Patent ID: 8769842

Claim:
A substrate drying method of supplying a substrate rotating in a horizontal plane with a rinse agent flow and a drying gas flow while the rinse agent flow and the drying gas flow are moved from the center side toward an outer periphery side of the rotating substrate, the drying gas flow being able to contain IPA, said method comprising: drying a center area of the substrate, the center area being a range where a rotation center of the substrate exists in a collision range of the drying gas flow with the substrate; and drying an outer periphery area existing outside of the center area of the substrate, wherein the outer periphery area is a range outside of an inner periphery area as well as inside of a peripheral end area, the inner periphery area being a range outside of the center area and within a virtual circle centered at the rotation center and having a radius of one half of the radius of the substrate, the peripheral end area being outside of a trajectory in which a position of the drying gas flow is rotated around the rotation center in a state that the rinse agent flow and the drying gas flow are moved in a radial direction of the substrate and the rinse agent flow and the drying gas flow reach a position where supply of the rinse agent flow to the substrate is stopped, and wherein an IPA concentration of the IPA contained in the drying gas flow is maintained at less than 2 mol % during said drying of the center area, and at 2 mol % or more in said drying of the outer periphery area.