Helium Ion Secondary Electron Mode Microscopy For Interconnect Material Imaging

Abstract

The recently developed helium ion microscope (HIM) is now capable of 0.35 nm secondary electron (SE) mode image resolution. When low- k dielectrics or copper interconnects in ultra large scale integrated circuits (ULSI) interconnect structures were imaged in this mode, it was found that unique pattern dimension and fidelity information at sub-nanometer resolution was available for the first time. This paper will discuss the helium ion microscope architecture and the SE imaging techniques that make the HIM observation method of particular value to the low- k dielectric and dual damascene copper interconnect technologies.