US Patent 7300825 Customizing back end of the line interconnects

Custom connections between pairs of copper wires in a last damascene wiring level are effected by creating openings in an overlying insulating layer which span a distance between portions of the two wires, then filling the openings with aluminum. The openings can be created (or completed) by a second, maskless UV laser exposure of positive photoresist which is used for patterning the insulating layer. If an opening is not created, an aluminum connecting shape overlying the insulating layer will not effect a connection between the two wires. Similar results can be achieved by laser exposure of a resist used to pattern the aluminum layer, thereby causing breaks in connecting shape when it is desired not to have a connection.