Dual-metal self-aligned wires and vias

A method of forming a semiconductor structure comprising:

• forming mandrels on a semiconductor substrate;
• depositing a first conductive layer on the mandrels so as to cover the mandrels;
• depositing a second conductive layer over the first conductive layer;
• removing a portion of the second conductive layer and a portion of the first conductive layer to form first conductive spacers comprising the first conductive layer and second conductive spacers comprising the second conductive layer, at least one of the second conductive spacers adjacent to and in contact with each of the first conductive spacers to form combined conductive spacers;
• forming an interlayer dielectric (ILD) to cover the first and second spacers except for exposed edges of the first conductive spacers;
• patterning the exposed edges of the combined conductive spacers to recess the edges of the combined conductive spacers in predetermined locations to form recesses with respect to the ILD and unrecessed edges with respect to the ILD;
• and
• filling the recesses with an insulating material to leave the un-recessed edges of the first conductive spacers as vias to subsequent wiring features.