US Patent 7591902 Recirculation and reuse of dummy dispensed resist

The present invention provides a system and methodology for dummy-dispensing resist though a dispense head while mitigating waste associated with the dummy-dispense process. The dummy dispensed resist is returned to a reservoir from which it was taken. Between substrate applications, the dispense head can be positioned to dispense resist into a return line. The flow of resist from the dispense head keeps resist from drying at the dispense head. By funneling the dummy-dispensed resist into a return line with low volume, for example, waste from the dummy-dispensing process can be mitigated.