PURPOSE: To reduce foam formed through swelling of a resist at a peripheral part of a substrate and to restrain the resist from being stripped off by a method wherein, before the substrate is coated with the resist and when a vapor for hydrophobic treatment use is supplied and applied to its one main face, the peripheral part of the substrate is hidden by a mask.

CONSTITUTION: A wafer 1 composed of a substrate to be treated, e.g. a silicon single-crystal substrate or the like, is provided with a ring-shaped mask 10 at the upper part in a peripheral part. Said wafer 1 is carried into a treatment chamber 9 and is set on a suction plate 2 by a vacuum suction operation. Then, a valve 8 is opened; nitrogen gas is supplied through a gas pipe 6 for bubbling use. At this time, a tip part of the gas pipe 6 is inserted into a hexamethyldisilazane HMDS liquid 4; the HMDS liquid 4 is gasified by a bubbling operation and is pressure-fed through a pipe 7; it is sprayed into the treatment chamber 9 from a spray port of a nozzle plate 3; the wafer 1 is treated for a prescribed time. At this time, an HMDS vapor is not applied to a peripheral part of the wafer 1 because of the mask 10. After that, a resist is coated and a pattern is formed.