| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to remove easily a residual gate material and to prevent continuity from being made between gates by a method wherein the end parts of a buried element isolation region are formed into a step shape. SOLUTION: An oxide film 2, a first stopper 3 and a second stopper 4 are formed on a semiconductor substrate 1. The first and second stoppers are selected by a combination of stoppers of different oxidation rates, stoppers of different isotropic etching rates or the like. Then, the stoppers 3 and 4 and the film 2 are patterned to form a resist 7 and the stopper 4 consisting of a silicon nitride layer, the stopper 3 consisting of a polycrystalline silicon layer, the film 2 and the substrate 1 are subjected to anisotropic etching. After the resist 7 is removed, an oxide film 5 is formed by performing an oxidation in a thickness of several 10nm or thereabouts. At this time, as the stopper 3 is a substance which is easily oxidized, the film 5 is mainly grown and formed in the lateral direction. An SiO2 film or the like is deposited on the substrate 1 to bury the SiO2 film in, an insulating film 6 is formed, CMP(chemical- mechanical polishing) is performed to polish the film 6 and these stoppers 3 and 4 are removed from the film 2 by isotropic etching.
|
