SILICON ANISOTROPICALLY ETCHING METHOD AND APPARATUS THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a silicon anisotropically etching method and an apparatus thereof which makes a high-anisotropy and a good etched shape compatible with a high etching rate and high selectivity. SOLUTION: In etching a silicon film on an insulation film in a plurality of patterns different in size, the film is etched in an initial stage using a plasma pulled in by applying an ac power of a high frequency (13.56 MHz), and then etched using a plasma pulled in by intermittently applying an ac power of a low frequency (380 KHz). The former etching is switched to the latter etching at a timing when the etching in the highest etching rate pattern (the largest size pattern) proceeds to an interface with a lower insulation film. This timing is detected by an end point detector 10.