| 摘要 |
PURPOSE:To form an element isolating region even under the condition where a groove is narrow and deep by forming a side etching at the time of etching a substrate, leaving poly-Si at the side surface of groove utilizing an overhanging and filling such groove by oxidation. CONSTITUTION:A first SiO2 film 2 is formed on a wafer and an Si3N4 film 3 is deposited. Thereafter, a photo resist pattern 4 for isolation is formed. The first SiO2 film 2 and the Si3N4 film 3 are etched. Thereafter, a groove 5 is formed by etching the wafer 1 in such a way that the side etching of the specified amount is generated. A second SiO2 film 21 is formed on the bottom surface and side surface of the groove 5, and a poly-Si film 22 is deposited. When the poly-Si film 22 is etched, the first SiO2 film 2 and Si3N4 film 3 under the overhanging part are not etched. Thereby the poly-Si film 22 can be left only under the overhanging part. Thereafter, the poly-Si film 22 is oxidized and the isolating region 23 can be formed. |
