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Title: Dislocation pile-ups as sites for formation of electromigration-induced transgranular slit-like voids in Al interconnects

Abstract

Electromigration-induced voiding in metal interconnects in Si integrated circuits is a serious reliability concern. The microstructure of narrow interconnects subject to post-pattern anneal is expected to be bamboo-like in character. These structures are best described as chains of single crystals, with grain boundaries perpendicular to the interconnect axis. In these microstructures, two distinct types of void morphologies have been reported in Al-alloy interconnects: large, wedge shaped erosion voids (E-voids), and narrow slit-like voids (S-voids). A summarized below, electromigration experiments conducted on single-crystal Al interconnects have clearly shown that the transition of erosion voids to slit-like voids is very strongly dependent on the crystallography of the interconnect, and also that there is some inhomogeneously distributed feature which triggers S-void formation, even in single-crystal interconnects. In summary, the authors feel that the strong crystallographic dependence of the S-voids, the possible effects of the enormous mechanical stresses (in excess of 1 GPa in some cases) which can exist in such interconnects, and the stochastic nature of the development of slit-like features, have not been adequately captured in the existing models. In what follows, the authors present a model for a role that dislocation pile-ups may play in reducing the energy of transition ofmore » E-voids to S-voids, and for controlling the location of this transition.« less

Authors:
;
Publication Date:
Research Org.:
Massachusetts Inst. of Tech., Cambridge, MA (US)
OSTI Identifier:
20023114
Resource Type:
Journal Article
Journal Name:
Scripta Materialia
Additional Journal Information:
Journal Volume: 42; Journal Issue: 1; Other Information: PBD: 17 Dec 1999; Journal ID: ISSN 1359-6462
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 42 ENGINEERING; MICROSTRUCTURE; ALUMINIUM BASE ALLOYS; INTEGRATED CIRCUITS; MONOCRYSTALS; THIN FILMS; DISLOCATIONS; ELECTROPHORESIS; VOIDS; MATHEMATICAL MODELS

Citation Formats

Srikar, V T, and Thompson, C V. Dislocation pile-ups as sites for formation of electromigration-induced transgranular slit-like voids in Al interconnects. United States: N. p., 1999. Web. doi:10.1016/S1359-6462(99)00320-6.
Srikar, V T, & Thompson, C V. Dislocation pile-ups as sites for formation of electromigration-induced transgranular slit-like voids in Al interconnects. United States. https://doi.org/10.1016/S1359-6462(99)00320-6
Srikar, V T, and Thompson, C V. 1999. "Dislocation pile-ups as sites for formation of electromigration-induced transgranular slit-like voids in Al interconnects". United States. https://doi.org/10.1016/S1359-6462(99)00320-6.
@article{osti_20023114,
title = {Dislocation pile-ups as sites for formation of electromigration-induced transgranular slit-like voids in Al interconnects},
author = {Srikar, V T and Thompson, C V},
abstractNote = {Electromigration-induced voiding in metal interconnects in Si integrated circuits is a serious reliability concern. The microstructure of narrow interconnects subject to post-pattern anneal is expected to be bamboo-like in character. These structures are best described as chains of single crystals, with grain boundaries perpendicular to the interconnect axis. In these microstructures, two distinct types of void morphologies have been reported in Al-alloy interconnects: large, wedge shaped erosion voids (E-voids), and narrow slit-like voids (S-voids). A summarized below, electromigration experiments conducted on single-crystal Al interconnects have clearly shown that the transition of erosion voids to slit-like voids is very strongly dependent on the crystallography of the interconnect, and also that there is some inhomogeneously distributed feature which triggers S-void formation, even in single-crystal interconnects. In summary, the authors feel that the strong crystallographic dependence of the S-voids, the possible effects of the enormous mechanical stresses (in excess of 1 GPa in some cases) which can exist in such interconnects, and the stochastic nature of the development of slit-like features, have not been adequately captured in the existing models. In what follows, the authors present a model for a role that dislocation pile-ups may play in reducing the energy of transition of E-voids to S-voids, and for controlling the location of this transition.},
doi = {10.1016/S1359-6462(99)00320-6},
url = {https://www.osti.gov/biblio/20023114}, journal = {Scripta Materialia},
issn = {1359-6462},
number = 1,
volume = 42,
place = {United States},
year = {Fri Dec 17 00:00:00 EST 1999},
month = {Fri Dec 17 00:00:00 EST 1999}
}