| 摘要 |
The disclosure relates to a plasma etch chemistry which allows a near perfectly anisotropic etch of silicon. A Cl-based plasma etch such as SiCl<SUB>4</SUB> + Cl<SUB>2</SUB> has CH<SUB>2</SUB>Br<SUB>2</SUB> added thereto, readily allowing the anisotropic etching of silicon. The silicon surface facing the discharge is subjected to ion bombardment, allowing the volatilization (etching) of silicon as a Si-Cl-Br compound. The Br which adsorbs on the sidewalls of the etched silicon passivates them from the etching. This new plasma etch chemistry yields a very smooth etched surface, and the etch rate is relatively insensitive to the electrical conductivity of the silicon. The use of dibromomethane is an improvement over the prior art which typically used HBr; a poisonous and ozone depleting gas. Dibromomethane is a relatively safe gas and not ozone depleting, yet giving substantially similar results in plasma etching of silicon, silicon nitride, and other materials. |
