abstract |
(57) [Summary] [Configuration] A surface treatment apparatus using plasma, in which a bias power supply for accelerating ions in plasma is intermittently turned on and off, and a deposition gas such as oxygen is used as a halogen gas for etching. [Effect] The mixed halogen gas promotes the etching, and the deposition gas functions to inhibit the etching. The ions accelerated by the bias power supply accelerate the etching reaction. Since the effect of inhibiting the reaction of a deposition gas with respect to a substance having low reactivity with halogen such as an insulator becomes more remarkable, By mixing the deposition gas, the ratio between the etching rates of the semiconductor and the insulator, that is, the selectivity increases. Here, when an off cycle is provided for the bias power supply, only the function of the deposition gas becomes remarkable during the period when the bias power supply is off, that is, during the period when the accelerating ions are not incident on the sample surface, and the selectivity is smaller than that when the bias power supply is continuous Higher. |