Large dynamic range atomic force microscope

In semiconductor manufacturing, the shrink following Moore’s law requires ever tighter overlay and registration between the different (material) layers. For accurately characterising this overlay and registration, TNO has developed a large dynamic range atomic force microscope demonstrator; the LDR-AFM can measure marker-to-feature distances over several millimeters with sub-nanometer reproducibility. This Mikroniek article describes a highly stable metrology concept and a 6-degrees-of-freedom positioning platform (hexapod) carrying an AFM scan head able to move the AFM probe tip. Repeatability measurements have demonstrated that both drift and reproducibility figures are well below the smallest feature size of the newest semiconductor processing nodes.