Post electrochemical Cu deposition anneal impact on stress-voiding in individual vias

Stress-voiding is a critical reliability issue in Cu dual-damascene interconnects which could induce via openings. In our case, voids are typically observed at the edges at the bottom of vias. This location is correlated to a local delamination at Cu/Ta interface [E.T. Ogawa, J.W. McPherson, J.A. Ro...

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Bibliographic Details
Published in:Microelectronic engineering 2008-10, Vol.85 (10), p.2146-2149
Main Authors: Gregoire, M., Juhel, M., Vannier, P., Normandon, P.
Format: Article
Language:English
Subjects:
Annealing
Applied sciences
Cu interconnects
Design. Technologies. Operation analysis. Testing
Electronics
Exact sciences and technology
Impurities
Integrated circuits
Microelectronic fabrication (materials and surfaces technology)
Microstructure
Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
Stress-voiding
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Summary:Stress-voiding is a critical reliability issue in Cu dual-damascene interconnects which could induce via openings. In our case, voids are typically observed at the edges at the bottom of vias. This location is correlated to a local delamination at Cu/Ta interface [E.T. Ogawa, J.W. McPherson, J.A. Rosal, M.J. Dickerson, T.-C. Chiu, L.Y. Tsung, M.K. Jain, T.D. Bonifield, J.C. Ondrusek, W.R. McKee, IEEE Int. Rel. Phys. Symp. Proc. (2002) 312–321; Y.K. Lim et al., Stress-induced voiding in multi-level copper/low-k interconnects, IEEE Int. Rel. Phys. Symp. Proc. (2004) 240–245]. Then, Cu/Ta interface properties at the bottom of via seem to be in the critical path for stress-voiding. In this paper, stress-voiding on 300 mm wafers in individual vias for different post electrochemical Cu deposition (ECD) anneals is studied. Electrical results show the clear benefit of hot plate and short furnace annealings. Microstructural characterizations indicate that impurities accumulation at Cu/Ta interface during long annealings could drive preferred void nucleation.
ISSN:0167-9317
1873-5568
DOI:10.1016/j.mee.2008.04.029