<p>Disclosed is a plasma etching method which can prevent the formation of a bowing shape and enables the formation of a tapered etching structure (a hole or groove) having a smooth surface. A tapered etching structure (H) (a hole or groove) having a wide upper opening width and a narrow bottom width can be formed on a silicon substrate (K) by carrying out a first step of using a fluorine-containing gas and a nitrogen gas, converting these gases into a fluorine-containing plasma gas and a nitrogen plasma gas simultaneously and etching the silicon substrate (K) with the fluorine-containing plasma gas while forming an etching-resistant layer on the silicon substrate (K) with the nitrogen plasma gas, and carrying out a second step of using a fluorine-containing gas and an oxygen-containing gas, converting these gases into a fluorine-containing plasma gas and an oxygen-containing plasma gas simultaneously and etching the silicon substrate (K) with the fluorine-containing plasma gas while forming an etching-resistant layer on the silicon substrate (K) with the oxygen-containing plasma gas.</p>
