| 摘要 |
PURPOSE:To decrease a capacity without changing a wiring resistance of bit lines or the like, by forming wirings on conductors through two layer structure insulating films such as an upper layer insulating film and a lower layer insulating film and forming cross-sectional areas of these wirings into T shapes to the conductors. CONSTITUTION:An insulating film 2, an electrode layer 3, and a layer insulating film 4 are piled in order on a semiconductor substrate 1, and further bit lines 6 made of aluminium are formed thereon, and next the whole of its periphery is covered with an upper layer insulating film 5. Since the cross-sectional areas of the bit lines 6 are formed into T shapes, capacities on the upper layer part and on the lower layer part are generated independently. When a distance between the bit lines is sufficiently large, a width of the T-shaped upper layer part is more enlarged so that the capacity can be decreased effectively by combining a dielectric constant of the upper layer insulating film 5. Word lines in stead of the bit lines, and further general wirings are applicable for the signal lines. Polycrystal silicon, and high melting point metal, or high melting point metal silicide are usable, or two-layer structure of polycrystal silicon and high melting point metal or high melting point metal silicide is also usable. |
