FOCUSED ION BEAM METROLOGY

A focused ion beam metrology device and method are disclosed. A focused ion beam is used to measure dimensions of semiconductor features, such as top-down linewidth measurement. Low intensity focused ion beams form top view images of the semiconductor. High intensity focused ion beams etch the semiconductor in the presence of etch-enhancing material. A crater is etched to expose a cross-section the of semiconductor. The cross-section is imaged by directing low intensity focused ion beams toward the cross-section. This may be achieved by tilting the semiconductor. A three dimensional profile of a feature may be formed by successively etching the feature top surface and forming a top view image thereof. Overlaying the successive top view images forms the three dimensional profile.