Etching method

Abstract

A low-temperature etching method including an etching step of setting the temperature of a member to be etched having an etching object containing silicon to 0° C. or less, bringing an etching gas containing an etching compound into contact with the member to be etched, and etching the etching object. The etching gas contains or does not contain high-boiling-point impurities, the high-boiling-point impurities being compounds having at least one type of atom among a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a hydrogen atom, and an oxygen atom in the molecule and having a boiling point of 20° C. or more under a pressure of 101 kPa, and, when the etching gas contains the high-boiling-point impurities, the total concentration of all types of the contained high-boiling-point impurities is 500 ppm by volume or less.

Dependencies are inferred from the claim text.