Method and apparatus for milling copper interconnects in a charged particle beam system

摘要

A method of enhancing charged particle beam etching particularly suitable for copper interconnects, includes milling at non-contiguous locations to prevent the formation or propagation of an etch-resistant region within the rastered area. Two or more milling boxes are typically performed, one or more of the boxes having pixel spacing greater than the spot size, with the last box using a conventional pixel spacing (default mill) smaller than the spot size to produce a uniform, planar floor of the etched area.