RELATIONSHIP OF CRYSTALLOGRAPHIC ORIENTATION AND IMPURITIES TO STRESS, RESISTIVITY, AND MORPHOLOGY FOR SPUTTERED COPPER-FILMS

Copper has 44% higher conductivity than aluminum, making copper an att ractive interconnect metal for advanced multilevel interconnections in integrated circuits (IC) and multichip modules (MCM). Since sputter d eposition is widely used in IC and MCM fabrication, the properties of sputtered copper films are investigated in this study. In particular, MCM technology requires relatively thick coatings (5-8 mum), which can result in high stress. Thin film stress can lead to dielectric cracki ng, wafer bow, and reduced operating lifetime. This study reports the residual stress, morphology, and electrical resistivity of annealed co pper coatings as a function of the thin film crystal orientation deter mined by x-ray diffraction. We found that the stress and electrical re sistivity of copper thin films can be significantly reduced by control ling the orientation of the copper crystallites.