NOVELTY - The apparatus (1) has an ejection head (31) arranged inside a cup part (22) and above a substrate holding part (21) and for ejecting a processing liquid toward a substrate (9) from an outlet provided in an ejection surface. A supply part movement mechanism (35) moves the ejection head from a position above the substrate holding part to standby position outside the cup part. A reservoir is arranged outside the cup part to retain an immersion liquid in which the surface of the ejection head is located at the standby position. A liquid removing part removes the immersion liquid from the surface.    USE - Substrate processing apparatus i.e. single-wafer processing apparatus, for processing a substrate i.e. semiconductor substrate. Can also be used for optical disk substrate, magnetic disk substrate, magneto-optical disk substrate, photomask substrate, ceramic substrate, solar cell substrate and glass substrate utilized in display device e.g. LCD, plasma display and field emission display.    ADVANTAGE - The apparatus prevents drying of outlets to prevent liquid dripping during processing. The immersion liquid enters the outlets during standby mode of the ejection head, thus eliminating the need for an operation such as flushing, for discharging the immersion liquid in the outlets when the use of the ejection head is resumed. The ejection of the processing liquid from the outlets of the ejection head is stopped before the ejection surface is separated from the immersion liquid, thus allowing the liquids on the ejection surface to more easily drop off, and hence reducing the amount of the immersion liquid remaining on the ejection surface.    DETAILED DESCRIPTION - The immersion liquid is pure water e.g. deionized water, carbonated water, and mixture of aqueous ammonia and hydrogen peroxide solution. The substrate is a semiconductor substrate. An INDEPENDENT CLAIM is also included for a standby method for an ejection head of a substrate processing apparatus.    DESCRIPTION OF DRAWING(S) - The drawing shows a front view of a substrate processing apparatus.    Substrate processing apparatus (1)    Substrate (9)    Substrate holding part (21)    Cup part (22)    Ejection head (31)    Supply part movement mechanism (35)