| 摘要 |
PURPOSE:To enhance the breakdown withstand voltage of a film, increase a capacity value and facilitate the manufacture, by forming a plurality of insulating films with the same film thickness in different dielectric constants on a substrate. CONSTITUTION:An N type impurity layer 2 is formed on a P type Si substrate 1, and thick Si oxide films 3a, 3a', an N type high density impurity 4, non-doped polycrystalline Si 5, a nitride film 6 and an open hole part B are formed by selective oxidation method. A thin oxide film 3c for capacity is formed. Thereat, the formation is performed by a dry oxygen atmosphere system. The nitride film 6 is formed over the entire surface. The nitride film 6 is selectively etching- removed resulting in the formation of an open hole part C. An oxide film 3d for capacity is formed on the open hole part C. This oxidation is performed in a steam atmosphere. The quality of oxide films varies with an oxidation system, and oxide films with different capacity values though with the same thickness can be formed. Besides, the stepwise difference in a capacity part can be reduced, and the problem on a wiring structure can be solved. |
