| 摘要 |
PURPOSE:To make the shape of a contact hole smooth using difference of etching speed by forming any one layer of a phosphoric silica glass film which has inclined concentration of phosphorus varying to the direction of depth, polysilicon, a diffusion layer or an aluminum wiring. CONSTITUTION:On a silicone semiconductor substrate 1, phosphoric silica glass 2 is formed by chemical vapor growth. In this case, the phosphoric concentration distribution in the phosphoric silica glass 2 is made higher toward the surface. If the phosphoric silica glass film 2 is etched by reactive ion etching using a mask of photo resist 3, the angle 4 of a contact hole is made sharper. Then, if etched using fluoric acid solution which has a selectivity of higher etching speed in higher concentration of phosphorus in phosphoric glass, the shape of the angle 4 can be made smooth without considerably widening the bottom of the contact hole which has lower concentration of phosphorus. |
