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Title: High precision thermal stress study on flip chips by synchrotron polychromatic x-ray microdiffraction

Abstract

The bending and residual stress of flip chips caused by the mismatch of thermal expansion between the chip and the substrate have been measured by polychromatic microfocused synchrotron x-ray beam. Precise orientation information as a function of position on the chip was obtained from Laue diffraction patterns, so that the bending angle with respect to a reference position at the center of the chip can be calculated at each position. This in turn allows deducing the local curvature of the entire flip chip. Local stress distribution was then mapped by applying a modified Stoney's stress-strain equation to the measured curvature. Our study shows that thermal stress on the circuits and the solder joints in a flip chip strongly depend on temperature and the distance from the center of the chip, indicating that interconnects at the corner and edge of a flip chip are of reliability concerns.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Advanced Light Source Division
OSTI Identifier:
984736
Report Number(s):
LBNL-3594E
Journal ID: ISSN 0021-8979; TRN: US1005964
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 107; Journal Issue: 6; Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36; ACCURACY; BENDING; DIFFRACTION; DISTRIBUTION; ORIENTATION; RELIABILITY; SUBSTRATES; SYNCHROTRONS; THERMAL EXPANSION

Citation Formats

Chen, Kai, Tamura, Nobumichi, Tang, Wei, Kunz, Martin, Chou, Yi-Chia, Tu, King-Ning, and Lai, Yi-Shao. High precision thermal stress study on flip chips by synchrotron polychromatic x-ray microdiffraction. United States: N. p., 2010. Web. doi:10.1063/1.3309750.
Chen, Kai, Tamura, Nobumichi, Tang, Wei, Kunz, Martin, Chou, Yi-Chia, Tu, King-Ning, & Lai, Yi-Shao. High precision thermal stress study on flip chips by synchrotron polychromatic x-ray microdiffraction. United States. https://doi.org/10.1063/1.3309750
Chen, Kai, Tamura, Nobumichi, Tang, Wei, Kunz, Martin, Chou, Yi-Chia, Tu, King-Ning, and Lai, Yi-Shao. 2010. "High precision thermal stress study on flip chips by synchrotron polychromatic x-ray microdiffraction". United States. https://doi.org/10.1063/1.3309750. https://www.osti.gov/servlets/purl/984736.
@article{osti_984736,
title = {High precision thermal stress study on flip chips by synchrotron polychromatic x-ray microdiffraction},
author = {Chen, Kai and Tamura, Nobumichi and Tang, Wei and Kunz, Martin and Chou, Yi-Chia and Tu, King-Ning and Lai, Yi-Shao},
abstractNote = {The bending and residual stress of flip chips caused by the mismatch of thermal expansion between the chip and the substrate have been measured by polychromatic microfocused synchrotron x-ray beam. Precise orientation information as a function of position on the chip was obtained from Laue diffraction patterns, so that the bending angle with respect to a reference position at the center of the chip can be calculated at each position. This in turn allows deducing the local curvature of the entire flip chip. Local stress distribution was then mapped by applying a modified Stoney's stress-strain equation to the measured curvature. Our study shows that thermal stress on the circuits and the solder joints in a flip chip strongly depend on temperature and the distance from the center of the chip, indicating that interconnects at the corner and edge of a flip chip are of reliability concerns.},
doi = {10.1063/1.3309750},
url = {https://www.osti.gov/biblio/984736}, journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 6,
volume = 107,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 2010},
month = {Fri Jan 01 00:00:00 EST 2010}
}