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Ambient Copper-Copper Thermocompression Bonding using Self Assembled Monolayers

Published online by Cambridge University Press:  01 February 2011

Xiaofang Ang ,
Jun Wei ,
Zhong Chen  and
Chee Cheong Wong
Xiaofang Ang
Affiliation:
angx0004@ntu.edu.sg, NANYANG TECHNOLOGICAL UNIVERSITY, SCHOOL OF MATERIALS SCIENCE & ENGINEERING, SINGAPORE, Singapore
Jun Wei
Affiliation:
jwei@SIMTech.a-star.edu.sg, SINGAPORE INSTITUTE OF MANUFACTURING TECHNOLOGY, SINGAPORE, Singapore
Zhong Chen
Affiliation:
ASZChen@ntu.edu.sg, NANYANG TECHNOLOGICAL UNIVERSITY, SCHOOL OF MATERIALS SCIENCE & ENGINEERING, SINGAPORE, Singapore
Chee Cheong Wong
Affiliation:
wongcc@ntu.edu.sg, NANYANG TECHNOLOGICAL UNIVERSITY, SCHOOL OF MATERIALS SCIENCE & ENGINEERING, SINGAPORE, Singapore
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Abstract

A typical copper-copper thermocompression bonding process is carried out in an ultrahigh vacuum (UHV) or inert environment at a bonding temperature >300°C. The ultraclean environment serves a single purpose – to maintain oxide-free copper surfaces, allowing intimate physical contact between copper atoms. This study investigates the temperature dependence of direct copper bonding from room temperature to 300°C under ambient condition. An anomalous thermal dependence of bond strength occurs between 80°C to 140°C where an increase in bonding temperature within this regime is in fact, detrimental to joint strength. This is interpreted as a thermal competition between oxidation and bond formation. This study also demonstrates that by simply coating the copper surface with a self assembled monolayer of 1-undecanethiol prior to bonding, Cu joints can be successfully formed at close to ambient temperature without a vacuum, yielding joint shear strengths on the order of 70MPa. The densely packed monolayer serves to passivate the copper surface against oxidation under ambient conditions. The ultrathin organic monolayer structure, as compared to a bulk oxide layer, could be easily displaced during the mechanical deformation at the bonding interface which accompanies thermocompression. This method could be an effective simple bonding solution for three-dimensional integrated chips.

Keywords

bondingself-assemblyCu
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1112: Symposium E – Materials and Technologies for 3-D Integration , 2008 , 1112-E02-03
Copyright
Copyright © Materials Research Society 2009

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References

REFERENCES

1. Buchanan, K., “The evolution of interconnect technology for silicon integrated circuitry.,” in The International Conference on Compound Semiconductor Manufacturing Technology (GaAsMANTECH), 2002.Google Scholar
2. Liu, R., Pai, C.-S., and Martinez, E., “Solid-State Electronics, 43, 1003–1009, (1999).Google Scholar
3. Banerjee, K., Souri, S. J., Kapur, P., and Saraswat, K. C., “Proceedings of the IEEE, 89, 602–633, (2001).Google Scholar
4. Chen, K. N., Tan, C. S., Fan, A., and Reif, R., “Electrochem. Solid-State Lett., 7, G14, (2004).Google Scholar
5. Chen, K. N., Fan, A., , C. S. T. and, and Reif, R., “J. Electron Mat, 32, 1371–1374, (2003).Google Scholar
6. Brunschwiler, T. and Michel, B., “Thermal Management of Vertically Integrated Packages,” in Handbook of 3D Integration:Technology and Applications of 3D Integrated Circuits vol. 2, Garrou, P., Bower, C., and Ramm, P., Eds.: WILEY-VCH Verlag GmbH & Co., (2008).Google Scholar
7. Chen, K. N., Chang, S. M., Shen, L. C., and Reif, R., “J. Electron Mat, 35, 1082–1086, (2006).Google Scholar
8. Chen, K. N., Fan, A., Tan, C. S., and Reif, R., “J. Electron Mat, 35, 230, (2006).Google Scholar
9. Tan, C.S., Chen, K.N., Fan, A., and Reif, R., “J. Electron Mat, 34, 1598, (2005).Google Scholar
10. Chen, K. N., Tan, C. S., Fan, A., and Reif, R., “Electrochem. Solid-State Lett., 7, G14–G16, (2004).Google Scholar
11. Fan, A., Rahman, A., and Reif, R., “Electrochem. Solid-State Lett., 2, 534–536, (1999).Google Scholar
12. Chen, K. N., Fan, A., and Reif, R., “J. Electron Mat, 30, 331, (2001).Google Scholar
13. Chen, K. N., Fan, A., and Reif, R., “J. Mat. Sci, 37, 3441, (2002).Google Scholar
14. Whitesides, P. E. L. a. G. M., “J. Am. Chem. Soc., 114, 9022–9028, (1992).Google Scholar
15. Chen, K. N., “Copper Wafer Bonding In Three-Dimensional Integration,” in Electrical Engineering and Computer Science. vol. Doctor of Philosophy Boston, MA: Massachusetts Institute of Technology, 2005.Google Scholar
16. Chen, K. N., Tan, C. S., Fan, A., and Reif, R., “J. Electron Mat, 34, 1464–1467, (2005).Google Scholar
17. Youssef, T. H. and Essawi, R. A., “Czech. J. Phys, 29, 1266, (1979).Google Scholar
18. Cocke, D. L., Schennach, R., Hossain, M. A., Mencer, D. E., McWhinney, H., Parga, J. R., Kesmez, M., Gomes, J. A. G., and Mollah, M. Y. A., “Vacuum, 79, 71–83, (2005).Google Scholar
19. Derin, H. and Kantarli, K., “App. Phys. A, 75, 391, (2002).Google Scholar
20. Wieder, H. and Czanderna, A. W., “J. Appl. Phys, 37, 184–187, (1966).Google Scholar
21. Yamamoto, Y., Nishihara, H., and Aramaki, K., “J Electrochem Soc, 140, 436–443, (1993).Google Scholar
22. Jennings, G. K. and Laibinis, P. E., “Colloids Surf., A, 116, 105–114, (1996).Google Scholar
23. Feng, Y. Q., Teo, W. K., Siow, K. S., Gao, Z. Q., Tan, K. L., and Hsieh, A. K., “J Electrochem Soc, 144, 55–64, (1997).Google Scholar
24. Krishnamoorthy, A., Chanda, K., Murarka, S. P., Ramanath, G., and Ryan, J. G., “Appl. Phys. Lett, 78, 2467–2469, (2001).Google Scholar
25. Mikami, N., Hata, N., Kikkawa, T., and Machida, H., “Appl. Phys. Lett, 83, 5181–5183, (2003).Google Scholar
26. Tan, Y. S., Srinivasan, M. P., Pehkonen, S. O., and Simon, Y. M. C., “J. Vac. Sci. Technol., A, 22, 1917–1925, (2004).Google Scholar
27. Zucchi, F., Grassi, V., Frignani, A., and Trabanelli, G., “Corros. Sci., 46, 2853–2865, (2004).Google Scholar
28. Hutt, D. A. and Liu, C., “Appl. Surf. Sci., 252, 400–411, (2005).Google Scholar
29. Chen, K. N., Fan, A., and Reif, R., “J. Mat. Sci, 37, 3441–3446, (2002).Google Scholar
30. Ang, X. F., Li, F. Y., Wei, J., Tan, W. L., and Wong, C. C., “Thin Solid Films, 516, 5721–5724, (2008).Google Scholar
31. Ang, X. F., Chen, Z., Wong, C. C., and Wei, J., “Appl. Phys. Lett, 92, 131913, (2008).Google Scholar
32. Ang, X. F., Li, F. Y., Tan, W. L., Chen, Z., Wong, C. C., and Wei, J., “Low Temperature Direct Metal Bonding by Self Assembled Monolayers,” in Materials Research Society Symposium Proceedings. vol. 990 San Francisco, US, 2007, pp. 0990–B10-03.Google Scholar
33. Laibinis, P. E., Whitesides, G. M., Allara, D. L., Tao, Y. T., Parikh, A. N., and Nuzzo, R. G., “J. Am. Chem. Soc, 113, 7152–7167, (1991).Google Scholar
34. Leong, H. L., Gan, C. L., Thompson, C. V., Pey, K. L., and Li, H. Y., “J. Appl. Phys, 102, 103510, (2007).Google Scholar
35. Leong, H. L., Gan, C. L., Thompson, C. V., Pey, K. L., and Li, H. Y., “Effects of Nanometer-Scale Surface Roughness and Applied Load on the Bond Strength and Contact Resistance of Cu-Cu Bonded 3D ICs,” in Materials Research Society: Symposium Proceedings, Boston, MA, 2007, pp. 1036–M02-05.Google Scholar