| 摘要 |
PURPOSE:To prevent the side etching of a material layer remaining on a substrate and to form the material layer having a desired pattern size accurately, by removing one of the material layers, which are formed with different materials formed on the substrate by selective ion etching. CONSTITUTION:Thermal oxidation of a semiconductor substrate 21 is performed, and a silicon dioxide film 22 is grown on the substrate 21. A hole 23 is formed in the silicon dioxide film 22 by a ligthography method. A thin pad oxide film 24 is grown on the surface by thermal oxidation again. A siliconnitride film 25 is deposied on the silicon dioxide film 22 and the pad oxide film 24. Then impurities are introduced in the silicon nitride film 25 by ion implantation. Thereafter the silicon nitride is present along the vertical surface of a step part. Then, the side surface of the residue 26 is covered by the silicon dioxide 22. The residue 26 of the silicon nitride is removed by selective etching. Thereafter, the selective etching of the silicon dioxide is performed, and the pad oxide film 24 immediately beneath the residue 26 is removed.
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