Method and system for resist defect reduction

A method, comprising:

• introducing a resist liquid into a first tank in a resist filtration system, the resist filtration system comprising a filter-containing pipeline connecting the first tank to a second tank;
• flowing the resist liquid from the first tank to the second tank through a filter-containing pipeline, wherein when a filtered portion of the resist liquid reaches the second tank, the filtered portion remains in the second tank while another portion of the resist liquid continues to flow from the first tank to the second tank;
• and
• after a liquid level in the first tank drops below a predetermined threshold, flowing the filtered portion of the resist liquid from the second tank back to the first tank.

A resist filtration system, comprising:

• a first tank;
• at least one second tank;
• a first pipeline downstream of the first tank and upstream of the second tank;
• a second pipeline downstream of the second tank and upstream of the first tank;
• one or more first filters in the first pipeline;
• a first pump in fluid communication with the first pipeline to allow a resist liquid flow from the first tank to the second tank;
• a second pump in fluid communication with the second pipeline to allow a resist liquid flow from the second tank to the first tank;
• and
• a controller operable to asynchronously activate the first pump and the second pump, wherein the asynchronous activation comprises activating the first pump while remains the second pump deactivated, and activating the second pump after a liquid level in the first tank drops below a predetermined threshold.