Via-hole etching for SiC

Four different F-2-based plasma chemistries for high-rate etching of SiC under inductively coupled plasma (ICP) conditions were examined. Much higher rates (up to 8000 Angstrom min(-1)) were achieved with NF3 and SF6 compared with BF3 and PF5, in good correlation with their bond energies and their dissociation efficiency in the ICP source. Three different materials (Al, Ni, and indium-tin oxide) were compared as possible masks during deep SIC etching for through-wafer via holes. Al appears to produce the best etch resistance, particularly when O-2 is added to the plasma chemistry. With the correct choice of plasma chemistry and mask material, ICP etching appears to be capable of producing via holes in SiC substrates. (C) 1999 American Vacuum Society .