Coating of copper and silver air bridge structures to improve electromigration resistance and other applications

A method of forming an air bridge structure between a first and second circuit component on a substrate, the method comprising:

• forming a support structure on the substrate;
• forming vias in support structure above the first and second circuit components;
• depositing a conductive layer so as to form vertically extending legs in the vias and a laterally extending member between the upper portions of the vertically extending legs in a manner so as to form an air bridge structure that electrically interconnects the first and second circuit components, wherein forming the laterally extending member exposes grain boundaries adjacent the surface of the laterally extending member resulting in an increased resistivity through the air bridge structure;
• removing the support structure so as to suspend the laterally extending member above the substrate between the first and second circuit components via the vertically extending legs, wherein removing the support structure results in forming grain boundaries in the laterally extending member and the vertically extending legs, which increases resistivity through the air bridge structure;
• and
• processing the air bridge structure by coalescing the grain boundaries so as to form fewer grain boundaries, which results in a decreased resistivity through the air bridge structure.