Method and apparatus for multiple recirculation and filtration cycles per dispense in a photoresist dispense system

A method for dispensing a liquid onto a substrate using an apparatus comprising a reservoir for storing the liquid to be dispensed;

• a filter comprising an inlet and an outlet, the filter inlet in fluidic communication with the reservoir via a first valve;
• a dosing pump comprising an inlet, a first outlet, and a second outlet, the dosing pump inlet in fluidic communication with the reservoir and the dosing pump second outlet in fluidic communication with the filter inlet via a second valve;
• and a dispense nozzle in fluidic communication with the dosing pump first outlet;
• the method comprising:
• dispensing the liquid through the dispense nozzle onto the substrate;
• and
• alternately flowing the liquid from the dosing pump via the second valve to the filter to filter the liquid while maintaining a positive pressure at the filter inlet and flowing the liquid from the reservoir via the filter and trap reservoir to reload the dosing pump while filtering the liquid;
• wherein the liquid is alternately flowed from the dosing pump and from the reservoir a plurality of times per dispense.