US Patent 11101146 Substrate processing apparatus

A protective disk is disposed between a spin base and a substrate W and is capable of being raised and lowered between a separated position which is separated downward from the substrate W and a near position which is nearer to the substrate than the separated position. An upper surface of the protective disk has an inner surface which is provided on an inner side of a plurality of holding pins in a radial direction and a flat surface which is provided on an outer side of the inner surface in the radial direction and is provided above the inner surface. The flat surface faces a lower surface of a part on an inner side of an outer circumferential end in the radial direction, in a circumferential edge portion of the substrate.