Effect of thermal cycling on stresses in thin silicon nitride and silicon carbide films

摘要

Stresses in thin films are of interest to the microelectronic and coating industries due to their effects on component failures. The stresses in thin films are, in general, comprised of two components: intrinsic stress and thermally induced stress [1,2]. The intrinsic stress is developed in the film during deposition due to the incorporation of defects that do not anneal out at the deposition temperature. In addition, structural changes may also contribute to the intrinsic stress. Thermally induced stresses are developed in the film during heating and cooling due to differences in the thermal expansion coefficient of the film and the substrate. These stresses can lead to failure through delamination, cracking, and void and hillock formation in microchip interconnections [3,4]. For a multilayer thin film structure, as in a microelectronic device, the stress distribution in an individual thin film layer is likely to be influenced by the nature and variation of stresses with temperature in adjoining layers. Therefore, an in-depth understanding of the intrinsic and thermally induced stresses in individual thin film layers may be helpful in defining fabrication processes that would reduce stress induced failures.