- Conference date: 14-16 June 2004
- Location: Austin, Texas (USA)
This paper presents scaling impacts on electromigration‐induced mass transport in narrow single damascene Cu interconnects. The Kawasaki‐Hu test structure was used to investigate such impacts. Line widths ranging from 0.12 μm to 0.20 μm were used to demonstrate the scaling impact that is due to the electromigration‐induced diffusion. Lifetime that is determined by resistance degradation decreases according to the decreasing line width at a fixed current density. This is caused by decrease of the effective incubation time and increase of the drift velocity. A product of drift velocity and a square line width has a linear dependence on current density. The activation energy is 1.2 eV for the effective incubation time, and is 1.1 eV for the drift velocity, respectively. They are independent of the line width. The activation energy suggests that the effective incubation time is the time to void growth from the Cu/SiCN interface to trench bottom through Cu grain boundaries. The grain boundaries provide nucleation sites for void growth in bamboo structures. Similarly, the interface diffusion at the Cu/metal liner on the sidewalls of the line contributes to void growth.
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