Substrate processing method and substrate processing device

A substrate processing method comprising:

• a substrate holding step of causing a substrate holding unit to hold a substrate in a horizontal orientation, the substrate having one major surface and the other major surface, the one major surface being a non-device-formation surface in which no device is formed, the other major surface being a device formation surface in which a device is formed;
• a substrate rotating step of rotating the substrate about a predetermined rotation axis that passes through a center portion of the one major surface of the substrate;
• an ozone-containing hydrofluoric acid solution spouting step of spouting an ozone-containing hydrofluoric acid solution containing ozone dissolved therein from a nozzle toward the center portion of the one major surface of the substrate held by the substrate holding unit at a spouting flow rate of not lower than 0.8 L/min in the substrate rotating step, the ozone-containing hydrofluoric acid solution having a hydrofluoric acid concentration of not lower than 0.093 wt. % and not higher than 0.140 wt. %, and having an ozone concentration of not lower than 22.5 ppm and not higher than 67.2 ppm;
• and
• a brush-cleaning step of cleaning the one major surface of the substrate by bringing a cleaning brush into abutment against the one major surface of the substrate, the brush-cleaning step being performed after the ozone-containing hydrofluoric acid solution spouting step or in parallel with the ozone-containing hydrofluoric acid solution spouting step.