A substrate processing method includes providing a substrate into a chamber, the substrate including a silicon oxide film and a mask of an organic film on the silicon oxide film, etching the silicon oxide film with a first plasma generated from a first process gas, the first process gas including a fluorocarbon gas and a hydrogen-containing gas, and further etching the silicon oxide film with a second plasma generated from a second process gas, the second process gas including a fluorocarbon gas. A flow rate of the hydrogen-containing gas included in the first process gas is less than a flow rate of the fluorocarbon gas included in the first process gas.