Stabilization of CF4 plasma treated carbon surface by heat treated during and after plasma treatment has been successfully achieved. Carbon surface was altered to hydrophobic by adsorbed fluorine (F) atoms during CF4 plasma treatment. F atoms desorbed from carbon surface after plasma treatment caused time dependent change of the carbon surface properties. The change was stopped by heating during plasma treatment because simultaneous heat and plasma treatment make the F atom bonds stable. However, heat treatment may diminish the merits of the plasma treatment such as low-temperature and damage-free treatment. Heat treatment during and after plasma treatment enabled to stabilize the F atom bonds of the carbon surface in spite of the lower temperature and to reduce the surface damage. Surfaces properties unchanged over 70 days and the degree of damage was almost the same as the one on the surface with plasma treatment only.