Etching method

Abstract

In an etching method of the present invention, a first etching step for etching a silicon semiconductor region at a first etching rate with use of a first etching gas is first performed. Then, after the first etching step, a second etching step is performed in order to etch the silicon semiconductor region at a second etching rate that is lower than the first etching rate by using a second etching gas that includes carbon and fluoride, with the ratio of the fluoride in the second etching gas being higher than that of the carbon therein. Carbon is included in the second etching gas in order to chemically bind to at least either oxygen or hydrogen used in the first etching step. Therefore, it is possible to inhibit the generation of black silicon (i.e., a residue composed of silicon needles) which is caused as a result of attachment of oxygen and hydrogen on the etching surface. The resulting etched surface is smoothly formed, and black silicon is not formed thereon.

Dependencies are inferred from the claim text.