摘要
The present paper investigates the surface roughness generated by reactive ion etching (RIE) on the location between silicon dioxide (SiO<sub>2sub>) micro-pits structures. The micro-pit pattern on polymethyl methacrylate (PMMA) mask was created by an electron beam lithography tool. By using PMMA as a polymer resist mask layer for pattern transfer in RIE process, the carbon (C) content in etching process is increased, which leads to decrease of F/C ratio and causes domination of polymerization reactions. This leads to high surface roughness via self-organized nanostructure features generated on SiO<sub>2sub> surface which was analyzed using atomic force microscopy (AFM) technique. The etching chemistry of CHF<sub>3sub> plasma on PMMA masking layer and SiO<sub>2sub> is analyzed to explain the polymerization. The surface root-mean-square (RMS) roughness below 1 nm was achieved by decreasing the RF power to 150 W and process pressure lower than 10 mTorr.