Texture inheritance in Al(Cu) interconnect materials

Deposition surface morphology plays a major role in governing the texture w ithin sputter deposited Al (0.5% wt., Cu) films. The presence of a thin Ti barrier layer provides an epitaxial template for Al(Cu) atoms to grow. Howe ver, the topography of the surface on which the Ti is deposited also influe nces Al(Cu) film texture. Through a combination of x-ray pole figure analys is and scanning electron microscopy, we observed that the behavior of (111) texture of Al(Cu) films deposited on Ti is dictated by the underlying surf ace roughness. A quantitative link between the offset in maximum Al (111) t exture from the substrate normal and the average surface orientation of the deposition surface has been established. Information from atomic force mic roscope scans of the underlying surface has been used to construct a surfac e offset distribution (SOD), which contains the distribution of local orien tations within a surface. Above a threshold roughness of the deposition sur face, the SOD maxima correspond to the observed offset Al (111) texture in Al(Cu)/Ti films deposited on a variety of interlevel dielectric layers. (C) 2001 American Institute of Physics.