DocumentCode :
608150
Title :
Low field TDDB of BEOL interconnects using >40 months of data
Author :
Croes, Kristof ; Roussel, Philippe ; Barbarin, Y. ; Wu, Chunlin ; Li, Yuhua ; Bommels, J. ; Tokei, Z.
Author_Institution :
Imec, Leuven, Belgium
fYear :
2013
fDate :
14-18 April 2013
Abstract :
Over 40 months of low field BEOL TDDB data obtained on different test vehicles with spacings ranging from 90-30nm and OSG low-k dielectrics with k-values ranging from 3.22.0 are summarized. For the dielectrics with k≥2.5, a simultaneous maximum likelihood fit with a fixed acceleration factor and varying distributional shapes is performed. By considering the log-likelihood of each model fit, this approach allows a comparison of fitted lifetime models. This approach also allows estimating the parameters of the impact damage model, which is more difficult to fit due to its multiple acceleration factors. From a statistical point of view and by using a 95% significance level, the results show that the power law and the impact damage model equally outperform all other proposed models and that their prediction to lower fields are very similar. As from a practical point of view the power law model is much more easy to use due to its limited number of fitting parameters, we propose to use the power law model for low-k dielectrics with k-value between 2.5 and 3.2. Regardless of the presence of a protection film, our low-field data obtained on the k=2.0 material show different acceleration factors at high and low fields. This suggests that different breakdown mechanisms are present at different fields and that, in order to allow reliable predictions to operating fields, future TDDB tests of highly porous films will require stresses at much wider field ranges.
Keywords :
electric breakdown; interconnections; low-k dielectric thin films; maximum likelihood estimation; BEOL interconnects; OSG low-k dielectrics; distributional shapes; fitted lifetime models; fixed acceleration factor; impact damage model; k-values; log-likelihood; low field TDDB; maximum likelihood estimation; operating fields; power law model; protection film; statistical point of view; time dependent dielectric breakdown; Acceleration; Data models; Dielectrics; Mathematical model; Maximum likelihood estimation; Reliability; Vehicles; Lifetime model; Porous low-k; Reliability; TDDB;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Reliability Physics Symposium (IRPS), 2013 IEEE International
Conference_Location :
Anaheim, CA
ISSN :
1541-7026
Print_ISBN :
978-1-4799-0112-8
Electronic_ISBN :
1541-7026
Type :
conf
DOI :
10.1109/IRPS.2013.6531969
Filename :
6531969
Link To Document :
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