Substrate processing method, and substrate processing device

A substrate processing method comprising:

• a chemical liquid step of supplying a chemical liquid to an upper surface of a substrate held by a substrate holding unit in a horizontal posture;
• and
• a puddle rinse step of rinsing away the chemical liquid supplied in the chemical liquid supplying step and adhering to the upper surface of the substrate by holding a liquid film of a puddled rinse liquid on the upper surface of the substrate while maintaining a rotation speed of the substrate at a fixed puddle speed;
• the chemical liquid step including:
• a chemical liquid covering step of supplying the chemical liquid to the substrate held by the substrate holding unit while rotating the substrate at a rotation speed so as to cover the upper surface of the substrate with a liquid film of the chemical liquid,
• immediately followed by a chemical liquid puddle step of puddling the chemical liquid and holding a liquid film of the puddled chemical liquid on the upper surface of the substrate, by decreasing the rotation speed of the substrate to the fixed puddle speed and maintaining the rotation speed of the substrate at the fixed puddle speed after a completion of the decrease of the rotation speed, the puddle rinse step being performed immediately subsequent to a finish of the chemical liquid puddle step, the supply of the chemical liquid being stopped by a beginning of the puddle rinse step;
• the puddle rinse step including a step of supplying a rinse liquid different from the chemical liquid the upper surface of the substrate and then replacing the liquid film of the chemical liquid held on the upper surface of the substrate with the rinse liquid,
• wherein during a period of time from the completion of the decrease of the rotation speed in the chemical liquid puddle step until an end of the puddle rinse step, the rotation speed of the substrate is maintained at the fixed puddle speed, and the fixed puddle speed is a zero speed or a speed lower than the rotation speed of the substrate in the chemical liquid covering step and
• the fixed puddle speed is predetermined such that the upper surface of the substrate continues being entirely covered with the liquid film of the puddled chemical liquid and/or the rinse liquid throughout the period, whereby the upper surface of the substrate avoids being exposed throughout the period.