Patent ID: 8865483

Claim:
A substrate processing method comprising: holding a substrate by a substrate holding member; determining a holding state of the substrate held by the substrate holding member in which detection light is radiated from a light projector and received by a light receiver, and the holding state of the substrate is determined based on whether or not the detection light is received by the light receiver or on the light receiving by the light receiver; and performing a processing on the substrate by supplying a processing fluid to the substrate held by the substrate holding member after it is determined that the substrate is properly held by the substrate holding member, wherein the light projector and the light receiver are positioned such that a light path of the detection light from the projector toward the light receiver passes a region where the substrate exists when the substrate is held by the substrate holding member and passes the substrate surrounding member, and the detection light radiated from the light projector has a wavelength which penetrates the substrate surrounding member but does not penetrate the substrate.