Fatal Void Size Comparisons in Via-Below and Via-Above Cu Dual-Damascene Interconnects
The median-times-to-failure (t₅₀’s) for straight dual-damascene via-terminated copper interconnect structures, tested under the same conditions, depend on whether the vias connect down to underlaying leads (metal 2, M2, or via-below structures) or connect up to overlaying leads...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | en_US |
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2003
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| Online Access: | http://hdl.handle.net/1721.1/3826 |
| _version_ | 1811090313878437888 |
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| author | Choi, Z.-S. Gan, C.L. Wei, F. Thompson, Carl V. Lee, J.H. Marieb, T. Maiz, J. Pey, Kin Leong Choi, Wee Kiong |
| author_facet | Choi, Z.-S. Gan, C.L. Wei, F. Thompson, Carl V. Lee, J.H. Marieb, T. Maiz, J. Pey, Kin Leong Choi, Wee Kiong |
| author_sort | Choi, Z.-S. |
| collection | MIT |
| description | The median-times-to-failure (t₅₀’s) for straight dual-damascene via-terminated copper interconnect structures, tested under the same conditions, depend on whether the vias connect down to underlaying leads (metal 2, M2, or via-below structures) or connect up to overlaying leads (metal 1, M1, or via-above structures). Experimental results for a variety of line lengths, widths, and numbers of vias show higher t₅₀’s for M2 structures than for analogous M1 structures. It has been shown that despite this asymmetry in lifetimes, the electromigration drift velocity is the same for these two types of structures, suggesting that fatal void volumes are different in these two cases. A numerical simulation tool based on the Korhonen model has been developed and used to simulate the conditions for void growth and correlate fatal void sizes with lifetimes. These simulations suggest that the average fatal void size for M2 structures is more than twice the size of that of M1 structures. This result supports an earlier suggestion that preferential nucleation at the Cu/Si₃N₄ interface in both M1 and M2 structures leads to different fatal void sizes, because larger voids are required to span the line thickness in M2 structures while smaller voids at the base of vias can cause failures in M1 structures. However, it is also found that the fatal void sizes corresponding to the shortest-times-to-failure (STTF’s) are similar for M1 and M2, suggesting that the voids that lead to the shortest lifetimes occur at or in the vias in both cases, where a void need only span the via to cause failure. Correlation of lifetimes and critical void volumes provides a useful tool for distinguishing failure mechanisms. |
| first_indexed | 2024-09-23T14:41:22Z |
| format | Article |
| id | mit-1721.1/3826 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T14:41:22Z |
| publishDate | 2003 |
| record_format | dspace |
| spelling | mit-1721.1/38262019-04-11T08:18:41Z Fatal Void Size Comparisons in Via-Below and Via-Above Cu Dual-Damascene Interconnects Choi, Z.-S. Gan, C.L. Wei, F. Thompson, Carl V. Lee, J.H. Marieb, T. Maiz, J. Pey, Kin Leong Choi, Wee Kiong copper interconnect electromigration reliability The median-times-to-failure (t₅₀’s) for straight dual-damascene via-terminated copper interconnect structures, tested under the same conditions, depend on whether the vias connect down to underlaying leads (metal 2, M2, or via-below structures) or connect up to overlaying leads (metal 1, M1, or via-above structures). Experimental results for a variety of line lengths, widths, and numbers of vias show higher t₅₀’s for M2 structures than for analogous M1 structures. It has been shown that despite this asymmetry in lifetimes, the electromigration drift velocity is the same for these two types of structures, suggesting that fatal void volumes are different in these two cases. A numerical simulation tool based on the Korhonen model has been developed and used to simulate the conditions for void growth and correlate fatal void sizes with lifetimes. These simulations suggest that the average fatal void size for M2 structures is more than twice the size of that of M1 structures. This result supports an earlier suggestion that preferential nucleation at the Cu/Si₃N₄ interface in both M1 and M2 structures leads to different fatal void sizes, because larger voids are required to span the line thickness in M2 structures while smaller voids at the base of vias can cause failures in M1 structures. However, it is also found that the fatal void sizes corresponding to the shortest-times-to-failure (STTF’s) are similar for M1 and M2, suggesting that the voids that lead to the shortest lifetimes occur at or in the vias in both cases, where a void need only span the via to cause failure. Correlation of lifetimes and critical void volumes provides a useful tool for distinguishing failure mechanisms. Singapore-MIT Alliance (SMA) 2003-12-13T16:27:34Z 2003-12-13T16:27:34Z 2004-01 Article http://hdl.handle.net/1721.1/3826 en_US Advanced Materials for Micro- and Nano-Systems (AMMNS); 385354 bytes application/pdf application/pdf |
| spellingShingle | copper interconnect electromigration reliability Choi, Z.-S. Gan, C.L. Wei, F. Thompson, Carl V. Lee, J.H. Marieb, T. Maiz, J. Pey, Kin Leong Choi, Wee Kiong Fatal Void Size Comparisons in Via-Below and Via-Above Cu Dual-Damascene Interconnects |
| title | Fatal Void Size Comparisons in Via-Below and Via-Above Cu Dual-Damascene Interconnects |
| title_full | Fatal Void Size Comparisons in Via-Below and Via-Above Cu Dual-Damascene Interconnects |
| title_fullStr | Fatal Void Size Comparisons in Via-Below and Via-Above Cu Dual-Damascene Interconnects |
| title_full_unstemmed | Fatal Void Size Comparisons in Via-Below and Via-Above Cu Dual-Damascene Interconnects |
| title_short | Fatal Void Size Comparisons in Via-Below and Via-Above Cu Dual-Damascene Interconnects |
| title_sort | fatal void size comparisons in via below and via above cu dual damascene interconnects |
| topic | copper interconnect electromigration reliability |
| url | http://hdl.handle.net/1721.1/3826 |
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