Substrate processing apparatus and method of processing substrate

A substrate processing apparatus which processes a substrate with a processing liquid, comprising:

• a substrate holding unit, having a spin base to hold the substrate;
• a blocking member, having a substrate facing surface which faces an upper surface of the substrate held by the substrate holding unit and having a diameter larger than the spin base;
• a blocking member lifting unit, raising and lowering the blocking member between a blocking position and a retreat position that is retreated upward from the blocking position, wherein at the blocking position a space between the substrate facing surface and the upper surface is blocked from a lateral side on the upper surface and at the retreat position the space is not blocked from the lateral side on the upper surface;
• and
• a plurality of guards, including an inner side guard surrounding a periphery of the substrate holding unit and an outer side guard surrounding a periphery of the inner side guard to capture a processing liquid discharged from between the substrate and the blocking member, where the inner side guard and the outer side guard are cylindrical,
• wherein an inner circumferential end of the outer side guard is positioned on an outer side in a radial direction of an inner circumferential end of the inner side guard,
• wherein the blocking member includes a disc portion and a cylindrical portion that extends downward from an outer circumferential portion of the disc portion,
• wherein a diameter of a circumference defined by the inner circumferential end of the outer side guard is larger than an outer diameter of the cylindrical portion of the blocking member, and a diameter of a circumference defined by the inner circumferential end of the inner side guard is equal to or smaller than the outer diameter of the cylindrical portion of the blocking member.