| 摘要 |
PROBLEM TO BE SOLVED: To increase the freedom in layout by covering the top of the first wiring layer buried in the groove made in an insulating layer with insulating material of different kind from the insulating layer, as a cap insulator, and arranging a second wiring layer on the cap insulator. SOLUTION: A groove 18 to form buried wiring is made in an insulating layer 2. Next, after exfoliation of resist 17, a polycrystalline silicon film doped with a large quantity of phosphorous impurities is accumulated as the first conductor film all over the surface. Next, the whole face is etched back by anisotropic dry etching, and etch back is performed in such a way that the polycrystalline silicon film remains within the groove 18 so as form buried pit wires 3 and 3a in the groove 18. Next, a silicon oxynitride film is accumulated all over the face as the second insulating film so as to form an insulating film 19 for a cap. Then, the groove 19 wherein the buried bit wires 3 and 3a are buried is filled up completely with an insulating film 19 for a cap. Hereby, the formation of the insulating film to insulate the buried wiring from the silicon substrate 1 becomes needless. |
