JPS6444019A - Dry etching apparatus - Google Patents

Abstract

PURPOSE:To obtain a dry etching apparatus which reduces irregularity of an etching velocity by forming a discharge tube in a concentric double structure, and radiating a microwave having a large power to the outside and a microwave having a small power to the inside. CONSTITUTION:When a predetermined amount of etching gas is introduced through a gas inlet tube 5 into an outer discharge tube 2, a plasma is generated in the tube 2 by the operation of a magnetic field to satisfy electron cyclotron resonance condition generated by a microwave and a coil 4. This plasma tends to be diffused along the line of magnetic force of the magnetic field generated from the coil 4, but since there is an inner discharge tube 3, a central high density plasma cannot be diffused to downstream. Accordingly, a plasma low density part generated in the tube 2 arrives at the vicinity of a wafer through between the tubes 2 and 3. On the other hand, a plasma is generated similarly to the tube 2 in the tube 3, but since the applied microwave power is small, a considerably high density plasma is not generated. Thus, the density of the center does not become high, but an apparatus for uniformly etching can be obtained.