Microstructure mapping of interconnects by orientation imaging microscopy

Abstract

Orientation imaging microscopy (OIM) provides a detailed description of the variation in crystallographic structure over the surface of single crystal or polycrystalline bulk materials. This technique has been used in the investigation of interconnect lines and contact pad material in a number of aluminum metallizations on silicon oxide/silicon substrates. The specimens were examined in a scanning electron microscope fitted with apparatus for collecting electron back-scatter diffraction patterns (EBSPs). OIM scans were performed over various regions of each specimen. The technique has provided information regarding the local texture variations between different regions of a thin film structure for both patterned and unpatterned metallizations. It was concluded that significant modification of the microstructure may occur subsequent to the initial metal deposition and that this modification can differ between the unpatterned regions and interconnect lines of varying widths.