| 摘要 |
PURPOSE:To enable to reduce the stress to be applied to the boundary part of the surface of the silicon semiconductor substrate and the isolated groove in the process of thermal oxidation to be performed atfer the isolated groove is formed and to suppress the malfunction of the element, which is caused by the generation of deterioration of the characteristics of the element and a defect of the element due to strain, by a method wherein a curvature is made to hold at the boundary part by the thermal oxide film forming process and the thermal oxide film etching process. CONSTITUTION:A silicon nitride film 12 is coated on a silicon semiconductor substrate 11 in a thickness of 1,000-5,000Angstrom , a pattern is formed by a photo etching method and part of the silicon semiconductor substrate 11 is made to expose. After that, an oxidation is selectively performed on the silicon semiconductor substrate 11 by a thermal oxidation method, a silicon dioxide film 13 of the thickness of 1,000-2,000Angstrom is formed and this silicon dioxide film 13 is removed by an isotropic etching method. Then, an etching is selectively performed on the silicon semiconductor substrate 11 to a depth of 1-6mum by an an isotropic etching method using the silicon nitride films 12 as masks and an isolated groove is formed. After an etching is performed on the silicon nitride films 12, an thickness of 1,000-7,000Angstrom by a thermal oxidation method and a second silicon dioxide film 14 is formed. |
