Measurement of a Three-Dimensional Distribution of Microwave Electric Field in Electron Cyclotron Resonance Plasmas

We have developed an apparatus that can measure the three-dimensional distribution of microwave electric field intensity in electron cyclotron resonance (ECR) plasmas. The reflection edge of the incident microwaves depends on the plasma density in the etching chamber: it is the ECR zone when the electron density (ne) is above 1×1011cm-3and the electrode when neis below 1×1011cm-3. The spatial distribution of the ion saturation current density at the electrode is the same as that of the microwave electric field intensity at the ECR zone. Therefore, in order to obtain uniform ion saturation current density, the intensity of the microwave electric field at the ECR zone must be kept uniform.