NOVELTY - The device has a substrate holding portion for holding a substrate (W) i.e. semiconductor wafer, in a horizontal posture. A rotating portion rotates the substrate held in the holding portion in a horizontal plane. A heating portion injects heating steam (51) into a central part of a back/lower surface (S2) of the substrate to entirely heat the substrate. A peripheral edge processing portion (122) supplies processing liquid (52) from the heating portion to a peripheral edge part (S3) of the substrate, which is heated by the heating portion for carrying out a chemical treatment for the part.    USE - Substrate processing device for carrying out chemical treatment i.e. bevel etching, for an upper surface peripheral edge part of a substrate i.e. semiconductor wafer, in a semiconductor device by using processing liquid i.e. etchant. Uses include but are not limited to an optical disk, magnetic disk, magneto-optical disk, photomask and a solar cell.    ADVANTAGE - The heating steam is injected to a central part of the lower surface of the substrate such that the substrate is entirely heated, and the processing liquid is supplied to the peripheral edge part from the heating portion to carry out the chemical treatment for the peripheral edge part to enhance reactivity of the processing liquid in the peripheral edge part even if an amount of the processing liquid to be supplied is small by sufficiently heating the peripheral edge part, so that usefulness of the device is not lost, thus reducing chemical treating width, while suppressing deterioration in uniformity of the chemical treating width i.e. etching width, and chemical treating efficiency i.e. etching rate, and controlling the etching width with high precision irrespective of rotating speed of the substrate if the processing liquid is supplied from the heating portion to a desirable region having small width at the substrate end side in the peripheral edge part, and suppressing wraparound of water droplet onto an upper surface of the substrate even if the water droplet is generated by condensation of the steam over the lower surface of the substrate to prevent deterioration in a non-processed region from being caused by adhering the water droplet to the non-processed region on the upper surface of the substrate, and hence increasing yield of the device and reducing trouble in the device.    DETAILED DESCRIPTION - The holding portion is a spin chuck. The rotating portion is a chuck rotating portion. The heating portion is a steam injection nozzle. The peripheral edge processing portion is a processing liquid discharging portion. The peripheral edge part is an upper surface peripheral edge part. An INDEPENDENT CLAIM is also included for a substrate processing method for carrying out chemical treatment for a substrate by using processing liquid.    DESCRIPTION OF DRAWING(S) - The drawing shows a side view of a nozzle unit.    Back/lower surface of substrate (S2)    Peripheral edge part (S3)    Substrate (W)    Heating steam (51)    Processing liquid (52)    Peripheral edge processing portion (122)