Multi-Coil System for Electron Cyclotron Resonance Plasma Generation

The authors have developed a new multi-coil system for electron cyclotron resonace (ECR) plasma generation. The features of this multi-coil system are precise magnetic field control and the capability of achieving compatibiliry with low magnetic field gradient and high magnetic field uniformity. A low gradient and high uniformity of magnetic field in the ECR region contribute to highly dense and highly uniform plasma generation. Therefore, etching characteristic improvement is expected. As compared with the conventional two-coil system, the present multi-coil system achieved improvement of magnetic field uniformity of more than 60% at a low magnetic field gradient less than 20 G/cm, ion currentdensity of more than 25%, and ion currentdensity uniformity of about 75% in Ar plasma.