The effect of intermetallic bonding on blocking electromigration induced interfacial diffusion in Cu dual damascene interconnects

Minyu Yan*, Jong Ook Suh, King-Ning Tu, Anand Vishwanath Vairagar, Subodh Gautam Mhaisalkar, Ahila Krishnamoorthy

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In sub-micron dual damascene Cu interconnects, electromigration occurs mainly along Cu/SiN cap interface by void migration mechanism. In this study, immersion Sn surface treatment was employed after CMP and before SiN deposition. All the samples, with a line-width of 0.28 μm, were assessed by package level electromigration tests at 300°C under a current density of 3.6×106 A/cm2. We found that Sn surface treatment effectively introduces the Cu-Sn bonding to the Cu/dielectric interface and has influenced electromigration along the Cu/dielectric interfaces. Failure analysis shows that the samples with immersion Sn process have a median-time-to-failure almost 1 order of magnitude larger than the standard dual damascene samples. A careful characterization utilizing FIB and SEM cross-sectional images shows that the failure mechanism has changed due to immersion Sn surface treatment. After electromigration-induced void nucleation, its movement is blocked by the strong Cu-Sn bonding so that its growth is localized and occurs along grain boundaries. With the increased impedance to surface diffusion, failure analysis seems to indicate that grain boundary diffusion now participates in the void movement and growth, which is proposed to be the reason for the increased lifetime.

Original languageEnglish
Title of host publicationProceedings - 2005 10th International Symposium on Advanced Packaging Materials
Subtitle of host publicationProcesses, Properties and Interfaces
Pages153-155
Number of pages3
DOIs
StatePublished - 1 Dec 2005
Event2005 10th International Symposium on Advanced Packaging Materials: Processes, Properties and Interfaces - Irvine, CA, United States
Duration: 16 Mar 200518 Mar 2005

Publication series

NameProceedings of the International Symposium and Exhibition on Advanced Packaging Materials Processes, Properties and Interfaces
Volume2005

Conference

Conference2005 10th International Symposium on Advanced Packaging Materials: Processes, Properties and Interfaces
CountryUnited States
CityIrvine, CA
Period16/03/0518/03/05

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    Yan, M., Suh, J. O., Tu, K-N., Vairagar, A. V., Mhaisalkar, S. G., & Krishnamoorthy, A. (2005). The effect of intermetallic bonding on blocking electromigration induced interfacial diffusion in Cu dual damascene interconnects. In Proceedings - 2005 10th International Symposium on Advanced Packaging Materials: Processes, Properties and Interfaces (pp. 153-155). [1432067] (Proceedings of the International Symposium and Exhibition on Advanced Packaging Materials Processes, Properties and Interfaces; Vol. 2005). https://doi.org/10.1109/ISAPM.2005.1432067