Substrate processing method and substrate processing apparatus

A substrate processing method comprising:

• etching an etching target exposed on a side surface of a recess by supplying alkaline first etching liquid in which inert gas is dissolved to a substrate on which the recess is formed, the recess having a width shorter than a depth of the recess, the recess including the etching target that represents at least one of silicon single crystal, polysilicon and amorphous silicon and that is exposed on at least a portion of an upper portion of the side surface of the recess and at least a portion of a lower portion of the side surface;
• and
• etching the etching target exposed on the side surface of the recess by supplying the substrate with alkaline second etching liquid in which dissolution gas is dissolved and having dissolved oxygen concentration higher than that of the first etching liquid wherein
• the width of the recess before the first etching liquid and the second etching liquid are supplied decreases as a bottom of the recess is approached, and
• in etching the etching target exposed on the side surface of the recess by supplying the substrate with the second etching liquid, an etching amount of the side surface of the recess increases as the bottom of the recess is approached.