Electrical resistance and mechanical stress in NiCr/Cu/NiCr thin films

NiCr/Cu/NiCr film configurations are used for metallization of chip resisto rs. The influence of a heat treatment on the electrical resistance of these films has been investigated ex situ and in situ. This has been correlated with concentration depth profiles determined by Auger electron spectrometry . Up to 450 degrees C only weak interdiffusion has been found, so that dist inct resistance changes occur only for films with small Cu-sublayer thickne sses. The distinction of NiCr/CuNi/NiCr resistor films with characteristic interdiffusion effects is explained on the basis of phase diagram. In compa rison to copper films, the temperature dependence of the effective biaxial stress in the NiCr/Cu/NiCr film configuration shows a reduced stress relaxa tion due to the plastically undeformable NiCr films. (C) 1999 American Inst itute of Physics. [S0021-8979(99)03102-3].