Korean Journal of Materials Research ISSN:1225-0562(Print) 2287-7258(Online) 한국재료학회지

To improve the etch rate of Si₃N₄ thin film, H₂SiF₆ is added to increase etching rate by more than two times. SiO₃H₂ is gradually added to obtain a selectivity of 170: 1 at 600 ppm. Moreover, when SiO₃H₂ is added, the etching rate of the SiO₂ thin film increases in proportion to the radius of the wafer. In Si₃N₄ thin film, there is no difference in the etching rate according to the position. However, in the SiO₂ thin film, the etching rate increases in proportion to the radius. At the center of the wafer, the re-growth phenomenon is confirmed at a specific concentration or above. The difference in etch rates of SiO₂ thin films and the reason for regrowth at these positions are interpreted as the result of the flow rate of the chemical solution replaced with fresh solution.