Characteristics of Silicon Carbide Etching Using Magnetized Inductively Coupled Plasma

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In this study, SiC etching was carried out using fluorine-based magnetized inductively coupled plasmas. The SiC etch rates and etch selectivities of SiC to Cu and Ni were investigated for the purpose of obtaining high etch rates in the application of SiC etching to various optical devices and micro-electromechanical systems (MEMS). Among SF6, CF4 and NF3, SF6 showed the highest SiC etch rates and etch selectivities to Cu and Ni, due to its highest F atomic density and to the formation of nonvolatile fluoride on Cu and Ni. Cu generally showed higher etch selectivity than Ni, possibly due to the easier formation of fluoride in this case. The application of a weak axial magnetic field ranging from 0 to 80 G showed maximum SiC etch rates at 40 G, possibly due to the formation of a resonance mode. When a field of 40 G was applied, the SiC etch rate was increased approximately two times and, in this condition, the F atomic density and ion densities in the plasma were also at a maximum. The highest SiC etch rate obtained in our experiment was 2020 nm/min with an inductive power of 1400 W, a bias voltage of $-600$ V, a pressure of 10 mTorr of SF6, and a magnetic field of 40 G. The etch selectivity to Ni obtained in this condition was about 40.
2005-03-15