Patent ID: 7779777

Claim:
A substrate-processing apparatus comprising: a sample table which mounts thereon a to-be-processed substrate; a first line which supplies a chemical solution; a second line which supplies a cleaning liquid; a first three-way valve connected to the first and second lines and configured to select one of the first and second lines, the first three-way valve selecting the first line when the substrate is coated with the chemical solution, selecting the second line after the chemical solution is supplied, and selecting the first line before the chemical solution is again supplied; a filter provided across the first line upstream of the first three-way valve, and configured to eliminate a foreign material from the chemical solution; a nozzle provided downstream of the first three-way valve and configured to discharge the chemical solution or the cleaning liquid when the first or second line is selected via the first three-way valve; and a second three-way valve interposed between the first three-way valve and the nozzle and configured to switch supply of the chemical solution or the cleaning liquid to a nozzle side or to a third line side, the second three-way valve switching the supply to the nozzle side when the chemical solution is supplied onto the substrate, thereby causing the nozzle to discharge the chemical solution onto the substrate, the second three-way valve switching the supply to the nozzle side after the chemical solution is supplied, thereby filling a portion ranging from the first three-way valve to the nozzle with the cleaning liquid, the second three-way valve switching the supply to the third line side before the chemical solution is again supplied, thereby discharging, through a third line, the chemical solution contained in a portion ranging from the filter to the first three-way valve.