Effect of Cu at Al grain boundaries on electromigration behavior in Al thin films

Darrel R. Frear; Joseph R. Michael; C. Kim; A. D. Romig Jr.; J. W. Morris Jr.

doi:10.1117/12.51013

1 December 1991 Effect of Cu at Al grain boundaries on electromigration behavior in Al thin films

Darrel R. Frear, Joseph R. Michael, C. Kim, A. D. Romig Jr., J. W. Morris Jr.

Proceedings Volume 1596, Metallization: Performance and Reliability Issues for VLSI and ULSI; (1991) https://doi.org/10.1117/12.51013
Event: Microelectronic Processing Integration, 1991, San Jose, CA, United States

Abstract

The distribution of copper in aluminum thin films is examined with respect to how the copper can influence electromigration behavior. Al-Cu thin films annealed in the single phase region, to just below the solvustemperature, have 0-phase Al2Cu precipitates at the aluminum grain boundaries. The grain boundaries between precipitates are depleted in copper. Al-Cu thin films heat treated at lower temperatures, within thetwo phase region, also have 0-phase precipitates at the grain boundaries but the aluminum grain boundariescontinuously become enriched in copper, perhaps due to the formation of a thin coating of 0-phase at the grain boundary. Here, it is proposed that electromigration behavior of aluminum is improved by addingcopper because the 0-phase precipitates may hinder aluminum diffusion along the grain boundaries. It was also found that resistivity of Al-Cu thin films decrease during accelerated electromigration testing prior to failure. Pure Al films did not exhibit this behavior. The decrease in resistivity is attributed to theredistribution of copper from the aluminum grain matrix to the 0-phase precipitates growing at the grain boundaries thereby reducing the number of defects in the microstructure.

Citation Download Citation

Darrel R. Frear, Joseph R. Michael, C. Kim, A. D. Romig Jr., and J. W. Morris Jr. "Effect of Cu at Al grain boundaries on electromigration behavior in Al thin films", Proc. SPIE 1596, Metallization: Performance and Reliability Issues for VLSI and ULSI, (1 December 1991); https://doi.org/10.1117/12.51013

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available