Electromigration resistant and profile consistent contact arrays

A composite device assembly comprising:

• a plurality of dies, each die of the plurality of dies includes a respective array of contacts;
• a substrate extending from a first substrate end to a second substrate end;
• the substrate includes one or more embedded multi-die interconnect bridges (EMIB) having associated conductive traces;
• first and second via assemblies coupled between the respective arrays of contacts and the conductive traces of the one or more EMIB, and each of the first and second via assemblies includes:
• a base pad including at least a first conductive material;
• a cap assembly including at least a second conductive material;
• a via interposed between the cap assembly and the base pad, and one or more of the cap assembly or the via includes an electromigration resistant material configured to isolate each of the base pad and the cap assembly from intermetallic compound growth;
• and
• wherein each cap assembly and via of the first via assembly has a first assembly profile less than a second assembly profile of the cap assembly and via of the second via assembly, and the first and second cap assemblies include application and reflowed configurations:
• in the application configuration the first and second cap assemblies have a common applied thickness;
• and
• in the reflowed configuration the first and second cap assemblies have a thickness variation of ten microns or less.