Metal cap layer of increased electrode potential for copper-based metal regions in semiconductor devices
AssigneeAdvanced Micro Devices, Inc.
InventorsMarkus Nopper, Axel Preusse, Robert Seidel
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Abstract
A conductive cap material for a copper region may be provided with enhanced etch resistivity by taking into consideration the standard electrode potential of one or more of the species contained therein. For example, instead of a conventionally used CoWP alloy, a modified alloy may be used, by substituting the cobalt species by a metallic species having a less negative standard electrode potential, such as nickel. Consequently, device performance may be enhanced, while at the same time the overall process complexity may be reduced.
Claims20
A semiconductor device, comprising:
- a substrate;
- and
- a metallization system formed above said substrate, said metallization system comprising:
- a metal line formed in a dielectric layer and having a top surface, and
- a conductive cap layer formed on said top surface, said conductive cap layer being comprised of a ternary alloy including tungsten and at least one metal defined by a standard electrode potential that is less negative compared to a standard electrode potential of cobalt.
A method, comprising:
- forming an opening in a dielectric layer formed above a substrate of a semiconductor device;
- filling said opening with a copper-containing metal to form a metal region;
- and
- forming a cap layer comprised of a ternary alloy at least on a top surface of said metal region, said ternary alloy comprising tungsten and at least one metal having a standard electrode potential that is less negative than a standard electrode potential of cobalt.
A method, comprising:
- identifying a wet chemical cleaning recipe designed for removing contaminants after a plasma etch process for patterning a via opening connecting to a copper-containing metal region in a metallization system of a semiconductor device;
- determining an etch rate when applying said wet chemical cleaning recipe to one or more ternary alloys;
- and
- replacing a specified one of the species in said one or more ternary alloys by a substitute species having a less negative standard electrode potential compared to said specified one species when said etch rate is above a predefined threshold.
Dependencies are inferred from the claim text.