Understanding Early Failure Behavior in 3D-Interconnects: Empirical Modeling of Broadband Signal Losses in TSV-Enabled Interconnects

• Published in: IEEE transactions on electron devices Vol. 69; no. 11; pp. 1 - 7
• Main Authors: Coakley, Kevin J., Kabos, Pavel, Moreau, Stephane, Obeng, Yaw S.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2022; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers
• Subjects: 3D-interconnects; Annealing; Broadband; chemical defects; dielectric polarization; empirical modeling; Engineering Sciences; Insertion loss; Integrated circuits; Interconnections; Optimization; Signal integrity; Silicon oxides; Silicon substrates; stochastic optimization; thermal cycling; Three dimensional models; TSV
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2022.3204936

We develop an empirical model for measured frequency-dependent insertion loss (<inline-formula> <tex-math notation="LaTeX">\vert \textit{S}_{\text{21}}\vert</tex-math> </inline-formula>). The model parameters are determined with a stochastic optimization implementation of the Levenberg-Marquard method. We compare measured <inline-formula> <tex-math notation="LaTeX">\vert \textit{S}_{\text{21}}\vert</tex-math> </inline-formula> on through silicon via (TSV)-interconnects, from two different providers, as a function of the extent of thermal annealing. The frequency-dependent changes in the electrical characteristics of the interconnect are attributed to silanol (Si-OH) and other dangling bond polarizations at the Si-SiO interface between the silicon substrate and the lateral silicon oxide that isolates the coaxial metal core from the silicon substrate. The changes in the polarizations are traceable to changes in the chemistry of the isolation dielectric during thermal annealing. The data also suggest that the evolution of the chemical defects inherent in the "as-manufactured" products may be responsible for some of the signal integrity degradation issues and other early reliability failures observed in TSV-enabled 3-D devices.