FORMING METHOD FOR MULTILAYER WIRING OF SEMICONDUCTOR DEVICE

PURPOSE:To prevent the defective connection of the connecting section of upper and lower layer wirings by adding a metal M, which reduces Al2O3 while forming MO and M2O3 by itself, into Al of the upper layer wiring. CONSTITUTION:Al2O3 is chemically stable, but can be reduced. An Al alloy containing 0.1-0.3% of the metal Th, La, Be, Mg, Ca, Ba or the like of strong oxidizability capable of reducing Al2O3 is used as an upper layer wiring material. The dissociation energy of the oxides of these metals is larger than Al2O3, they are chemically stable, and they can reduce Al2O3 into Al. A sintering temperature of 400-500 deg.C used for forming the connection of the upper and lower wirings is sufficient for reduction. MO and M2O3 formed take several massive shapes, and the lower layer Al wiring with Al2O3 naturally formed on the surface and the upper layer Al alloy wiring are Al-Al connected. An effect is not displayed when the quantity of the metal being added is less than 0.01%, and MO and M2O3 obstruct connection when it is 0.3% or more.