Patent attributes
In the vicinity of a rim portion of a spin base 5, a plurality of supports 7 which abut on a bottom rim portion of a substrate W and support the substrate W are formed projecting toward above from the spin base 5. The substrate W is supported horizontally by the plurality of supports 7, with a predetermined distance ensured from the spin base 5 which opposes the bottom surface of the substrate W. Into the space which is created between the top surface of the substrate W and an opposing surface 9a of an atmosphere blocker plate 9, inert gas is ejected from a plurality of gas ejection outlets 9b which are formed in the opposing surface 9a. The inert gas thus supplied to the top surface of the substrate W presses the substrate W against the supports 7 and the substrate W is held at the spin base 5.