Various components used in microelectronic packaging or in interconnecting microelectronic packages can includes conductive features formed in a support structure in the form of a substrate or the like having vias or other routing or distribution circuitry formed therein. Such features are typically formed from various wiring metal such as copper, gold, nickel, aluminum, etc., which are formed in a support structure such as, for example, a thin dielectric or semiconductor material layer, by a number of different methods.
In some instances, the materials used to form such conductive features were made from a material of the type listed above in a form having impurities therein. Such materials, such as oxygen, nitrogen, chlorine, and carbon, occurred naturally within the material or were added to the material as a by-product of various mineral extraction or processing steps. These and other impurities within the wiring material were known to increase the resistivity of the wiring material, which can slow the performance of microelectronic packages or package assemblies including such wiring material and increase operating temperatures thereof. In addition, these impurities sometimes directly resulted in failure or the creation of defects within wiring circuitry by causing small explosions within the wiring material within which they were embedded. In an effort to reduce the resistivity of components and to otherwise increase their reliability, the previously discussed impurities were reduced in the wiring materials by additional processing, for example, to result in wiring material that was substantially more pure than that which was previously used. The removal of such impurities, however, lead to increased grain size within the wiring material used, which accordingly resulted in a decreased mechanical strength for such materials.
The reduced strength in the materials used to form wiring circuitry can lead to failure within the components within which they are formed. Such failure can include fracture within components due to heat cycling of support structures or other related components. Additional failure can be in the form of delamination from within support structures due to plastic deformation of the wiring components caused by elastic deformation of support structures or thermal expansion thereof. Accordingly, a wiring metal composition and associated method are needed that produce high strength wiring components while maintaining an acceptable level of resistivity without susceptibility to failure modes similar to those of low-purity wiring metals.