Abstract: Embodiments of a microelectronic assembly that includes: a package substrate, comprising buildup layers of an organic dielectric material and a plurality of layers of conductive traces in the organic dielectric material, the package substrate having a first surface and a second surface opposite the first surface; and a plurality of integrated circuit (IC) dies coupled to the package substrate on the first side. The plurality of layers of conductive traces comprises a pair of stripline traces or microstrips in one of the layers, the stripline traces or microstrips are surrounded by air gap structures in the organic dielectric material, and the air gap structures are exposed on the first surface.

Abstract: Disclosed herein are silver-coated conductive structures in integrated circuit (IC) package supports, as well as related methods and devices. For example, in some embodiments, an IC package support may include a conductive line, a first material layer on a top surface and on side surfaces of the conductive line, the first material layer including silver, and a second material layer on the first material layer, the second material layer including silicon or aluminum, and one or more of nitrogen and oxygen.

Abstract: Structures are described that include multi-layered adhesion promotion films over a conductive structure in a microelectronic package. The multi-layered aspect provides adhesion to surrounding dielectric material without a roughened surface of the conductive structure. Furthermore, the multi-layered aspect allows for materials with different dielectric constants to be used, the average of which can provide a closer match to the dielectric constant of the surrounding dielectric material. According to an embodiment, a first dielectric layer that includes at least one nitride material can provide good adhesion with the underlying conductive structure, while one or more subsequent dielectric layers that include at least one oxide material can provide different dielectric constant values (e.g., typically lower) compared to the first dielectric layer to bring the overall dielectric constant closer to that of a surrounding dielectric material.

Abstract: Density-graded adhesion layers on conductive structures within a microelectronic package substrate are described. An example is a density-graded adhesion layer that includes a dense region proximate to a conductive structure that is surrounded by a less dense (or porous) region adjacent to an overlying dielectric layer. Providing such a graded adhesion layer can have a number of benefits, which can include providing both mechanical connections for improved adhesion with a surrounding dielectric layer and provide hermetic protection for the underlying conductive structure from corrosive species. The adhesion layer enables the conductive structure to maintain its as-formed smooth surface which in turn reduces insertion loss of signals transmitted through the conductive structure.

Abstract: Structures are described that include multi-layered adhesion promotion films over a conductive structure in a microelectronic package. The multi-layered aspect provides adhesion to surrounding dielectric material without a roughened surface of the conductive structure. Furthermore, the multi-layered aspect allows for materials with different dielectric constants to be used, the average of which can provide a closer match to the dielectric constant of the surrounding dielectric material. According to an embodiment, a first dielectric layer that includes at least one nitride material can provide good adhesion with the underlying conductive structure, while one or more subsequent dielectric layers that include at least one oxide material can provide different dielectric constant values (e.g., typically lower) compared to the first dielectric layer to bring the overall dielectric constant closer to that of a surrounding dielectric material.

Abstract: Density-graded adhesion layers on conductive structures within a microelectronic package substrate are described. An example is a density-graded adhesion layer that includes a dense region proximate to a conductive structure that is surrounded by a less dense (or porous) region adjacent to an overlying dielectric layer. Providing such a graded adhesion layer can have a number of benefits, which can include providing both mechanical connections for improved adhesion with a surrounding dielectric layer and provide hermetic protection for the underlying conductive structure from corrosive species. The adhesion layer enables the conductive structure to maintain its as-formed smooth surface which in turn reduces insertion loss of signals transmitted through the conductive structure.