6:30 PM - 6:45 PM
▲ [16p-A403-20] Cu diffusion barrier property evaluation of 1-nm-thick PVD-Co(W) films by time-lag method
Keywords:Barrier property, time-lag method, 1-nm-thick Co(W)
With ongoing increasing demands of electronic products with higher performance, lower power consumption, and lower production cost, continual miniaturization of ultra-large-scale integration (ULSI) is required to achieve higher-density integration, while miniaturization requires a barrier/liner layer with lower resistance, better barrier properties, and higher adhesion to Cu than current Ta/TaN bilayer to address the electromigration (EM), stress-induced voiding (SIV), and resistance-capacitive (RC) signal delay. In addition, compared with the current bilayer- structure, a single barrier/liner that functions as both layers provide more volume for Cu, thereby decreasing the total resistance of Cu interconnects. Previously, Co(W) has been proposed to serve as a promising candidate material for a single barrier/liner layer with good performance as mentioned above. As one of the most important properties of barrier/liner, barrier properties were usually evaluated by qualitative method, without a common evaluation criterion, like the Cu diffusivity (D). Meanwhile, the D of Cu in an ultra-thin barrier layer is hardly evaluated due to the lack of a quantitative method with sufficient accuracy. Therefore, the time-lag method was modified to improve the accuracy of D evaluation, and it was successfully applied to evaluate the D of Cu in 4-nm-thick PVD-Co(W) film while it required a complicated structure. In this study, the time-lag method successfully conducted the quantitative evaluation of Cu barrier properties of 1-nm-thick PVD-Co(W) films in simple structures instead of the complicated structure (Cu/Targeted Co(W) /SiO2/Ti/Co(W)/SiO2/Si), which achieved the process simplification of the time-lag method.