| 摘要 |
PURPOSE:To bury an insulating film in a preferable shape in a recess by forming the first insulating film having a thickness of 1/2 or larger of the width of the hole of the recess on the surface of a semiconductor substrate which has sides and bottom of the recess and further the second insulating film thereon. CONSTITUTION:A recess 2 of 3mum or depth is formed toward the interior from the surface of a substrate 1. Then, boron ions are implanted to the bottom of the recess 2 to form a P<+> type region. Then, an oxide film 4 of 0.8mum thick is formed by a chemical vapor phase growth (VCD) method on the surface of a semiconductor substrate which has the recess 2. Then, a boron phosphorus glass (BPSG) of 1.0mum thick is formed by a CVD method on the top of the film 4. Thereafter, a heat treatment is executed in nitrogen atmosphere, and the surface of a BPSG film 5 is flattened. Subsequently, the film 5 of the second insulating film and the film 4 of the first insulating film are etched back. The film 4 is prevented from being rapidly etched in the recess by this structure.
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