Patent ID: 6863787

Claim:
A method of removing one or more mixed copper and dielectric layers from an area of a target, the method comprising: defining the target area to be removed; directing a focused ion beam toward a first mixed copper and dielectric layer in a first pattern, characterized by a first pixel spacing greater than a spot size characterizing the focused ion beam; directing the focused ion beam toward a first mixed copper and dielectric layer in one or more additional patterns, each of the one or more additional patterns characterized by a pixel spacing and, if more than one additional patterns are used, each of the more than one additional pattern having a progressively closer pixel spacing, until the pixel spacing of the last pattern is less than or approximately equal to the ion beam spot size; thereby substantially removing the first mixed copper and dielectric layer from the target area; directing an oxygen containing gas toward the target area; and directing a focused ion beam toward the target area, thereby removing any remaining first mixed copper and dielectric layer and producing a uniformly smooth floor in the milled target area.