Charge Build-Up and Uniformity Control in Magnetically Enhanced Reactive Ion Etching Using a Curved Lateral Magnetic Field

The effectiveness of a curved lateral magnetic field has been examined in magnetically enhanced reactive ion etching (MERIE). It is demonstrated that both charge build-up and etching nonuniformity are suppressed at the same time when the offset angle of dipole magnets is adjusted to 10°. Theoretical analysis of electron flow in the curved lateral magnetic field suggests that the plasma electron multiplication effect along E×B drift motion is compensated by the divergence of the drift motion at the optimum condition, and it results in uniform plasma generation. Although the definite mechanism of charge build-up is still not clear, this study indicates the importance of plasma uniformity in controlling the charge build-up in a MERIE system.