Articles you may be interested in Grain structure analysis and effect on electromigration reliability in nanoscale Cu interconnects Appl. Simulation of the effects of grain structure and grain growth on electromigration and the reliability of interconnects Abstract. This paper combined experiments and simulation to investigate the grain size and cap layer effects on electromigration (EM) reliability of Cu interconnects. First the statistical distribution of EM lifetime and failure modes were examined for in laid Cu interconnects of large and small grain structures with two different cap layers of SiCN vs. CoWP. The CoWP cap was found to significantly improve the EM lifetime due to the suppression of the interfacial mass transport as a result of strengthening of the Cu/cap interface bonding. In addition, the grain size was observed to affect the EM reliability significantly, particularly for the CoWP capped structures. Resistance traces and failure analysis revealed two distinct failure modes: mode I with voids formed near the cathode via corner and mode II with voids formed in the trench several microns away from the cathode via. It was found that large grain size and strong cap interface reduced the mass transport rate and the void diffusion in the Cu line, leading to a longer EM lifetime and a higher proportion of mode II failures. A statistical simulation of EM lifetimes was also applied to Cu interconnects with grain structures generated by the Monte Carlo method. The simulation results for different grain sizes and cap interfaces are in good agreement with the experimental observations.

No abstract

The microstructure of Cu interconnects fabricated with Ta and Co liner materials had been examined by transmission electron microscopy and correlated to the electrical characteristics. Cu lines of 40 nm width were fabricated on 300 mm Si wafers by conventional CMOS backend processing. Electrical measurements performed immediately after fabrication of these Cu lines showed similar electrical resistance for Co and Ta liners. However, a 2.5-hour anneal at 375°C led to 5% more resistance reduction for Cu lines with the Ta liner than with the Co liner. Microstructure analyses showed that Cu lines with the Ta liner had 24% coherent Σ3 grain boundaries while lines with the Co liner yielded only 6% of coherent grain boundaries. In addition, Cu with Ta liner had a stronger 〈111〉 texture along the line width direction. However, the overall grain size distribution was similar between Ta and Co liners. These results suggest Co liner has some impact on Cu microstructures, which may be a root cause for the relatively higher line resistance.

No abstract

Green governance is the only way to build a community for humankind with a shared future. Existing research has concentrated more on the macro level rather than the micro level of green governance—the power hierarchy of the governance subjects and its influence on decision-making and the implementation of green governance. The board of directors is the main green governance body, and the consciousness and conducts of the green governance of board members are determined by corporate mission. As a result, we explored the mechanism of the impact of board power hierarchy on green governance performance through the influence of green governance conduct. To interpret this mechanism, we introduced relational contract theory and conducted an empirical analysis. The results show that board power hierarchy negatively affects green governance conduct. Corporate mission restrains the board power hierarchy’s negative influence on green governance conduct, showing that board power structure has a significantly positive effect on green governance performance through the mediator of green governance conduct. Therefore, the positive role of corporate mission is identified.