| 摘要 |
PURPOSE:To eliminate the adverse effect of a parasitic capacity and so on by removal of the bird's beaks and to contrive the high integration of a semiconductor device by a method wherein the polycrystalline silicon layer formed on the stepped part is selectively removed in consideration of the relation between an impurity concentration and an etching rate. CONSTITUTION:A substrate of a semiconductor device is formed of a semiconductor substrate 1 and an epitaxially grown layer 2, an oxidation-resistant film 4 and an oxide film 5 are formed on an element forming region of the substrate through a pad oxide film 3 and a stepped part is formed so that the element forming region becomes high. Moreover, element isolation regions 9 are formed by performing a selective oxidation and a polycrystalline silicon layer 10, which covers the stepped part and acts as an etching-resistant film except stepped part sidewall parts 11, is formed. The oxide film 5 is etched using this layer 10 as a mask until the substrate is exposed. Furthermore, an anisotropic etching is performed using the stepped part and the regions 9 as masks and grooves 12 are formed. The layer 10 is selectively removed in consideration of the relation between an impurity concentration and an etching rate, bird's beaks 9b are removed and the adverse effect of a parasitic capacity is eliminated.
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