Abstract: In order to improve the etching rate and reduce the roughness of the etched surface, the effects of gas ratio, RF power, total gas flow rate, duty cycle of pulse bias power supply and incident angle on etching rate and roughness in the process of SF₆/Ar ion beam etching silicon dioxide were studied by using pulse extraction single gate reactive ion source. The results show that the influence of RF power on etching rate and roughness is different under different conditions. The higher the proportion of SF₆ gas, the higher the etching rate. As the total gas flow increases, the etching rate gradually increases, and the roughness changes little. When the duty cycle of the pulse bias power supply is small, the etching rate is relatively stable and the roughness is relatively small. When the incident angle is not more than 60°, the etching rate changes little, and the root mean square roughness changes greatly. When the incident angle is greater than 60°, the etching rate and root mean square roughness decrease significantly.