Noise reduction of corona discharge air ionizer

A new structure of a corona discharge air ionizer was proposed in order to reduce its noise generation aiming to use it in ULSI inspection process. The ionizer has an upward emitter and a grounded grid above the emitter to confine electric field generated by high operation voltage. The air ionizer with the proposed structure drastically reduced the noise generation compared to air ionizer with conventional structure, and also showed good charge elimination characteristics. The proposed air ionizer is expected to be utilized in a ULSI manufacturing process especially in the inspection process that requires low noise environment.