| 摘要 |
PURPOSE:To improve the integration density and to prevent a step part between the surface of a semiconductor substrate and a field isolating region, by forming the field isolating region in specified regions on the planar part of the semiconductor substrate, the side surface part of a groove and the bottom part of the groove by a selective oxidation method in a self-aligning manner. CONSTITUTION:A silicon oxide film 5, a silicon nitride film 4, a silicon oxide film 3 and a silicon substrate 1 sequnetially undergo anisotropic plasma etching, and a groove structure 6 having a specified depth is formed. Then, a silicon oxide film 3A similar to the silicon oxide film 3 is formed along the entire surface of the cross section of the silicon substrate 1 in the groove structure 6. A silicon nitride film 7 is deposited on the entire surface of the silicon nitride film 4 and the entire surface of the inner region of the groove structure 6. Then resist is applied on the entire surface of the silicon nitride 7 to a thickness sufficient to bury the groove structure 6, and a photoresist layer 8 is formed. A pattern for sepcifying a field isolating region is formed. After the photoresist layer 8 is removed, RIE is performed. Then, the silicon nitride film 7 is removed from the entire surface of the silicon substrate 1, but the silicon nitride film 7, which is formed on the side surface of the groove structure 6, remains intact. Then, a part, where the silicon nitride film is not present, is selectivley oxidized, and a field isolating oxide film 10 is formed.
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