Wafer-level electromigration reliability test for deep-submicron interconnect metallization

An automatic Wafer-level Electromigration Test (WET) System with interactive interface was developed. The WET System has the advantages of reduced stressing time and hence cost over the conventional package-level EM test. The automatic EM test with parallel stressing on multiple devices was successfully implemented. Interconnection lines linewidth of 0.32μm and 0.6μm and composite metal films AI-Cu (0.5%) with Ti/TiN top and bottom layer were processed and stressed. The activation energy E_a was found to be 0.76-0.86eV for 0.6pm metal lines over the temperature range from 235°C to 275°C. The values are compatible to those obtained using the package-level EM testing at 150 - 250 °C. For the 0.32pm metal lines, the activation energy El, was in the range of0.91-1.15eV.