Optimally stable electron cyclotron resonance plasma generation and essential points for compact plasma source

This study examines the strong dependence of electron cyclotron resonance (ECR) plasma generation on the microwave conditions and the magnetic field profiles in the ECR plasma. When an introduced microwave frequency oscillates and has a large ripple, the ECR plasma around the ECR region vibrates and regularly turns on and off. The microwave oscillation and the microwave ripple must be eliminated to prevent poor etching anisotropy. Moreover, the nonuniform plasma causes disturbed ion motions due to magnetohydrodynamic (MHD) plasma instability. It is found that uniform and high-density ECR plasma is generated by optimizing the waveguide, the location of the ECR region and the magnetic field profiles for precise ULSI patterning. Based on these results, we determine the essential features for realizing a compact ECR plasma source.