Surface finish for wirebonding
The present disclosure provides embodiments of package devices and methods for making package devices for a semiconductor die. One embodiment includes a die mounting structure having a finished bond pad that includes a copper bond pad and a cobalt-containing layer over a top surface of the copper bond pad, and a wire bond structure that is bonded to a top surface of the cobalt-containing layer of the finished bond pad, where cobalt-containing material of the cobalt-containing layer is located between a bottom surface of the wire bond structure and the top surface of the copper bond pad such that the cobalt-containing material is present under a center portion of the wire bond structure.
1. A package device for a semiconductor die comprising:
a package substrate having a first finished bond pad that comprises a copper bond pad and a cobalt-containing layer over and directly contacting a top surface of the copper bond pad; and
a first wire bond structure bonded to and directly contacting a top surface of the cobalt-containing layer of the first finished bond pad, wherein
cobalt-containing material of the cobalt-containing layer is located between a bottom surface of the first wire bond structure and the top surface of the copper bond pad such that the cobalt-containing material is present under a center portion of the first wire bond structure.
2. The package device of claim 1 , further comprising:
a finished ball pad on the package substrate, the finished ball pad comprising a copper ball pad and the cobalt-containing layer over a top surface of the copper ball pad; and
a solder ball bonded to a top surface of the cobalt-containing layer of the finished ball pad for a ball grid array (BGA) connection.
3. The package device of claim 1 , wherein the package substrate comprises at least one of a ceramic substrate, an organic substrate, an epoxy substrate, and a polyimide substrate.
4. The package device of claim 1 , wherein the first wire bond structure comprises at least one of a stitch bond, a wedge bond, and a ball bond.
5. The package device of claim 1 , wherein the first wire bond structure is part of a wirebond connection between the first finished bond pad on the package substrate and the semiconductor die, and wherein the wirebond connection further comprises a second wire bond structure that is bonded to a second finished bond pad on the semiconductor die.
6. The package device of claim 1 , wherein the cobalt-containing material comprises at least one element of a group of: cobalt, tungsten, boron, phosphorous, nickel, molybdenum, and rhenium.
7. The package device of claim 1 , wherein the cobalt-containing material minimizes oxidation on the copper bond pad.
8. The package device of claim 1 , further comprising:
a wirebond connection that includes the first wire bond structure, the wirebond connection comprising copper coated with the cobalt-containing material.
9. The package device of claim 1 , further comprising:
encapsulant material that encapsulates the first finished bond pad and the first wire bond structure.
10. The package device of claim 5 , further comprising:
encapsulant material that encapsulates the first finished bond pad, the first wire bond structure, the second wire bond structure, and the second finished bond pad.