METHOD TO FORM COPPER INTERCONNECTS BY ADDING AN ALUMINUM LAYER TO THE COPPER DIFFUSION BARRIER

摘要

A method to form copper interconnects is described. Themethod may be used to form single or dual damasceneinterconnects. The addition of an aluminum barrier layerto the conventional barrier layer creates a superiorbarrier to copper diffusion. A substrate layer isprovided. A dielectric layer is deposited overlying thesubstrate layer. The dielectric layer patterned to forminterconnect trenches. An optional titanium adhesion layermay be deposited. An aluminum barrier layer is depositedoverlying the interior surfaces of the trenches. A secondbarrier layer, comprising for instance titanium andtitanium nitride, is deposited overlying the aluminumbarrier layer. A copper layer is deposited overlying thesecond barrier layer and filling the interconnect trenches.The copper layer, the second barrier layer, and thealuminum barrier layer are polished down to the top surfaceof the dielectric layer-to define the copper interconnects,and complete the fabrication of the integrated circuitdevice.