A new look at the financial impact of air ionization

The use of air ionization in semiconductor manufacturing has been shown to reduce micro-contamination [1,2,3,4] and improve process yield >0.2%. However, when used within a mini-environment the need for periodic cleaning and calibration results in downtime and tool unavailability. For some processes in mini-environments, this loss exceeds the yield enhancements. This paper estimates the effective yield loss at 0.58% for processes requiring considerable ionizer maintenance and recommends the use of non-corona ionizers for those processes known to exhibit a high rate of emitter point debris collection.