This research focuses on ultra smooth surface preparation with root mean square (rms) roughness values R_q < 0.15nm. To reach our goal, we applied low energy (〜2 keV ) Ar+ ion beam sputtering process at different angles of sputtering. After irradiation, the samples were analyzed by AFM to obtain root mean square (rms) roughness values R_q The smoothing techniques were applied on common substrate material such as single crystal Si and Slide glass. Result shows by low energy ion beam with optimum condition, 0.10 nm rms surface roughnesses can be reached.