Cart (Loading....) | Create Account
Close category search window
 

Electromigration in flip chip solder joints having a thick Cu column bump and a shallow solder interconnect

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $31
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

7 Author(s)
Nah, Jae-Woong ; Department of Materials Science and Engineering, UCLA, Los Angeles, California 90095-1595 ; Suh, J.O. ; Tu, K.N. ; Seung Wook Yoon
more authors

Your organization might have access to this article on the publisher's site. To check, click on this link:http://dx.doi.org/+10.1063/1.2402475 

In advanced electronic products, current crowding induced electromigration failure is one of the serious problems in fine pitch flip chip solder joints. To explore a strong resistance against current crowding induced electromigration failure, a very thick Cu column bump combined with a shallow solder interconnect at 100 μm pitch for flip chip applications has been studied in this paper. Results revealed that these interconnects do not fail after 720 h of current stressing at 100 °C with a current density of 1×104 A/cm2 based on the area of interface between Cu column bump and solder. The reduction of current crowding in the solder region by using thick Cu column bumps increased the reliability against electromigration induced failure. The current distribution in a flip chip joint of a Cu column bump combined with a shallow solder has been confirmed by simulation. However, Kirkendall void formation was found to be much serious and enhanced by electromigration at the Cu/Cu3Sn interface due to the large Cu/Sn ratio. Since this is a system of a limited amount of Sn and an infinite supply of Cu, the Cu6Sn5 transforms to the Cu3Sn after all the Sn content in the solder bump is consumed and the Cu3Sn can grow very thick; the vacancy flux that opposes the Cu flux will condense to form Kirkendall voids. The mechanism of electromigration induced Kirkendall void formation in the Cu column with the shallow solder joint is discussed. Furthermore, a v- ery large temperature gradient exists across the shallow solder interconnects, leading to thermomigration. Electromigration accompanied by thermomigration could replace current crowding as a serious reliability issue in using Cu column based interconnects.

Published in:

Journal of Applied Physics  (Volume:100 ,  Issue: 12 )

Date of Publication:

Dec 2006

Need Help?


IEEE Advancing Technology for Humanity About IEEE Xplore | Contact | Help | Terms of Use | Nondiscrimination Policy | Site Map | Privacy & Opting Out of Cookies

A not-for-profit organization, IEEE is the world's largest professional association for the advancement of technology.
© Copyright 2014 IEEE - All rights reserved. Use of this web site signifies your agreement to the terms and conditions.