| 摘要 |
PURPOSE:To increase the positioning accuracy of multilayer wirings by a method wherein, when a stepped type superposed reference mark to be used for performance of a multilayer wiring process is to be formed, a mark is formed under an interlayer insulating film by performing a bias sputtering, and when the width of the mark is set at W, and the size of the stepping is set at D and the thickness of the insulating film is set at T, the relations of W>2(2T-D) is satisfied, thereby enabling to generate a superposed reference pattern on the insulating film. CONSTITUTION:A protrusion 2 which will be turned to a stepped type mark is formed on an Si substrate 1 by performing a bias sputtering, and an interlayer insulating film 3 is coated on the whole surface including said protrusion 2. At this time, if the width W of the protrusion is not specified, the surface of the film 3 is formed flat, or even when a protrusion 5 corresponding to the protrusion 2 is generated, it is small in shape, and it is unsuitable to be used as a positioning reference. Accordingly, when the width of the protrusion 2 to be used as the reference mark is set at W, its thickness is set at D, the thickness of the film 3 is set to T, W>2(2T-D) is satisfied, thereby enabling to generate an effective protrusion 4 on the film 3. |
