Etching

Patent Pending The present invention includes a load chamber into which a substrate is introduced and an RIE apparatus for performing reactive ion etching treatment on the substrate. The inner surface of the process chamber of the RIE apparatus is coated with an anodized Al2O3 film in a nonaqueous solution. As pre-processing, ultraviolet rays with a wavelength of 120 nm to 190 nm is applied to the substrate by an irradiation apparatus in a gas atmosphere containing no oxygen atom and no water molecule, and the substrate is subjected to heating processing at a temperature of 170 DEG C or higher. According to the present invention, the selectivity in the etching treatment is increased.