| 摘要 |
PURPOSE:To prevent direct contact of a BPSG film with a substrate and an interconnection layer including a contact part, by covering the lower layer of the BPSG film as a smooth coating film with an underlay film, and covering the upper layer by an insulating film other than said BPSG film. CONSTITUTION:On a silicon semiconductor substrate 1, a first underlay oxide film 2, a PSG film 3 as a second underlay insulating film and a BPSG film 4 as a smooth coating film are sequentially formed. An opening 7a, which has a slightly larger size, is provided by an anisotropic etching in the parts of the surface of the BPSG film 4 and the PSG film 3. Then, by the reflow treatment of the BPSG film 4, the surface side facing the opening 7a is made to be the gentle curved surface. After an SOG film 5 is applied and formed thereon, an opening is provided at specified dimensions in the SOG film 5, the BPSG film 4, the PSG film 3 and the underlay oxide film 2 by anisotropic etching. Thus a contact hole 7 is formed. In this way, the BPSG film 4 as the smooth coating film is completely covered with the lower PSG film 3 and the upper SOG film 5.
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