Copper interconnects are used in integrated circuits to reduce propagation delays and power consumption. Since copper is a better conductor than aluminium, ICs using copper for their interconnects can have interconnects with narrower dimensions, and use less energy to pass electricity through them. Together, these effects lead to ICs with better performance. They were first introduced by IBM, with assistance from Motorola, in 1997.
The transition from aluminium to copper required significant developments in fabrication techniques, including radically different methods for patterning the metal as well as the introduction of barrier metal layers to isolate the silicon from potentially damaging copper atoms.
