COMPACT ELECTRON-CYCLOTRON RESONANCE PLASMA-ETCHING REACTOR EMPLOYING PERMANENT-MAGNET

A compact electron cyclotron resonance (ECR) plasma-etching reactor employing Sm-Co magnets was studied. A flattened rectangular waveguide with a slot antenna enabled this ECR system, and the plasma was generated with high density of 2 x 10(12) cm-3 at 1 x 10(-3) Torr of Ar. The silicon etch rate in NF3 was limited at low-gas flow rate because of the redeposition of the etching products dissociated by high-density plasma; but, by increasing flow rate, 5000 angstrom/min was achieved at 1 x 10(-3) Torr under the floating potential of 15 eV. The RF bias of 100 W (430 V of the self-bias) offered a very high etch rate of 2.3-mu-m/min. The directional feature was achieved at 25 W RF bias (180 V of the self-bias) at 5 x 10(-4) Torr. Further, the multi-slot antenna which was excited by independent microwave sources turned out to improve the etching uniformity considerably.