Via-hole etching for SiC

Four different F-2-based plasma chemistries for high-rate etching of SiC un der 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 d issociation efficiency in the ICP source. Three different materials (Al, Ni , and indium-tin oxide) were compared as possible masks during deep SIC etc hing for through-wafer via holes. Al appears to produce the best etch resis tance, particularly when O-2 is added to the plasma chemistry. With the cor rect choice of plasma chemistry and mask material, ICP etching appears to b e capable of producing via holes in SiC substrates. (C) 1999 American Vacuu m Society .