Substrate processing apparatus and method of detecting indentation formed in substrate

A method of detecting comprising:

• holding a substrate on a surface of a substrate stage;
• injecting a fluid to a circumferential edge portion of a top surface of the substrate using a fluid injection nozzle having a tip directed vertically downward toward the surface of the substrate stage while rotating the substrate and the substrate stage using a rotation motor;
• measuring a physical quantity which is pressure or a flow rate of the fluid;
• and
• detecting a position of an indentation formed in a circumferential edge portion of the substrate based on a change in physical quantity;
• wherein a direction of the tip of the fluid injection nozzle is perpendicular to the holding surface of the stage;
• wherein a first distance is between an axial center of the substrate stage and a centerline of the fluid injection nozzle and the first distance is smaller than a radius of the substrate.

A method of detecting comprising:

• holding a substrate on a substrate stage;
• injecting a fluid to a circumferential edge portion of the substrate while rotating the substrate and the substrate stage;
• measuring a physical quantity which is pressure or a flow rate of the fluid;
• and
• detecting a position of an indentation formed in a circumferential edge portion of the substrate based on a change in physical quantity,
• wherein the injecting the fluid to the circumferential edge portion of the substrate while rotating the substrate and the substrate stage includes injecting the fluid to the circumferential edge portion of the substrate while rotating the substrate and the substrate stage in a first direction and a second direction opposite to the first direction, and
• the detecting the position of the indentation based on the change in physical quantity includes detecting a first position of the indentation formed in the circumferential edge portion of the substrate based on the change in physical quantity when the substrate and the substrate stage are rotated in the first direction, detecting a second position of the indentation based on the change in physical quantity when the substrate and the substrate stage are rotated in the second direction, and determining the position of the indentation which is an average of the first position and the second position.