| 摘要 |
PURPOSE:To realize a region, with its surface roughly flat and divided by an oxide film by a method wherein a polycrystalline silicon film is formed on the surface of a substrate provided with a groove, said film is converted into an oxide film by thermal oxidation, and said oxide film is retained only inside the groove. CONSTITUTION:A groove is formed in a silicon substrate 1 by anisotropic etching with a photoresist 2 serving as a mask. The photoresist 2 is removed and then a thermal oxide film 4 is formed. Next, a polycrystalline silicon film 5 is grown by the vapor phase growth method. The thickness of the polycrystalline silicon film 5 should preferably be approximately a half of the depth of the groove so that it may be flush with the surface of the silicon substrate 1 after oxidation. A process follows wherein the polycrystalline silicon film 5 is subjected to thermal oxidation for the formation of a thermal oxide film 6 on the silicon substrate 1. A photoresist 7 is formed with its pattern approximately corresponding to the groove, and the photoresist 7 serves as a mask in a process of etching the oxide film 6. In this last process etching rates are chosen respectively for the surface and inside of the oxide film 6 so that an oxide film 8 may have a roughly flat surface. |
