Effect of layout on electromigration characteristics in copper dual damascene interconnects

• EM behavior of Cu lines with width below 0.10 μm is strongly affected by the layout which surrounded the tested EM lines.
• The Cu EM lifetime declines as the number of local dummy lines increase, and the global dummy line density increases.
• Modifying the ECP process by reducing the deposition current effectively way to weakened this layout effect.
• The surrounding layouts must to be considered in assessing EM reliability of a real IC circuit in advanced technology.

This study demonstrates that the electromigration (EM) behavior of dual damascene Cu lines is strongly affected by the layout which surrounded the tested EM lines, especially for Cu line below 0.10 μm used for 40 nm or below technologies. The Cu EM lifetime declines as the number of local dummy lines increase, and the global dummy line density increases with the width of the Cu line below 0.063 μm. This work presents mechanisms of layout effects that explain the EM characteristics and can be exploited to improve the layout effect. Therefore, not only the stressed Cu line structures, but also the surrounding layouts must to be considered in assessing EM reliability of a real IC circuit in 40 nm or below technology.

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