NF3/H2 REMOTE PLASMA PROCESS WITH HIGH ETCH SELECTIVITY OF PSG/BPSG OVER THERMAL OXIDE AND LOW DENSITY SURFACE DEFECTS

摘要

A method and apparatus for selectively etching doped semiconductor oxides faster than undoped oxides. The method comprises applying dissociative energy to a mixture of nitrogen trifluoride and hydrogen gas remotely, flowing the activated gas toward a processing chamber to allow time for charged species to be extinguished, and applying the activated gas to the substrate. Reducing the ratio of hydrogen to nitrogen trifluoride increases etch selectivity. A similar process may be used to smooth surface defects in a silicon surface.