Materials Transactions, Vol.53 No.02 (2012) pp.453-456
© 2012 The Japan Institute of Metals

Reliability Enhancement of Thick Al–Cu Wire Bonds in IGBT Modules Using Al₂Cu Precipitates

Toshiki Kurosu¹, Khyoupin Khoo³, Yoshihide Nakamura², Keisuke Ozaki², Nobuhiro Ishikawa⁴ and Jin Onuki³

The reliability enhancement of Al wire bonds used in the insulated gate bipolar transistor (IGBT) modules is crucial to raise their reliability at the high operating temperatures of the motor vehicles in which the modules are widely used because cracking can occur in the Al. We investigated the bonding reliability of thick Al–0.5 mass% Cu wires, inside of which very fine Al₂Cu phases precipitated in both grain boundaries and the Al matrix. We found the reliability of the aged Al–Cu wire bonds was much better than the reliabilities for Al–Cu wire bonds without aging and conventional Al–Ni wire bonds for temperature change ΔT of 50 K. We also found from thermal cycle test results that Al₂Cu precipitates prevented crack propagation due to thermal expansion mismatch between Al wires and Si substrate.

(Received 2011/09/05; Accepted 2011/10/25; Published 2012/01/25)

Keywords: insulated gate bipolar transistor (IGBT) module, electric cars, reliability, thick aluminum wire bonds aluminum–0.5 mass% copper wire, AlCu precipitates

PDF (member)

PDF (organization)

Order Document

Table of Contents

REFERENCES

1. Onuki J., Koizumi M. and Suwa M.: IEEE Trans. Adv. Packag. 23 (2000) 108.
2. M. Mori, R. Saitou and T. Yatsuo: Proc. 5th ISPSD, (1993) p. 287.
3. Onuki J., Chonan Y., Komiyama T., Nihei M., Saitou R., Suwa M. and Morita T.: Jpn. J. Appl. Phys. 40 (2001) 3985.
4. Shimizu Y., Tomota Y., Onuki J., Khoo K. P. and Kurosu T.: Jpn. J. Appl. Phys. 48 (2009) 066511.
5. Kurosu T., Shimizu Y., Tomota Y. and Onuki J.: Mater. Trans. 52 (2011) 102–107.
6. Ciappa M.: Microelectron. Reliab. 42 (2002) 653.
7. W. Wu, M. Held, P. Jacob, P. Scacco and A. Birolini: Proc. 7th ISPSD, (1995) p. 330.
8. S. Sumi, K. Ohga and K. Shirai: Proc. Int. Symp. Testing Failure Anal., (1989) p. 309.
9. Onuki J., Koizumi M. and Echigoya J.: Mater. Trans. JIM 37 (1996) 1324.
10. Y. Koubuchi: Doctoral Thesis, Faculty of Engineering, Hokkaido University, (1997).
11. R. E. Smallman: Physical Metallurgy, (Butterworth, London, 1962) p. 299.
12. The Japan Institute of Metals: Materials Data Book, (Maruzen, Tokyo, 2004) p. 196 [in Japanese].
13. M. Hansen: Constitution of Binary Alloys, (McGraw-Hill, New York, 1958) p. 87.

© 2012 The Japan Institute of Metals
Comments to us : editjt@jim.or.jp