Fabrication and characterization of copper interconnects of line-width down to 100 nm using a specially designed phase shift mask

• Mask simulation: alternating-phase-shifted scatter bars provides better performance.
• A novel mask is designed to fabricate 100 and 150 nm wide Cu interconnects.
• Integration process characterization: analytical tools are used extensively.
• Electrical characterization: very good results are obtained.

Resolution enhancement of traditional lithographic system is challenging. In order to improve resolution, simulation is performed and it is found that an alternating phase shift mask with alternating scatter bars provides better performance in comparison to conventional binary scatter bars. Using simulated parameters, a novel alternating phase shift mask with alternating phase shifted scatter bars is designed to fabricate damascene copper interconnects of line-width down to 100 nm. Extensive characterization of the integration steps is performed for process qualification. The electrical characterization of the fabricated copper lines is also performed to assure the interconnect quality. The result of this investigation is promising and leading to an integration scheme for mass production.

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