JP2770753B

A plasma processing apparatus comprises a reaction chamber to hold a high-density plasma and having a dielectric plate window, a spiral coil placed outside the reaction chamber and close to the dielectric window, and a lower electrode which holds a wafer to be processed in place and installed in the reaction chamber facing the dielectric plate. A first radio frequency current supply to the coil, a mechanism for varying the distance between the coil and the dielectric plate window, and a second radio frequency voltage supply to the lower electrode is provided. Excellent uniformity of the ion current density of the plasma and hence etching rate is achieved by making the thickness of a central part of the dielectric plate window thicker than its peripheral parts. Also, the uniformity of the plasma and the etching rate is achieved by making the induction field produced by the coil axially symmetrical about the axial center of the reaction chamber. The etching profile and the material etching selectivity are controlled by moving the coil in the axial direction of the coil.