| 摘要 |
PURPOSE:To smooth the step parts of the interlayer insulating film of a semiconductor device, and to prevent the film from alteration by a method wherein a silicate glass layer containing phosphorus in low concentration is formed on the surface of an element having the step parts, phosphorus is diffused in high concentration in the surface, and after it is flowed according to heat treatment, the surface is etched uniformly. CONSTITUTION:A phospho-silicate glass film 4 of low concentration is grown on a polycrystalline silicon layer 1 according to the CVD method. Then thermal phosphorus diffusion is performed on the film 4 to convert the surface into a silicate glass layer 5 containing phosphorus in high concentration. When heat treatment is performed in an oxidizing atmosphere in succession, the high concentration layer 5 flows as to bury the step parts, and favorable form is presented. Moreover, a thermal oxide film 6 is formed on the circumference of the polycrystalline silicon layer 1. After then, when the whole of the surface is etched according to plasma etching, the high concentration layer 5 is removed completely, the smooth step parts according to phospho silicate glass of low concentration is realized, and an aliminum wiring is formed also in favorable shape. Accordingly, the steep step parts can be covered smoothly using the phosphosilicate glass layer of low concentration having superior humidity resistance. |
