Patent ID: 8211322

Claim:
A method of patterning a metal layer, comprising: forming a first mask on a surface of the metal layer, the first mask having an opening through the first mask that exposes the metal layer; and forming a nanogap in the exposed metal layer using an ion beam directed through the opening, wherein: the first mask limits a lateral extent of the ion beam, the nanogap has a width that is less than a width of the opening, a first lateral extent of the nanogap is defined by using a top surface of the first mask adjacent to the opening to limit a first lateral portion of the ion beam, a second lateral extent of the nanogap is defined by using a bottom sidewall of the opening to limit a second lateral portion of the ion beam, a sidewall of the opening is angled such that the top surface of the first mask, adjacent to the opening, overhangs the opening and the ion beam is vertically incident on the top surface of the first mask.