An apparatus for monitoring a position of a semiconductor process fluid interface in a dispense nozzle includes an extended optical source adapted to provide an optical beam propagating along an optical path. The optical beam is characterized by a path width measured in a first direction aligned with a dispense direction. The apparatus also includes an optical detector coupled to the optical path and adapted to detect at least a portion of the optical beam and a dispense nozzle disposed along the optical path at a location between the extended optical source and the optical detector. The apparatus further includes a nozzle positioning member coupled to the dispense nozzle and adapted to translate the dispense nozzle in the first direction.