Metrology and reliability of sub-45 nm Cu/ULK interconnects using multiline test structures

We used a multiline test device to evaluate the electrical linewidth, height, resistivity and reliability of sub-45 nm Cu/ULK interconnects. For 45 nm cu linewidth, an activation energy of 0.47 eV and current exponent n~2 are measured. A typical failure current of 36.6 MA/cm² at 170degC is obtained. Through electrical characterizations and finite element simulations, the interest of this polyvalent device for future VLSI interconnects is demonstrated.