Aluminum-germanium-copper multilevel damascene process using low temperature reflow sputtering and chemical mechanical polishing

A low temperature multilevel aluminum-germanium-copper (Al-Ge-Cu) damascene technology was developed for the first time using reflow sputtering and chemical mechanical polishing (CMP). The maximum processing temperature for the fabrication of multilevel interconnections could be reduced to 420/spl deg/C using Al-1%Ge0.5%Cu from conventional reflow temperature of 500/spl deg/C. No degradation due to reflow heat cycles was observed in Al-Ge-Cu wiring resistance. Electromigration test results indicated that the mean-time-to failure (MTTF) of Al-1%Ge-0.5%Cu was longer than 10 years at the operating condition, which is similar to that of Al-1%Si-0.5%Cu. Al-1%Ge-0.5%Cu triple-level interconnection was successfully fabricated by use of reflow sputtering for filling vias and wiring trenches and successive CMP.<>