Methods to reduce metal bridges and line shorts in integrated circuits

Abstract

In the first option of the present invention, a semiconductor structure is provided and an overlying titanium nitride barrier layer is deposited thereon at about 100° C. At least Al and Cu is sputtered over the titanium nitride barrier layer from about 270 to 300° C. to form an Al—Cu alloy containing metal layer. The sputtered Al—Cu alloy containing metal layer is promptly cooled at a cooling rate greater than about 100° C./minute to a temperature below 200° C. to form a Al—Cu alloy containing metal layer having minimal CuAl grain growth. The semiconductor structure is removed from the cooling chamber and the semiconductor structure is processed further below 200° C. to form semiconductor device precursors. In the second option of the present invention, a semiconductor structure having an overlying barrier layer is provided. At least Al and Cu is sputtered over the barrier layer at a first temperature to form an Al—Cu alloy containing metal layer having CuAl grains of a first average size. The semiconductor structure is processed and then heated to a second temperature to dissolve the CuAl grains of a first average size then rapidly cooling to a third temperature whereby the CuAl grains formed have a second average size within the Al—Cu alloy containing metal layer. The second average size CuAl grains being less than the first average size CuAl grains.