A substrate processing apparatus according to the present disclosure includes: a nozzle that ejects a processing liquid to a wafer; a force-feeding unit that force-feeds the processing liquid to the nozzle side; a liquid feeding pipeline that includes first and second valves and guides the processing liquid from the force-feeding unit to the nozzle; and a controller. The controller is configured to perform opening the first valve in a state where the second valve is closed and a pressure between the first and second valves is higher than a pressure between the force-feeding unit and the first valve, controlling the force-feeding unit to increase the pressure between the first and second valves that has been decreased by the opening of the first valve, and opening the second valve after the pressure between the first and second valves is decreased by the opening of the first valve.

A metal plate used for manufacturing a deposition mask has a thickness of equal to or less than 30 m. An average cross-sectional area of the crystals grains on a cross section of the metal plate is from 0.5 m.sup.2 to 50 m.sup.2. The average cross-sectional area of crystal grains is calculated by analyzing measurement results obtained by an EBSD method, the measuring results being analyzed by an area method under conditions where a portion with a difference in crystal orientation of 5 degrees or more is recognized as a crystal grain boundary.

A metal plate used for manufacturing a deposition mask has a thickness of equal to or less than 30 m. An average cross-sectional area of the crystals grains on a cross section of the metal plate is from 0.5 m.sup.2 to 50 m.sup.2. The average cross-sectional area of crystal grains is calculated by analyzing measurement results obtained by an EBSD method, the measuring results being analyzed by an area method under conditions where a portion with a difference in crystal orientation of 5 degrees or more is recognized as a crystal grain boundary.