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Title: Thermoreflectance imaging of electromigration evolution in asymmetric aluminum constrictions

Abstract

Electromigration (EM) is a phenomenon whereby the flow of current in metal wires moves the underlying atoms, potentially inducing electronic interconnect failures. The continued decrease in commercial lithographically defined feature sizes means that EM presents an increasing risk to the reliability of modern electronics. To mitigate these risks, it is important to look for novel mechanisms to extend lifetime without forfeiting miniaturization. Typically, only the overall increase in the interconnect resistance and failure voltage are characterized. However, if the current flows non-uniformly, spatially resolving the resulting hot spots during electromigration aging experiments may provide better insights into the fundamental mechanisms of this process. In this study, we focus on aluminum interconnects containing asymmetric reservoir and void pairs with contact pads on each end. Such reservoirs are potential candidates for self-healing. Thermoreflectance imaging was used to detect hot spots in electrical interconnects at risk of failure as the voltage was gradually increased. It reveals differential heating with increasing voltage for each polarity. We find that while current flow going from a constriction to a reservoir causes a break at the void, the identical structure with the opposite polarity can sustain higher current (J = 21 × 106 A/cm2) and more localized joule heating and yet ismore » more stable. Ultimately, a break takes place at the contact pad where the current flows from narrow interconnect to larger pads. In summary, thermoreflectance imaging with submicron spatial resolution provides valuable information about localized electromigration evolution and the potential role of reservoirs to create more robust interconnects.« less

Authors:
ORCiD logo [1]; ORCiD logo [1];  [1]; ORCiD logo [1];  [1]; ORCiD logo [1];  [1]; ORCiD logo [1]
  1. Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907, USA
Publication Date:
Research Org.:
Stanford Univ., CA (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1540131
Alternate Identifier(s):
OSTI ID: 1417524
Grant/Contract Number:  
EE0004946; No. DEEE0004946
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 123; Journal Issue: 3; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
Physics

Citation Formats

Tian, Hao, Ahn, Woojin, Maize, Kerry, Si, Mengwei, Ye, Peide, Alam, Muhammad Ashraful, Shakouri, Ali, and Bermel, Peter. Thermoreflectance imaging of electromigration evolution in asymmetric aluminum constrictions. United States: N. p., 2018. Web. doi:10.1063/1.5005938.
Tian, Hao, Ahn, Woojin, Maize, Kerry, Si, Mengwei, Ye, Peide, Alam, Muhammad Ashraful, Shakouri, Ali, & Bermel, Peter. Thermoreflectance imaging of electromigration evolution in asymmetric aluminum constrictions. United States. doi:10.1063/1.5005938.
Tian, Hao, Ahn, Woojin, Maize, Kerry, Si, Mengwei, Ye, Peide, Alam, Muhammad Ashraful, Shakouri, Ali, and Bermel, Peter. Sun . "Thermoreflectance imaging of electromigration evolution in asymmetric aluminum constrictions". United States. doi:10.1063/1.5005938. https://www.osti.gov/servlets/purl/1540131.
@article{osti_1540131,
title = {Thermoreflectance imaging of electromigration evolution in asymmetric aluminum constrictions},
author = {Tian, Hao and Ahn, Woojin and Maize, Kerry and Si, Mengwei and Ye, Peide and Alam, Muhammad Ashraful and Shakouri, Ali and Bermel, Peter},
abstractNote = {Electromigration (EM) is a phenomenon whereby the flow of current in metal wires moves the underlying atoms, potentially inducing electronic interconnect failures. The continued decrease in commercial lithographically defined feature sizes means that EM presents an increasing risk to the reliability of modern electronics. To mitigate these risks, it is important to look for novel mechanisms to extend lifetime without forfeiting miniaturization. Typically, only the overall increase in the interconnect resistance and failure voltage are characterized. However, if the current flows non-uniformly, spatially resolving the resulting hot spots during electromigration aging experiments may provide better insights into the fundamental mechanisms of this process. In this study, we focus on aluminum interconnects containing asymmetric reservoir and void pairs with contact pads on each end. Such reservoirs are potential candidates for self-healing. Thermoreflectance imaging was used to detect hot spots in electrical interconnects at risk of failure as the voltage was gradually increased. It reveals differential heating with increasing voltage for each polarity. We find that while current flow going from a constriction to a reservoir causes a break at the void, the identical structure with the opposite polarity can sustain higher current (J = 21 × 106 A/cm2) and more localized joule heating and yet is more stable. Ultimately, a break takes place at the contact pad where the current flows from narrow interconnect to larger pads. In summary, thermoreflectance imaging with submicron spatial resolution provides valuable information about localized electromigration evolution and the potential role of reservoirs to create more robust interconnects.},
doi = {10.1063/1.5005938},
journal = {Journal of Applied Physics},
number = 3,
volume = 123,
place = {United States},
year = {2018},
month = {1}
}

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Works referenced in this record:

Electromigration—A brief survey and some recent results
journal, April 1969


Electromigration in thin aluminum films on titanium nitride
journal, April 1976

  • Blech, I. A.
  • Journal of Applied Physics, Vol. 47, Issue 4, p. 1203-1208
  • DOI: 10.1063/1.322842