| 摘要 |
PURPOSE:To improve the reliability of wirings by burying a polycrystalline silicon film through a silicon oxide film in a U-shaped groove formed on a semiconductor substrate. CONSTITUTION:An SiO2 film 12 and an Si3N4 film 13 are laminated and covered on an Si substrate 11, covered thereon with a protective insulating film 14, a resist film mask 15 is further selectively formed thereon, and the substrate 11 is reactive ion-etched to form a U-shaped groove 16. Then, the film 13 exposed on the side in the groove 16 is side-etched to eliminate the overhung Si3N4 film, the upper surface of the groove 16 is formed in a shape opened in a tapered state, the film 14 is further removed by etching, and a polycrystalline film is buried through the SiO2 film in the groove without air gap. Thus, the surface of the groove separation zone is flattened without step, and even if a wiring layer is formed on the upper surface, wirings having no disconnection and high reliability is formed to enhance the reliability of an IC.
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