Microwave ECR Chamber

In the Hitachi ECR Chamber, a DC current flows through the electromagnetic solenoid coils generating a strong static magnetic field in the etch chamber. The etch chamber is tuned so the magnetic field intensity decreases as it approaches the wafer surface. Microwaves at 2.45GHz are introduced into the chamber resonance cavity through a wave guide producing a dynamic electric field that is perpendicular to the magnetic field. Process gases are introduced at low pressure through a shower plate. These gases generate the electrons and ions of the plasma that diffuses from the high magnetic field intensity of the ECR zone to the low magnetic field intensity at the wafer surface. Hitachi’s etch systems also apply a separate RF bias to the wafer electrode to independently control ion energy at the wafer surface.