Patent ID: 7790602

Claim:
A method of forming a metal interconnect structure on a semiconductor substrate, the method comprising: etching an isolation structure in the metal interconnect structure to form a trench in the metal interconnect structure, the metal interconnect structure having a first pair of horizontally adjacent metal traces that lie above a top surface of the semiconductor substrate, and a second pair of horizontally adjacent metal traces that lie above the first pair of horizontally adjacent metal traces, the trench lying between the first pair of horizontally adjacent metal traces, lying between the second pair of horizontally adjacent metal traces, and extending continuously from a point between the first pair of horizontally adjacent metal traces to a point between the second pair of horizontally adjacent metal traces, the isolation structure lying laterally between and touching the first pair of horizontally adjacent metal traces before the trench is formed, and lying between a metal trace of the first pair of horizontally adjacent metal traces and a metal trace of the second pair of horizontally adjacent metal traces; forming a dielectric structure in the trench, the dielectric structure in the trench touching the isolation structure, lying between the first pair of horizontally adjacent metal traces, lying between the second pair of horizontally adjacent metal traces, and extending continuously from a point between the first pair of horizontally adjacent metal traces to a point between the second pair of horizontally adjacent metal traces, the dielectric structure that only lies directly between the second pair of horizontally adjacent metal traces lying directly vertically above and spaced apart from the dielectric structure that only lies directly between the first pair of horizontally adjacent metal traces; and etching the dielectric structure to remove the dielectric structure that lies directly between the second pair of horizontally adjacent metal traces, and leave the dielectric structure that lies directly between the first pair of horizontally adjacent metal traces.