented by NH3 plasma treatment.