Electrostatic Neutralization Characteristics of an AC‐Corona‐Discharge‐Type Ionizer in Mixed N₂‐O₂, N₂‐SF₆ Atmosphere

Abstract

SUMMARY We are developing an electrostatic neutralizer operating in an atmosphere without oxygen for the organic electronics fabrication industry. As a part of the study, we investigated ion generation and neutralization characteristics of an ac‐corona‐discharge‐type ionizer in different atmospheric gases such as ambient air, pure nitrogen, and mixed N2‐O2 and N2‐SF6 gases, with changing the partial pressure of O2 and SF6, respectively. The I–V characteristic of the emitter shows that the negative current in N2 gas is significantly greater than the positive one; thus, the product final voltage VPF gives a significant deviation to a negative value (about –2 kV). However, by introducing SF6 gas by 0.01%, VPF reduces to about 0 V as that in ambient air. The amount of SF6 needed to improve the ion balance is three orders of magnitude smaller than that of O2, due to higher electronic affinity that a SF6 molecule has.

Static Elimination Performance of a Corona Ionizer in Nitrogen-Based Electronegative Gases

“…With these backgrounds, the authors conducted a study on ion generation and static elimination characteristics of an AC corona ionizer in the mixed N 2 -SF 6 gas with changing the partial pressure ratio of SF 6 [8]. As is well known, SF 6 is an electronegative gas that has been used commercially as the insulating gas of electrical power systems and as the plasma etching gas in semiconductor manufacturing processes.…”