Integrated circuits, the key components in thousands of electronic and
computer products, include interconnected networks of electrical
components. The components are typically wired, or interconnected,
together with aluminum wires. In recent years, researchers have begun
using copper instead of aluminum to form integrated-circuit wiring,
because copper offers lower electrical resistance and better reliability
at smaller dimensions. However, copper typically requires use of a
diffusion barrier to prevent it from contaminating other parts of an
integrated circuit. Unfortunately, typical diffusion barrier materials
add appreciable resistance to the copper wiring, and thus negate some
advantages of using copper. Moreover, conventional methods of forming the
copper wiring are costly and time consuming. Accordingly, the inventors
devised one or more exemplary methods for making integrated-circuit
wiring from materials, such as copper-, silver-, and gold-based metals.
One exemplary method removes two or more masks in a single removal
procedure, forms a low-resistance diffusion barrier on two or more wiring
levels in a single formation procedure, and fills insulative material
around and between two or more wiring levels in a single fill procedure.
This and other embodiments hold the promise of simplifying fabrication of
integrated-circuit wiring dramatically.