Patent ID: 7553374

Claim:
A coating treatment apparatus for supplying a coating solution containing a coating film forming component and a solvent to a front face of a square substrate and rotating the substrate about a vertical axis to spread the coating solution into a thin film state over the front face of the substrate, comprising: a substrate holding unit for horizontally holding the substrate; a rotating mechanism for rotating the substrate on said substrate holding unit about the vertical axis; a coating solution nozzle for supplying the coating solution to the front face of the substrate; a gas flow restraining ring provided facing the front face at corner portions of the substrate held on said substrate holding unit, for restraining a gas flow above the substrate; a raising and lowering mechanism for raising and lowering said gas flow restraining ring; and a solvent supply unit for supplying a solvent as a vapor or a mist to a gas flow formed above the front face of the substrate, wherein said solvent supply unit has a solvent flow passage provided in said gas flow restraining ring and a solvent supply port opening in a lower face of said gas flow restraining ring.