| 摘要 |
PURPOSE:To prevent defect in coverage of an interconnection by forming a process in which damage is done to only a surface layer part of layer insulating films ahead of an etching process and making an etching grade dissimilar in the thickness direction of the layer insulating films. CONSTITUTION:An element is formed on a surface of a semiconductor substrate 1, and PSG (phosphorus glass) 2 is piled by a CVD method to form an insulating layer to Al interconnection, and a contact hole is formed, and next a first-layer Al interconnection 3 is formed thereon so as to compose a lower interconnection. Plasma nitriding films 4a and 4b are piled by a plasma CVD method so that layer insulating films are composed in two-layer structure. Next, ion radiation 7 of As<+> is performed to do damage to a second-layer plasma nitriding film 4b. Next, a throughhole pattern is formed by a photoresist 5. The plasma nitriding film is etched by an isotropic dry etching method. The photoresist 5 is removed to form a second-layer Al interconnection 6. The layer insulating films are formed so that a thickness of the second-layer film is less than five times that of a first layer film.
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