| 摘要 |
PURPOSE:To prevent the generation of breaking and thinning off of wires which will be formed on an oxide layer by a method wherein a polycrystalline silicon layer is formed on the lower wiring layer through the intermediary of a silicon nitride film, and the polycrystalline silicon layer is converted into an oxide layer, thereby enabling to flatten the surface of the oxide layer. CONSTITUTION:A thermal oxide film 2 is formed as an insulating film on the whole surface of the silicon semiconductor substrate 1 whereon a prescribed semiconductor element is formed, and a contact window 3 is formed. A highly conductive polycrystalline silicon layer whereon impurities of high density are doped is formed, and a lower wiring layer and a gate electrode 4 to be used for an MOS transistor are formed by performing an etching. A silicon nitride film 5 is formed on the whole surface by performing a CVD method. A polycrystalline silicon layer is formed and it is converted into an oxide substance layer 7 by performing a thermal oxidizing process. The cubic volume of silicon is expanded approximately 4.8 times, all the recessed parts are filled up, and an almost flat surface is obtained. A window 8 is formed, and an upper wiring layer 9 is formed. As the surface of the oxide substance layer 7 is flattened, an excellent step coverage can be obtained. |
