LOCAL CRYSTALLOGRAPHIC TEXTURE AND VOIDING IN PASSIVATED COPPER INTERCONNECTS

A correlation between local crystallographic texture and stress-induce d void formation in tantalum-encapsulated, copper interconnects was re vealed by electron backscattering diffraction studies in a scanning el ectron microscope. Lines exhibiting an overall stronger [111] texture showed better resistance to void formation. Furthermore, grains adjace nt to voids exhibited weaker [111] texture than grains in unvoided reg ions of the same line. The locally weaker [111] texture at voided loca tions suggests the presence of higher diffusivity, twist boundaries, T his work, which represents the first characterization of local texture in stress voided, copper lines, helps to elucidate the relative impor tance of the thermodynamic and kinetic factors which govern void forma tion and growth. (C) 1996 American Institute of Physics.