| abstract |
A large volume magnetoplasma is created by (a) establishing a plasma in an electrically isolated, tubular cavity formed by a cylinder (10) containing a source of ions and electrons at low pressure, into which rf energy is coupled by an antenna (32) alongside the cavity; and (b) allowing the plasma to extend into an adjoining auxiliary region (20) which is connected to the cavity (10). Preferably the operating conditions in the cavity (10) are such that the production of atomic species in the plasma is enhanced. The enhancement occurs when the operating conditions satisfy the relationships ##EQU1## where W is the power in watts applied to the antenna (32), D is the diameter of the plasma cavity (10) in cm, p is the pressure in the cavity (10) (and in the auxiliary region (20)) expressed in millitorr, f is the frequency of the rf power in MHz, L is the length of the antenna (32) in cm and B is the magnetic field in the cavity (10), established by a coil (13) which surrounds the cavity, expressed in gauss. The large plasmas so produced are suitable for dry etching of semiconductor materials such as silicon wafers, for etching of polymers and for the surface treatments of other materials. |