Combined x-ray diffraction and wafer curvature measurements during annealing of Ni thin films (13 nm) deposited on Si (001) reveal distinct stages in stress development and silicide growth. Thanks to this unique experimental setup, a clear correlation is established between force extrema at distinct temperatures and the appearance of new silicides. It is shown that the transient formation of Ni3Si2 has a strong influence on the overall stress development.

A new mechanical stress characterization method has been developed for Damascene copper interconnects. The micro strain gauge based on a rotating beam has been fabricated in situ on a standard industrial CMOS production line. Comparison of the beam deviation in the fabricated sensor with usual geometrical model is discussed. The saturation of the beam deviation leads to an analytical model which takes the stiffness of the anchoring points into account. This model gives a direct value of the local stress in the copper line for different annealing times. We show that this value is different from the one given by a curvature measurement method. The microstructure of the Damascene copper induces a higher stress level than full sheet deposition copper. The sensor was developed to be compatible within a CMOS process. It is suitable for in situ mechanical stress monitoring in Damascene lines and process optimization.

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The kinetics of CoSi2 formation via a solid-state reaction between CoSi and single crystal Si has been the object of many studies in the past. Because of the importance of nucleation, complex kinetics has been reported. In this work, we investigate CoSi2 formation kinetics with in-situ diffraction during isothermal annealing of CoSi films on Si (100). In-situ measurements allow capturing the initial stage of CoSi2 formation. An initial t3/2 time-dependent evolution is observed and attributed to 3D growth of individual nuclei. This first regime is followed after the coalescence of the nuclei by a classical parabolic t1/2 one-dimensional film growth. We evidence a marked influence of the initial Co thickness (50 nm vs 10 nm) on the growth kinetics. A significant slowdown of the CoSi2 formation kinetics is observed for the thinnest film, whereas the activation energy remains the same. These results shine a new light on the complex formation kinetics of CoSi2 during solid-state reaction between CoSi and single crystal silicon and bring new knowledge about what occurs in the ultra-thin film regime, which is important for nanotechnologies.