Plasma etching method and apparatus therefor

摘要

A fluorine-containing compound gas, e.g., SF₆ gas, is converted into a plasma and a silicon portion of an object to be processed is etched by the plasma. At the same time, using a light source having a peak intensity of light in a wavelength range of light absorption of a reaction product, e.g., SiF₄, for which, to be more precise, ranges from 9 mum to 10 mum, the light is irradiated onto a surface of an object to be processed from the light source. The SiF₄ molecules absorb the light, become activated and gain kinetic energy to be used in gaining an easy escape from a hole. As a consequence, an amount (a partial pressure) of fluorine radicals (F*) used as an etchant is increased and an etching rate of a silicon is increased.