2-D measurement of charged particles diffusing from a double DC corona discharge ionizer

Spatial distributions of charged particles diffusing from a double dc corona discharge ionizer operated in air and nitrogen atmospheres are 2-D measured. It is experimentally demonstrated that static electricity on a silicon wafer downstream side of the ionizer is eliminated only in the area where the local net charge flux becomes zero. The 2-D profiles of the local net ion current clearly show that the spatial profile of the local net ion current can be controlled by a balance between the positive and negative discharge voltages. Hence, it is demonstrated that the balance can yield the control of the charge elimination area.