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Civil-Comp Proceedings
ISSN 1759-3433
CCP: 99
Edited by: B.H.V. Topping
Paper 143

On the Modelling of the Direct Bonding of Two Silicon Surfaces

N. Cocheteau1, F. Lebon1, I. Rosu1, A. Maurel1, S. AitZaid2 and I. Savin DeLarclause2

1Laboratory of Mechanic and Acoustics, University of Aix-Marseille, France
2National Centre for Spatial Studies, Toulouse, France

Full Bibliographic Reference for this paper
N. Cocheteau, F. Lebon, I. Rosu, A. Maurel, S. AitZaid, I. Savin DeLarclause, "On the Modelling of the Direct Bonding of Two Silicon Surfaces", in B.H.V. Topping, (Editor), "Proceedings of the Eleventh International Conference on Computational Structures Technology", Civil-Comp Press, Stirlingshire, UK, Paper 143, 2012. doi:10.4203/ccp.99.143
Keywords: silicon direct bonding, modelling, finite element, surface energy, roughness, mechanical tests.

Direct bonding is a widely used process is microelectronics and increasingly on terrestrial and spatial optics. This bonding process is based on the contacting of two well-polished surfaces without the use of any adhesive or additional materials. Bonding is the result of interatomic bonds such as van der Waals or hydrogen bonds. This process requires a very precise physical preparations of surface (flatness and roughness controls), surface cleaning by solvents and finally thermal treatment (annealing) in order to increase the mechanical resistance of the bonded interface [1,2].

Despite many advantages such as high precision and dimensional stability of the assemblies, direct bonding is poorly reproducible. In addition, constraints involved in spatial application of the process (thermal fatigue, vibration, etc.) require the improvement of the mechanical performances of adhesive bonds.

Consequently, chemical and mechanical tests such as surface wettability, X-ray photoelectron spectroscopy or double shear tests were performed in order to characterize interfaces and observe the influence of the annealing. The results of analyses show the reversibility of the process, and an increase of the bonding energy with temperature.

The aim of this study, reported in this paper, was therefore to compare the various ways of modelling this particular type of adhesive contact in the framework of finite element methods. Classical models, such as the virtual crack closure technique [3,4,5] and cohesive elements models, and models in which adhesion is combined with cohesive elements are therefore compared [6,7,8,9].

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