A novel helium ion microscope for interconnect material imaging

Abstract

The recently developed helium ion microscope (HIM) can be operated in three imaging modes; ion induced secondary electron (SE) mode, Rutherford Backscatter imaging (RBI) mode, and scanning transmission ion imaging (STIM) mode. When low k dielectric or copper interconnects are imaged in these modes, it was found that unique pattern dimension and fidelity information at sub-nanometer resolution is available for the first time. This paper will discuss the helium ion microscope architecture and the imaging modes that may make it a tool of particular value to the low-k dielectric and dual damascene copper interconnect technology.