Patent ID: 8993449
Filing Date: 2015-03-31
Classification: H01L

Abstract:
1. An etching method for trenches or via holes having high aspect ratio by an NLD type etching apparatus in which a plasma is generated in a processing chamber by radio frequency antenna coils to etch a to-be-processed object made of silicon on a substrate electrode disposed in the processing chamber, the etching method comprising: a hydrogen halide-containing gas-based etching step of etching the to-be-processed object by introducing a hydrogen halide-containing gas into the processing chamber, power being supplied to the substrate electrode and to the radio frequency antenna coils during the hydrogen halide-containing gas-based etching step; a fluorine-containing gas-based etching step of etching the to-be-processed object by introducing a fluorine-containing gas into the processing chamber, power being not supplied to the substrate electrode during the fluorine-containing gas-based etching step; a protective film formation step of forming a protective film on the to-be-processed object by sputtering a solid material disposed to face the to-be-processed object; and a protective film removal step of removing part of the protective film by applying radio frequency bias power to the substrate electrode, wherein the hydrogen halide-containing gas-based etching step is performed first to etch the to-be-processed object made of silicon so as to prevent damage under a mask by etching trenches or via holes having high aspect ratio by the fluorine-containing gas, and thereafter the fluorine-containing gas-based etching step, the protective film formation step, and the protective film removal step are repeated in this order, and wherein the hydrogen halide is at least one selected from the group consisting of hydrogen iodide, hydrogen chloride, and hydrogen bromide.