| 摘要 |
PURPOSE:To confirm the end of etching, by a method wherein a silicon oxide film, a silicon nitride film and a film of material having smaller etching rate than that of silicon nitride are formed on element forming region, and a silicon nitride film is formed on whole surface and then directional etching is performed. CONSTITUTION:On element forming region of a substrate 1 are formed a silicon oxide film 2, a silicon nitride film 3 and a monocrystalline silicon film 6 in order, and a silicon nitride film 4 is formed on whole surface of the substrate 1. Etching is performed by reactive ion etching process of trifluoromethane until the polycrystalline silicon film is exposed, thereby silicon surface in isolation region between elements is exposed. The polycrystalline silicon film 6 is removed by etching of potassium hydroxide solution and silicon in the isolation region between elements is solved at depth of about 1mum and an oxide layer is formed, and then the silicon oxide film 2 and the silicon nitride film 3 are removed. |
