In this article, we report the surface modification of silicon by an inductively coupled CHF3/O2 plasma treatment for demolding process in nano-imprint lithography. The effects of O2 addition to the CHF3 plasma on the surface polymer were investigated. The Si surface energy remained nearly constant at O2 gas fraction from 0% to 50%, but it increased up to ∼60 mN/m at O2 gas fraction of 60%. In order to examine the relationship between the plasma and surface energy of Si, we attempted to conduct a model-based analysis of the CHF3/O2 plasma. Plasma diagnostics were performed by using a double Langmuir probe. At the same time, the surface analysis of Si was carried out by contact angle measurements and x-ray photoelectron spectroscopy.