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Nickel silicon thin film as barrier in under-bump-metallization by magnetronsputtering deposition for Pb-free chip packaging

Published online by Cambridge University Press:  03 March 2011

Y. Li*
Affiliation:
Applied Materials Inc., Santa Clara, California 95054
J. Chen
Affiliation:
Applied Materials Inc., Santa Clara, California 95054
C. Lazik
Affiliation:
Applied Materials Inc., Santa Clara, California 95054
P. Wang
Affiliation:
Applied Materials Inc., Santa Clara, California 95054
L. Yang
Affiliation:
Applied Materials Inc., Santa Clara, California 95054
J. Yu
Affiliation:
Applied Materials Inc., Santa Clara, California 95054
T. Sun
Affiliation:
Siliconware Precision Industries Co., Tantzu, Taichung, Taiwan, Republic of China
E. Ko
Affiliation:
Siliconware Precision Industries Co., Tantzu, Taichung, Taiwan, Republic of China
*
a)Address all correspondence to this author. e-mail: [email protected]
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Abstract

In the search for a Pb-free compatible under-bump-metallization (UBM) barrier material, magnetron sputtering of a nonmagnetic nickel silicon alloy (NiSi) target was used to deposit a low-stress polycrystalline NiSi thin film. In the reaction with SnAg3.0Cu0.5 solder, NiSi was found to have greatly reduced reaction and intermetallics (IMC) formation rates compared with sputtered NiV. A continuous layer of IMCs in NiSi UBM-solder joint remains stable after 10 reflows and 1000 h thermal aging tests, resulting in preferred bulk solder failure mode in ball shearing/pull testing. Our results demonstrate that NiSi is a highly promising thin film barrier material suitable for Pb-free solder bumping.

Type
Articles
Copyright
Copyright © Materials Research Society 2005

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References

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