A NEW HIGH-DENSITY PLASMA-ETCHING SYSTEM USING A DIPOLE-RING MAGNET

A new high-density plasma etching system has been developed using a di pole-ring magnet (DRM). The system utilizes a parallel magnetic field up to 600 G with excellent uniformity extending over 250 mm in diamete r. The nonuniformity of plasma was compared with that of a conventiona l permanent-magnet-enhanced plasma using a gate oxide integrity test. The plasma generated using DRM produced no gate oxide degradation, whi le the conventional magnetron plasma produced some gate oxide degradat ion under the most highly accelerated conditions. Si etch rate is show n to depend strongly on magnetic field strength, increasing from 1.3 m u m/min at 120 G to 2.1 mu m/min at 600 G.